GIC Guide to Tyco Trains No. 8: Power Torque Drive Locomotive Identification and Repair

The Official Goingincirclez Tyco "Power Torque" Drive Rebuild, Upgrade, and Identification Guide

by Tony Lucio

Is your Tyco locomotive barely able to get out of its own way? Does it squeal like a pig, stutter like a drunkard, or just sit there and buzz like a child sticking out her tongue? Does it run for a minute or two and then abruptly crash like an office worker coming off a caffeine high? Or are you already certain there's something wrong because you can see cracks, missing parts, and a small poodle sucked up into the motor?

You're not alone: Tyco's reputation was irreparably destroyed by the finicky locos they sold from the mid-70's onward. But have no fear, because they're easy to fix. So if you just dug the old set box out of the attic and are wondering how to resurrect the wreck within, you're in luck!


In the mid-1970's Tyco began using a new motor; originally exclusive to the Alco 430 and 630, it was gradually phased into the entire line (including steam locomotives) by the late 70's. Dubbed the "PowerTorque Drive" (or "PT" for short), it was supposedly developed over years to offer superior pulling ability and smoothness compared to the earlier, sealed "MU-2" motor/truck. These claims might have been true, but unfortunately the PT became more widely known for a more dubious honor: being temperamental, prone to faults, and easily killed. So it was something of a paradox: a motor which - given an example that ran well - would indeed outperform the earlier Tyco motors, and those from Bachmann and Life-Like as well. But then those others might run forever, whereas many a PT evaporated after just a few hours.

Despite these faults, the reality is that "millions" were made and it's likely that millions ran admirable service lives, even through today. Tyco even made continuous improvements during its entire production run - I have internal company documents which reflect testing being done even in the mid-80's. And if there's one thing that the PT definitely has over its MU-2 predecessor, it's that you can fix them with simple tools; the MU-2 motor trucks were riveted solid and could be quite tricky to work on, and difficult to find parts for today. A PT requires little more than a few basic tools and appropriate lubricants.

Convinced your PT hasn't quite bit the dust, but just needs a little TLC? Usually basic cleaning is all that's needed to make one run again. But if you've never done this before...


The following procedures can be used in any Tyco “PowerTorque” diesel locomotive manufactured from 1974 through the early 1990’s. With adaptation accounting for differences in assembly, these procedures may also be used on certain steam locomotives, including the tender-drive 2-8-0 and 0-8-0 “Chattanooga” (et al) Consolidations, and 0-6-0 Shifters. Note that beginning in the mid-1980’s, not all “Tyco” locomotives were actually manufactured by Tyco, and those substitute engines (usually made by Mehano, and thus similar to AHM and IHC locos) use completely different drive systems that cannot be serviced according to these instructions.

Locomotives featuring the PT Motor:

  • Alco C430: All post-1974*
  • Alco C630 ("Super 630"): All post-1973
  • EMD GP-20: All post-1975**
  • EMD F-7/9: All post-1975*, **
  • EMD E-7: ALL
  • EMD SD-24: ALL
  • "Sharknose" Baldwin RF-16: ALL (plastic)
  • GG1: ALL
  • "Diesel Switcher": All post-1976*
  • 2-8-0 Consolidation: ALL (tender drive)
  • 0-8-0 Steam: ALL (tender drive)*
  • 0-6-0 Steam switcher: All post-1980
  • *late train sets sometimes used Mehano-produced locomotives which do not have "Tyco" ID marks
  • ** The "New Mantua" (1978-2001) reproduced these models using an updated, serviceable version of the original MU-2 power truck

If you're new to model trains, please review this entire Repair Guide before performing any work. Steps are presented in a key order, and skipping steps might cause breakage of other parts that will require further work or the purchase of replacements. This Guide may seem long initially, but the whole procedure can be performed start-to-finish in an hour or much much less if you don’t create extra work for yourself. You might also want to review the companion Identification Guide: the text and photos there will familiarize you with the PowerTorque's unique parts and peculiarities and the many flavors it came in.

Also note: I have made every effort to illustrate, simplify, and provide caution as much as possible, but make no warranty to the usefulness or suitability of this PowerTorque Service and Rebuilding Guide - use it at your own risk.

Tools you will need:

  • Set of jeweler's / precision screwdrivers (the standard cheapo discount set of 7)
  • Needlenose pliers (hobby size will do)
  • Toothpicks
  • Small bin or container (film canister, pill box, baby food jar, etc)
  • Lint-free rag
  • Sandpaper or Emery cloth
  • Labelle #108 or "sewing machine" (plastic compatible) oil - DO NOT use 3-N-1 or "household" oil as it is too thick!
  • Grease (white or moly hobby grease)
  • Power pack with test leads
  • Soldering Iron *
  • Replacement traction tires - read below for more information

Tools you may be able to do without BUT I would recommend:

  • Kadee wheel cleaner / motor tester – versatile in place of wire test leads and easily cleans wheels
  • Xacto chisel blade – handy for scraping gunk
  • Xacto standard (#11) blade – handy for extending brush springs
  • Round needle file – for enlarging and truing gear bores
  • CA (Cynacrylate Adhesive / "Super Glue") – for securing pinion gears, headlight clip pins, and truck sideframes
  • Frosty beverage - because this should be fun and relaxing, duh!

*While a soldering iron may not always be required, keep in mind: the factory wiring and solder connections are very thin, fragile, and easily broken. Following this guide in order can prevent the need to solder, however it’s virtually inevitable that excessive or careless handling - not to mention dubious OEM assembly quality - will eventually require something to be resoldered! To avoid the need of a soldering iron, your goal should be to keep tension and weight off the wires as much as possible, and avoid bending them excessively. Even this may not be enough, so consider this a friendly, fair warning...

Got your supplies? Good! Let's get started, the backshop is open for business!


WIRING NOTES (not-quite-a-diagram)

Wiring of an early PT with separated headlight clip

Wiring of a later PT with integrated headlight

The pictures above should relieve any confusion regarding how a PT is wired up. Sometimes this is all that needs correcting in the case of a beginner's mistake.

The motor truck is always at the front of the locomotive, and always oriented as shown. Note how each truck's brass wheels are on opposite sides relative to each other. DC current is fed through one rail into the brass wheels and their metal axles, and on into the metal block... then across the wire into the second block and into its axles, then wheels, and finally the other rail and back to transformer - thus completing the circuit.

The rear truck is connected via wire to the motor as shown: note the two poles on the motor, identified by pair of brass terminal plates. The rear truck's wire connects to only one of these plates - conveniently, the one physically closest to the rear truck itself. The other terminal plate obtains its current feed directly from the block itself, which is why it's screwed in place for conductivity, while the rear-truck terminal plate is not. (It might be possible to electrically swap the connection points, but even though the loco might run, it would then run backwards compared to others.)

Note that a headlight is NOT necessary for the motor to run! It's merely spliced into the circuit. Look carefully at the first picture of the early PT drive with the separate headlight clip: if you remove the headlight and clip entirely, all you need to do is connect the rear truck to the motor terminal. On the newer PT, if you remove the direct-mount headlight clip, bulb, and bulb-feed wire, you're still left with a perfectly functioning motor circuit!

(Do you have one of the GG1 or C630's with the Reversing Headlights feature? Take note of the next two images:

Reversing headlight in a Super 630 - rear of loco shown

Reversing light module in the GG1, mounted above the "fuel tank" (not that a GG1 should have a fuel tank, but I digress)

The reversing lights are operated by a pair of diodes; one wired in series with each bulb. Pretty simple stuff, in the era long before DCC: incredibly, Tyco was the first to bring this only-recently-common feature to the mainstream, over 30 years ago!


If you’re reading this, you already suspect your PT motor is not performing up to snuff. So let's skip further troubleshooting for now and get right to disassembly, which will enable us to test it more effectively in a few moments.

First, review the following diagrams to familiarize yourself with the parts we'll be referring to:

While all Tyco diesels are easy to disassemble, some require a little finesse. The SD24, Alco Super 630, GP20, and C430 can all be stubborn when it comes to removing the fuel tanks and trucks; even F-unit and Sharknose parts can have a tight fit. It’s possible to crack loco shells or break truck sideframes if you manhandle them too much, so we're gonna give ourselves as much room as possible. Believe it or not, sometimes the removal of the motor is the hardest part - compared to that, the motor rebuild is straightforward and easy!

We need to remove the rear truck (the electrical “pickup truck”) first. So, remove both the front and rear truck sideframe caps to avoid breaking them during the rest of the process. Remove the screws from the bottom of each truck and set them aside. The truck caps should then simply lift off; some early versions have a tab at one end that snaps over the metal truck block and must be gently pried loose by inserting a jeweler's screwdriver into the slot provided. In either case, you can rock and twist the cap to slide the coupler through the locomotive pilot (if you're having difficulty, remove the coupler). Set the sideframe caps and screws aside - we won't need 'em again until reassembly at the end.

Both the motor and pickup trucks are installed into black cradles which snap into the body shell. Cradles vary from model to model, but generally follow two designs: 1) A two-piece “ring” cradle with integrated leaf suspension, and a tab on each side that snaps into the shell. 2) A one-piece “hat” cradle with metal coil spring suspension, and 3 or 4 mounting tabs. The following chart tells you which uses what so you can obtain parts if need be:

Locomotive Type

Front (Motor) Cradle

Rear (Pickup) Cradle

Cradle Removal

Tank Type

Tank Removal




Easy (Both)

6-tab or screws





Easy (Both)





Hat 3

Easy (F) Hard (R)

4-tab or screws




Hat 3

Easy (Both)

4-tab or screws



Hat 4

Hat 4

Hard (Both)

4-tab or screws



Hat 4

Hat 3

Hard (Both)






Easy (Both)






Easy (Both)




On models marked “easy” it's, um, easy to remove the cradle and truck block as one assembly. On those marked hard, the truck block often pops out of the cradle first, leaving the cradle inside the shell. Either way, grasp the rear truck and try to rock it out of the cradle and/or shell; you can use a firm grip when those stupidly fragile truck sideframes are out of the way!

Once the rear truck is free, unscrew the attached electric pickup feed wire, put the screw back in the truck for safekeeping and set the truck aside. If the cradle is still in the locomotive, remove it by gently prying the shell, twisting, or rocking it to get the tabs out.

With the rear truck out of the way, you now have room to dig in and spread the sides of the shell apart to remove the fuel tank without breaking anything. Some older GP20, C-430 and C-630 locos have fuel tanks held in place with two screws and are easily removed. On the F-unit and Shark it may be necessary to insert a thin screwdriver between the tank and shell and GENTLY pry; once one side is loose, repeat on the other side. Road-switcher units (later C430, C630, GP20 and especially the SD24) are often quite difficult because of the sturdiness of the shell: often you get one side free, only to have it snap right back when you free the other side! When this happens, rock the tank out by working from one end to the other. As a novice, you absolutely need to remove the tank from the road switchers in order to remove the motor and headlight without damaging the wires and solder connections. With the tank in place, there is no give in the shell to remove the motor cradles!

Now we can address the front / motor truck. Pop the front truck from the shell, in much the same manner you removed the rear truck. Make sure to get the cradle out of the shell as well. Once the truck is loose, BE VERY CAREFUL not to pull on the wires! Unless you have one of the revised motors with a direct-mount headlight, the headlight will be mounted to the shell and must be removed separately or else you'll break the wire. Gently pop the headlight bulb out of the clip, being careful not to bother its wire connection.

Generally, there's just enough slack in the clip wire to carefully set the truck down outside and next to the shell. Do this, and turn your attention to the headlight clip. It’s a push-clip that is press-fit onto a thin plastic pin (GG1 locomotives have two headlights in this fashion; older GP20's and C430's use a tiny screw). It’s easy to break the pin but you can remove the clip if you're careful: Grasp the clip with your needlenose pliers so that the pin is centered between the jaws. Then firmly but gently pull up on the clip; you can use a slight back-and-forth twisting motion but don’t overdo it. Just pull steady and straight, and the clip will slide off the pin. If the pin does break off inside the clip, don't feel bad; this is often unavoidable and you can simply glue it back in place later. (Note: The SD24’s headlight clip is a slide-fit into a light pipe and is easily removed).

Now with the motor truck loose and all wire tethers to the shell disconnected, you can set the shell aside. If the shell could use a good bath, now's the best time: use warm soapy water and an old toothbrush, and take care around decals and handrails. If the motor cradle is still attached to the motor, remove it. Be careful not to bother the wires too much; thread the cradle over the wires and set it aside.


BENCH TEST RUN: For this you'll need the power pack and some test leads. A brush-style wheel cleaner such as those sold by Kadee is especially useful.

First, remove any obvious debris: Hair, carpet fibers, chunks of old grease, white powdery zinc rot, metal shavings, etc - this stuff obviously shouldn't be there, and might be 90% of the problem in the first place! (Does your motor have the original grease? Keep in mind this is probably 25 years old or more - so rather than grease, it's probably more like mortar. This spells death to these motors! If the grease is brownish, or thick like peanut butter, you'll have to clean it out. But for now, assuming the motor has been running - no matter how poorly - leave the grease alone).

Connect one of the leads to the rear truck pickup wire or headlight clip. Touch other lead directly to the motor's metal block, and observe operation. The housing on the Tyco PT is conductive metal that completes the motor circuit; this is important to note and remember. If the motor performs better by touching the block and not the wheels, your problem is poor conductivity from the track caused by dirty wheels or contaminants in the axle bores. If the headlight is dim, the housing or solder connections are dirty. Try touching the lead to different spots – the top of the motor usually works well.

Adjust the speed on the transformer to test the full range: a good motor spins up quickly and responds smoothly. You may be able to see any gear binding or other issues more clearly. If the motor won't turn at all, you have to dig further. If the motor begins to feel hot or smell funny, STOP: you may have a worn or fried armature; see Servicing the Armature, or alternately Convert the loco to a Dummy. But if the motor is otherwise running OK and just seems sluggish, continue on.


Inspect the gears for defects: Look for worn or missing teeth; check the small pinion gear and make sure it is snug and does not spin on the shaft. Check the axle gears for cracks. If any parts are defective, you'll need to get replacements! It's usually easiest to get these from another engine, but never fear: when stripping another engine for motor parts, you can always convert the donor to a dummy. Don't forget to check the wheels! If a wheel is cracked, you may still be able to use it, but it ideally should be replaced and in the meantime traction tires will definitely be needed.

If your gears are OK, congratulations: all you need to do is clean them! Pull the small metal pinion gear off the motor shaft. Then, remove the large reduction gear and clean it, then remove the idler gears and clean them. Clean the gear axle spindles and the grease reservoirs around them - you can use the small screwdrivers, chisel blades, and toothpicks for this purpose as conditions dictate. USE CAUTION AS THE GEAR AXLE / SPINDLES CAN BE BROKEN AND IF THIS HAPPENS, YOU'RE S.O.L., "DONE SON", NEED A NEW MOTOR BLOCK and can only convert this one to a dummy.

The gears should now be shiny and free of oil, dirt, and grease... and so should the axle spindles they came from. But, BEFORE you lubricate and reassemble things, you should test-fit them first, dry. So reassemble the idler gear components; leave the large reduction gear out for now. Spin them with your hands and check the drag: they should spin freely. If an idler gear seems tight around its spindle, enlarge the hole *ever so slightly* with a needle file or a sharp #11 blade. You want the hole to be big enough to allow free-spinning movement, but not so large as to cause excessive play and "slop". You might also double-check the spindles for burrs or wear. Once the idler gears are fine, install the reduction gear and perform the same test.

(Why would the gears be binding on an axle after all this time? Answer: the motor block is cast out of zinc, and cheap zinc castings can absorb moisture and swell over time depending on environment. So over time the gear spindles could have swelled to a lager diameter - even if only .0001" - from when they were new, whereas the plastic gears do not change at all.)

Once your gears are spinning free and smooth by hand, they're good. But don't install and lubricate them yet - before you do that, why not give the motor armature one last test, with no load (gears) to slow it down?

If it's smooth, silly-fast, and responsive, you're ready to reassemble and enjoy your loco - skip to the Gear Reassembly section!

If it's slow, buzzy, or dead, you've got more work to do - continue to Armature Service below, or consider making a dummy.

Dummy Conversion: leave the gears OUT, and put the wheels back in. Without the gears the axles will spin freely. See the Motor Reassembly section if you need help putting the dummy truck together. You can also harvest the armature, brushes, and other components for use in other engines; if you leave the lighting alone, you can have a lighted dummy.


The armature is the wound wire spool which is literally the heart of a motor. The PowerTorque's armature is a unique and unusual design in the model train world with a number of inherent design faults, and it shares its basic traits with Aurora slot-car motors. The main problems with this armature are thin, weak windings that cannot handle much abuse in terms of overload - which means it doesn't take much to fry one in a train (versus a slot car). Other design flaws of the PowerTorque can cause excessive lubrication and debris to contact the windings and directly cause such failure. Also, the brush springs tend to be weak. That said, a good-running PT does prove the "conceptual suitability to task" of the PT design. "Durability", on the other hand, is often lacking. So don't be surprised if you need to work on it. How do you do that?

- Remove the two screws on the cover plate. Remove ONLY the screws, and set them aside - leave the cover plate alone and "attached" to the motor block for a moment...

- Now, carefully turn the motor over and lay it on its side, cover plate down - you might grasp the edges of the cover plate with your fingertips as you set it down. Now, lift up the metal block. The cover plate should remain on the bench, with the brushes and springs inside / on top of it. Claim these parts and do not lose them - they're impossibly small and will disappear! If the cover plate doesn't fall off loosely, you may carefully pry it loose but remember to watch for the springs and brushes.

- With the cover plate, brushes, and springs safely set aside, pick up the block (with armature still within) and inspect the armature cavity for debris and carbon buildup. Trace amounts are normal, but excessive crud needs to be removed. The commutator (shiny, brass part of the armature) should be, well, shiny... if it's not, gently clean the commutator with a pencil eraser or some rubbing alcohol on a Q-tip or lint-free rag. Finally, does the armature spin freely? If it doesn't, find out why: remove any debris, etc. caught between it and the magnets, or see the next step...

- There's still another test to determine if the armature is worth fooling with, and this requires its removal. To do this, grasp the small pinion gear firmly, then twist and pull gently to remove it. With the pinion gear removed, the armature can be separated from the motor. You should note however that the magnets keep it in place naturally...

- So, turn the motor block over with the armature on the bottom. If the armature falls out, then the magnets are too weak and the motor is essentially junk. If either of the magnets fall out, the same prognosis applies: the motor is unsalvageable and should be converted to a dummy. (Explanation: excessive heat can weaken the magnets, and also burns up the armature by then. Magnets that are too weak to hold the armature within their field are not up to task, and the motor is essentially worthless at this point. Similarly, if the magnets are removed the permanent magnetic field is destroyed, and remains much weaker when they are replaced. A traditional can-style motor can overcome this, but the PT design offers no tolerance margin for these types of problems).

- With the armature out, clean the housing thoroughly, removing any oils, dirt, and debris. DO NOT REMOVE THE MAGNETS UNDER ANY CIRCUMSTANCE!! Once clean, replace the armature into the motor housing; turn it by hand and ensure smooth, free movement.

When everything is cleaned and the armature spins smoothly, you're ready to put it all back together!


Note: if you did not need to service the armature, skip to the Gears and Wheels subsection below.

Armature Reassembly:

Get the cover plate, brushes, and springs. Lay the cover plate on the bench, place one spring in each brass hole in the cover plate, then rest one carbon brush on each spring. The brushes should have a "shiny" and a "dull" side: the shiny side touches the spring (the dull side touches the armature). Each brush should extend out of its hole by a small amount, say about 1 to 2 millimeters. If they do, proceed to Method A below. If they do not, gently extend the springs by gently twisting the tip of an Xacto blade inserted between the coils. DO NOT PULL ON THE SPRINGS.

IMPORTANT NOTE: If the springs are too long and prevent the brushes from resting within the holes, skip Method A and use Method B below.

--Method A: With the cover plate resting with its springs and brushes in place, place the armature subassembly housing back onto the cover plate by inserting the armature shaft into the bearing hole and pressing down. Flip over this full assembly and install the cover plate screws, tightening them just snug. Don't overtighten them as this can crush the brush springs and create too much drag on the armature. Apply a needlepoint drop of oil to the armature's axle bearing on the cover plate. Proceed to Gears and Wheels Assembly.

--Method B: You'll have to remove the brass spring plates from the armature cover, which can sometimes be difficult. Generally you need to pry the retention tabs aside and lift the plate up and over the pin so you can slide it out (remember which plate connects to the headlight bulb as you need to reinstall the plates in the same location). With the plates removed, install the cover onto the block. Insert the brushes - dull side down - then insert the springs. Now reinstall the brush plates - take care not to snag a spring and send it flying to neverland! Add a needlepoint drop of oil to the armature bearing.

Gears and Wheels Reassembly:

Place a small amount of grease on the gear spindles and reservoirs - not too much! Use just enough to help things turn smoothly; too much becomes a dragging goo that attracts lint and debris. Install the idler gears, then the reduction gear. Turn gears with fingers and ensure free movement.

With all the plastic gears in place, it's now time to install the pinion gear. Place a small drop of CA on the back ("teeth side") of the pinion gear, and carefully press it back onto the shaft. DO NOT PUSH IT ALL THE WAY DOWN TO THE BEARING! The CA is there to make sure the pinion won't spin loose on the shaft... if it gets in the bearing, you can imagine what would happen. You want the pinion to fully engage the teeth on the reduction gear; there should about a .5mm gap between the pinion and the shaft bearing.

Place a tiny, needlepoint drop of Labelle or sewing machine oil behind the pinion, on the bearing. FOR FUTURE REFERENCE: The Pinion bearing, and the armature bearing (on the cover plate), are the ONLY parts of a PowerTorque motor that should ever be "oiled"! Test the motor with leads... everything should be spinning nice and smooth. If it is, you're ready to reinstall the wheelsets.

Before installing the wheelsets, remove any surface rust or burrs from the metal wheels and axles, as those imperfections harm electrical pickup. Also, now's the time to replace traction tires. If you need new tires, you can get them from Walthers, eBay, or better model train shops; those made by Stewart / Calumet are recommended. I've also had success using "Goody" brand hair elastics from the cosmetics section of most retailers: the smallest size (usually available only in 3-size 100-count-ea. multi-packs) is a perfect fit; you might find a few duds in the batch but still net dozens of good ones for just a few dollars.

Install the wheelsets (remember that on 4-wheel trucks the plastic idler axle goes in the middle). Install the truck sideframe caps (if a sideframe is loose, secure it with a sparing amount of CA, contact cement, Walthers Goo or the like) and screw back into place.

Speaking of wheelsets, it's a good idea to check the rear truck's axles and wheels too. Remove any debris, burrs, etc. the same way as for the motor: the rear axles should spin very freely!

Test the motor again... It should be as good as before. If it's suddenly sluggish, loosen the truck cap screws and/or inspect your axles. You want the motor to turn at a fair rate of speed.


(If you are worried about breaking the truck caps, you can remove them once more (having tested your rebuilt motor with them in place) before completing the following steps... once the trucks are back in the shell, reinstall the truck caps).

If you have any suspect solder connections, NOW is the time to address them!

Add a small amount of grease to the cradle grooves on the motor block. Thread the gimball ring over the wires and snap it onto the motor - this part can be tricky as it's a tight fit by design; you might have to squeeze the ring from the corners to get it to slip on.

Taking careful note of your wire slack, reinstall the headlight clip into the shell. Grasp the clip with needlenose pliers, and with even pressure on both sides of the pin, press firmly. If your pin broke, use modeler's cement to reattach it. If your pin is lost, you can glue the clip with Walthers Goo or CA, but you'll need to apply pressure and be patient while it sets, and be extra-careful for the next few steps.

Insert the completed motor truck assembly into the shell and snap it into place (make sure not to snag or pinch any wires); make sure it swivels freely. The gears should be on the engineer's side of the loco (which is the right side of the cab if you were inside facing forward).

Thread the rear cradle over the pickup wire, then reattach the pickup wire to the rear truck, snap the cradle on, and install the rear truck into the shell. Remember to make sure all the brass wheels are on the left side of this truck (opposite of the motor truck). Install the fuel tank.


* * * * *

But wait, there's more...!?

A well-tuned PT is nice... but do you want something that performs a bit better? Got a block with busted spindles? You can try something like this - which is a loco I converted using a CD-tray motor:

* * * * *


Like all things Tyco, there were several versions of the PT drive made during its 15+ year production run. At worst these revisions prove that the PT was a flawed design; at best they prove that Tyco was at least trying to rectify some of the problems. Knowing which version you have can help date a certain piece, and prepare you for a few caveats when looking for spare parts. Determining which version you have is very easy and requires just a quick, visual inspection - but you'll have to remove the motor from the loco in some cases.

Let's get to the visuals!


The Powertorque debuted in 1974, in the Spirit of 76 Alco C430 and C630. Tyco claimed the new motor was the "result of years of development"... a specious boast given how quickly it was revised. Those first variants can also be found in some other early-70's C430 and C630 roadnames, and the first releases of the "new" plastic Sharknose Diesel.

The battle-worn "Super Spirit of '76" C630 above is equipped with a "Mark I" PowerTorque. These are easily spotted from underneath, as the truck caps are held in place with a single slot-head screw. The screw is actually unnecessary since there are beveled tabs at the ends of the truck sideframe cap, which securely snap in place on the housing. Also note that the couplers are in separate draft-gear boxes which only fit this PT truck (and the Rivarossi-drive Phase I 630).

Mechanically speaking, the pinion gear is brass; I own over 100 PT locomotives built from 1974 through at least 1988, and the only brass pinions are on the MarkI PTs. The reduction and idler gears are a thin, brittle plastic that wears easily.

The armature cover is a solid thick piece of plastic, with riveted posts. This provides good sealed protection, but retains heat.

The pickup truck is a unique housing that resembles an empty motor truck, but in fact is a unique piece. Because one side is hollowed out, the other side has more mass and as a result the truck could tend to lean on unlevel track.

These early PT motors typically run very hot and are generally poor performers.


Tyco quickly revised their "years of development" into this version, which makes a few improvements: The armature is the same, but the gears are thicker, tougher stuff. Notice the reinforcing ring on the reduction gear: this feature is not always present on later PT runs, but is common. The pinion (removed in this picture) is now cast from untreated zinc.

The big improvements are found on the backside, on the armature cover plate. Ventilation holes are now present, and instead of sealed riveted terminal posts, removable brush retainer plates are used. The plates make assembly and service a bit easier, while the vent holes address the heat issue, although not entirely.

The truck caps change to the common style, with 3 self-tapping screws and integrated coupler boxes. The taps for the screws are added to the casting.

Compared to the MkI, Mark II (and later) PT motor housings seem to be a weaker casting. It is possible to break the axle posts for the idler gears if the gears bind too hard. While this may yet be possible on the MarkI (they are scarce enough that I haven't yet happened to break one), it "feels" tougher.

Mark II PTs do perform better, but only just so. They are quite common in all diesels across the line.


The Mark III PT is noticeably revised, and appears around 1979 or so. A cast ridge is added around the reduction gear; the exact purpose is unknown but it may serve to keep fatal doses oil and grease from slinging into the newly enlarged (again) vent holes. In addition to making the original holes larger, a third one is added at the 3-o-clock position. Finally, the round post for the suspension spring is recessed into the top of the casting.

Tyco also simplifies the headlight mounting on some diesels by attaching it directly to the block. While this change does not seem to happen until the 80's, it is ridiculously simple in practice and - if you have ever had to fool with the headlight clips in the older units - arguably long overdue!

The armature cover once again sees big changes, with enlarged and reinforced ventilation holes. The brush clips are also revised. Finally, a note about "oil" is embossed, but the novice may not be sure of where exactly it is supposed to go, as the embossing is some distance from the bearing.

Finally, the axle bores are smaller. This requires the use of new, narrower axles on all wheelsets. Truck caps are also revised slightly to better secure these smaller axles.


The Mark IV PT does not entail any huge changes, but Tyco does attempt to idiot-proof it by now telling you where to put the oil. How nice!

Also, this particular example (from a GG1) has a felt pad under the pinion gear. Presumably this would absorb excess lubricant and protect the bearing. I have a reversing-light 630 with this pad as well.

PICKUPS (Versions 2, 3, and 4)

The Mk II (left) and Mk III & IV (right) use the revised pickup trucks shown above. These are better balanced than the Mk I version. Strangely, the hollow version weighs just as much as the filled-in one. Any performance difference is negligible, however note the smaller axle bores on the hollow version - you cannot use earlier (thicker) axles on these units. Motor blocks also saw similar changes to axle bores.

STEAM ENGINES (Chattanooga, Royal Blue, 0-6-0, etc) and Diesel Switcher

The PT drive was used in certain steam engines, most infamously in the tenders attached to the larger 2-8-0 Consolidation and near-identical 0-8-0 locos. The block is slightly modified for the special tender trucks, but the motor construction is again typical of those shown above. However, you cannot swap a diesel PT into a steam tender, because the steam tender PTs feature posts for attaching the outboard swiveling trucks, unique to the tender drives. Also, the PT axles have plastic wheels on both sides; power pickup is courtesy of the outboard swiveling tender axles (one rail) and the dummy Loco drivetrain (other rail).

The 0-6-0 Switchers use a PT in the loco itself (not the tender). You could swap a diesel PT into one of these, but be aware that the steam engines use different wheel inserts. Unlike the 2-8-0 and 0-8-0, electrical pickup is done solely via the loco (the tender is not needed). Similarly, the "Diesel Switcher" uses another modified PT block. Similar to the 0-6-0 version, electrical pickup comes from both sides of the block and not a separate truck. Aside from these traits, it is an otherwise mechanically standard PT design, and can be fixed with parts from any other loco.


There were many odd, inexplicable, inconsistent, and ongoing modifications to the PT over the years. Looking at the pictures above, you may note the reduction gear changes each time. The MkII shown without a pinion gear actually has a longer armature shaft that serves no purpose. The same white plastic used on that last reduction gear, was used for some MkIV armature covers. Then of course you have the headlight mounts, and pinion lubricant pads. None of these features directly affect the performance of the motor... but all of them may be seen in a dizzying array of combinations.

You can run any style motor truck, with any style pickup. You can swap the gears and armature from one to the other. The basic mechanics and gear ratio of the PT never did change, which makes this possible.

The biggest caveats with swapping parts are these:

1) Axle thicknesses changed (became smaller) on later production - presumably sometime in the late 70's to early 80's. You cannot swap thin and thick axle wheelsets, and some truck caps may tend to bind if overtightened.

2) The block castings are weak, and prone to absorbing moisture. Two blocks may appear identical to the naked eye, but one may have swelled just slightly out of tolerance - even as little as .001" would be enough to make gears and cradle rings and incredibly tight fit! But unlike the axle issues, fitment problems are easily overcome.


Please note, Comments are now closed. If you still need assistance troubleshooting your loco, I am happy to assist.... please contact me using the link in the "HOME" tab above...

All text, descriptions, and original photos © Tony Lucio. All Rights Reserved.

Offered for personal private use for informative and entertainment purposes ONLY. Redistribution in any form or media beyond, and Tony Cook’s HO Scale Trains Resource, is strictly prohibited without permission.

Comments, corrections, submissions and other communication are always welcomed! Feel free to comment or contribute by using the Contact Form. Thanks for reading!


Great pictures and more detail than mine - i mainly hit the basics in my video on power torque motors. Enjoyed your version

By Brian (not verified)

Eh, I wasn't trying to compete or anything, Brian :) But there's a lot of nuances to these that are worth noting - I tried to cover them all. But you're right, a basic view would be less intimidating to true newbies. So if you don't mind I'm going to post a link to your own vid. Thanks for the comment!

Brian's very good "Basic Turotrial" can be seen here:

Thanks again Brian! -GIC

By Tony L.


I bought a non-working Tyco 2-8-0 and I'm trying to get it going again. I can see where the right side tender wheels pick up the (-) side or the track, but I'm stumped on where the (+) side picks up power. I have it torn apart and there's two wires that come from the tender and attach to two copper strips underneath the boiler, but those appear to just be for headlamp power.

Any ideas?


By Conrad (not verified)

You're on the right track, but the boiler does more than operate the light. You're correct that both swinging tender trucks power one-half of the motor circuit, as both of them are connected by wires to the same motor brush plate.

The other half of the circuit comes from the boiler. Specifically, there should be two wires that connect the loco/boiler to the tender. One wire is from the headlight feed, and should connect to one of the tender trucks. The other wire (possibly red) connects to the other brush plate on the motor. This wire is fed via the loco drive wheels on the fireman's side; there should be a split copper plate inside the chassis - look carefully and you should see where this wire connects to a prong sticking up from the chassis, just under the cab. You should see some more wiring between the chassis and the boiler smokebox, this connects the same plates to the headlight and smoke (heating coil) element.

The 2/0-8-0 locos can actually be quite a pain to disassemble and repair, but it can be done. You WILL have to cut and splice the wires between the loco and tender though, otherwise you just won't have enough slack to work with.

Hope that helps! Thanks for the question. I modified the original post to clarify some of these quirks.


By Tony L.

I just want to say thanks for the info, I bought a Tyco 2-8-0 from eBay and during my testing the motor melted. I took the tender apart and found the armature had seized up. I had a another tyco pt diesel locomotive(runs very well)i was not using so i performed a little surgery based on your info and know my steamer runs very well. I am thinking of doing the CD motor conversion and would like some more info.... Thanks

By Rob (not verified)

You're very welcome, and thanks for letting me know it was helpful - that was the goal after all! The CD motor conversion has been quite popular; I hear there all all kinds of 'em running out there now. Have fun with your rebuild projects and thanks again!


By Tony L.


Excellent info. How about a basic wiriing diagram?

Cheers, Ian M

By Ian M (not verified)

...unfortunately it might take me a while, got a bit much on my plate right now.

In a meantime nutshell though, here's a few points to remember about the wiring. They'll hold true regardless of steam or diesel, and PT or MU-2 motor:

1) The brass wheels should be on the same side of any given truck.

2) When installed, each truck should have its wheels on opposite sides, compared to the other (i.e., motor truck on one rail, pickup truck on the other).

3) The lead from the pickup truck connects to one terminal / pole of the motor.

4) The other feed for the motor, comes from the motor truck (metal block) itself.

5) A headlight is not necessary for the motor to run. When installed, the headlight is simply spliced between the feeds.

This is all much clearer once you tinker around a bit. Sorry I don't have a clear diagram ready. I'll see what I can do but as I tell everyone, "don't hold your breath"...!

By Tony L.


Just wanted to say thank you very much for posting this information. My son and I recently unboxed my old train set with my favorite PT Chessie C630 (30+ years old). When power was applied to the track, it would light up and we could hear the motor spinning, but no movement.

Thanks to your site and instructions, it turns out the pinion bearing was spinning on the armature shaft (it had become loose). I'm going to glue it tomorrow and maybe we can get another few years out of it for my kids to enjoy as well!

Cheers and thanks again!

By Brian W. (not verified)

And thank YOU, because that's the some of the best compliments I could get, and exactly why I wrote this. I hope you get the loose pinion sorted out, and the Big Cat runs proud for your kids! -GIC

By Tony L.

I have a TYCO 2-8-0 steam engine similar to the Chattanoga RR from 1976. When I run the engine it begins a squeak that is intermittent, but on a fairly rapid basis and there is no point where the train begins to run normally for more than one revolution of my 4x7 oval. I have oiled the gears and the other moving parts and I have cleaned the track and wheels with alcohol. It seems that the squeak is generated from the engine area of the coal car, but I cannot be 100% sure.
When the squeak appears, the engine runs slowly and somewhat haltingly and the head lamp dims as well.
Any ideas?

By Frank T (not verified)

Hi Frank,

The PT motor is located inside the tender (coal car) of your locomotive. This squealing is a classic symptom of a motor that needs a little attention. Usually a drop of oil on the bearings will make the squealing go away, but while you have the motor out why stop there?

You should be able to remove the motor and its frame from the tender by spreading the tender shell apart to release the tabs that hold the frame in. Just be mindful of the wire slack that connects the tender to the locomotive, as there's just enough - but not too much - to work with.

When you have the motor out, make sure it's clean. When I've dealt with squealers it's usually due to excessive drag: at some point the armature wants to turn but the drivetrain is binding, and the pinion starts to slip on the shaft. Just get rid of the visible crud.

If a cleaning / debris removal does not solve the issue, then you may have to open up the motor and inspect the armature, and clean if necessary.

Don't run it too much when it's squealing though, as that will build up heat which will only compound the problem. The good news is that I've fixed a few of these, so your odds may be good.

Good luck!

By Tony L.

I just picked up a 2-8-0Chattanooga engine off ebay. I tried to run it and it would go slow and squeal badly. I put some 3n1 oil in the usual suspect spots and it didn't seem to help. As it was running all of a sudden the squeal went away and it picked up a lot of speed. Stopped it and it did it again. Every-time I stopped or changed speed it would start to squeal. Then in one of my closer inspections I noticed a wire was just off where it was supposed to be soldered. I soldered it back in place and all is well. Seems it was making intermittent contact and throwing the voltage off on the motor!

By scott (not verified)

I was working on an engine and had one of those cast pins break. What I did to repair it was to drill and tap a new centered hole 00-80 and used a brass 00-80 screw as a new post with a brass washer between the head of the screw and the plastic gear.
I put a miniscule amount of A-Line Flywheel cement on the tip of the screw where it threads into the big casting, being careful not to glue the gear to the metal casting or the new Axel/gear post made from the 00-80 screw. It seems to have done the trick.
I'm going to use the flywheel cement on the pinion gear to the motor armature after cleaning with isopropyl alcohol. I tried it once before, and it held awhile, but i think the armature shaft was oily when i applied the flywheel cement. It came loose.
Your guide online is a fantastic resource!

By Bill Mickey (not verified)

Wow... you know I never did consider something as simple as tapping for a screw? The one time I bothered to fix a broken pin (because it broke after I'd bored the think out for a CD-motor conversion), I drilled a hole where the stud used to be, then cut stock off the back of a drill bit and CA'd it in place. Wasn't holding my breath, but amazingly enough, it worked! Still didn't have enough long-term confidence to recommend that as a matter of course. I think I like your way better. Thanks!

By Tony L.

Dear Tony, Thank you for your compliments! I was wondering if you could recommend a source for the cd tray motor for the pt conversion. I've looked on ebay, and most of those motors are 4.5-5.9vdc motors with what looks like a cd player head on the end. If i get one of those, does the cd player head come off without destroying the motor? Looks like you machined the block out and left the pinion bearing as a reference/mounting area. Also looks like you used silicone caulk/adhesive to mount the new motor as well as insulate it. Also, how is it wired?

By Bill Mickey (not verified)

I'm afraid I can't recommend a specific consistent source, as I'm currently blessed (cursed) to have innumerable dead computers at my disposal via work. One day I simply removed a half-dozen CD-rom drives, cannibalized the motors, and then experimented to see which one(s) would fit the best. The lower the profile, the better. To clarify though, I've used the motors that operate the disc tray - not the ones that spin the disc.

I had to reuse the pinion since none of the gears are changed, so yes, this is a reference. You may have to bore the bearing and pinion out slightly if the replacement motor has a thicker shaft. The silicon adhesive just simply did the job. Actually I think it may have been hot glue ;)

Wiring is easy: still a two-wire system. One connects to the rear truck, and the other wire connects to the block you've just bored out. I wasn't concerned about the headlight on mine, but you could splice one in much like the originals.

By Tony L.

Hey, Tony,

Thanks for this great page! My uncle gave me a SD-24 Burlington. The motor ran, but the reduction gear spindle had broken, and the gear was gone. I know you said I was "done,son," but I'll drill out the spindle and replace it with another one I have. As for the gear, I have several extras that will fit. Thanks again.

By Abel R. (not verified)

Glad you found it helpful. As for the broken pin issue, you're on the right track. See Bill's idea, which coaxed my own fix, below. Nice to see these things coming alive again. The Burlington SD24 is a good looking engine.

By Tony L.

wow great site! late as always and working on old ho train that hasn't sean the light of day for 8 years for x-mas, had 2 old engines bought at yard sales worked on both and got 1 good one with your help, thanks, have you every use this trick on armature service? I use blue painters tape to hold the brushes and springs in place then installed the armature pulled out the tape then put it in the houseing worked great thanks again for the wonderful site & MERRY CHRISTMAS!!!!!!

By michael lucchesi (not verified)

Glad you found my site just in time for Christmas, ha ha... I hope that old train is once again putting some smiles on faces this year.

That tape idea is a good one. My only caveat would be to make sure the adhesive isn't so sticky as to gum up the works, or the tape so fragile as to rip and leave remnants inside the armature. As you suggest, blue painter's tape probably has just the right amount of durability and "stickiness" for the job. Great idea - thanks for sharing!


By Tony L.

I had a problem with my motor too The pinion gear sliped off! What my friend did was rough up the shaft so that it wouldn't slip He used abit of STP on motor Rearanged the wheels & now it runs great Still using the the Power Torque motor hehe

By microbuss (not verified)

One other thing I forgot to mention is that on my motor the wires were only GLUED on not soldered! So watch out when you take apart these Power Torque motors Wires may just fall completely off! lol

By microbuss (not verified)

I've never seen one that came from the factory that way. But not everyone knows how to solder, especially children who often used/abused these in their youth. I can remember many kludge fixes I attempted with glue and tape as a child, before I was deemed "old enough" to be trusted with a soldering iron. I'm willing to bet something similar happened to yours in its previous life. The factory always soldered them, although I've seen connections that were poor enough to cause the blob to completely pull right off the terminal plate.

By Tony L.

Thanks for doing this article! I followed it and got my Engine back running again! One question/Thought though: At least my version of the Chattanooga has an all copper block for the motor.. I cleaned up the corrosion around the gears but I'm guessing the issues I had were related to this in the first place. Is there something I could coat the whole block with to prevent further corrosion? I was thinking carefully applying and polishing using car wax might do the trick.. oil/grease would probably attract too much debris..

Appreciate your thoughts!

By Mike (not verified)

Glad your engine is running again!

I know the "copper" blocks you're referring to, for some reason it seems a lot of the tender-drive PTs look like this. But I'm pretty sure they're not actually copper, and the color instead results from some sort of plating or chemical treatment used to blacken the the frame that is visible below the tender body shell.

Interesting thought about coating the block to prevent oxidation. I suppose this could work but there are a few caveats: You'd need to keep the coating off mechanically interacting portions (gear spindles, etc), as well as locations that need to be electrically conductive (axle bores, terminal plate mounts, armature cavity, etc). Assuming you could do this, you then have the issue of durability and wear: would heat wear the coating off (if carwax can withstand Arizona sunblaze it might indeed do OK), and if it does wear off what would happen when it mixes with the grease and/or gets into the gears?

It's an interesting consideration. For myself I'm not inclined to see too much benefit given the plentitude of replacement parts on the used market. But it might be fun to experiment with. If you give it a try let us know!

By Tony L.

Excelente ,yo también he remotorizado algunos modelos TYCO,por falta repuestos,también use un piñon de bronce de un reloj de cuerda,he hecho varios experimentos,gracias por tu información.Tengo una gran colección de máquinas ,más de 28 marcas,americanas y europeas.-

By Germán Osvaldo (not verified)

Please Post This For PT Steam Tender-Drive Lovers:

The PT motor in the Tender Drive 0-8-0 and 2-8-0 pose very unique repair problems. In addition to all the noted PT flaws found in the diesel units, the tender unit has one that I have not seen addressed anywhere. The drive axles have plastic wheels on both ends, grooved for traction rings. The Non-Geared traction wheel will often be split and coming off the axle. (on rare occasions I have found the thicker geared wheel the same, causing extreme gear-binding and damage issues) This is usually from spending cold winters and hot summers in someone's garage or worse, the attic. Subsequently I have purchased a large number of unopened, unused, "MINT" Tender-Drive units already suffering this condition, rendering them inoperable.
Over the years (30 or so) I have employed several repair solutions, some not so successful as others.
1) Glue cracked wheel back together with super-glue: usually cracks right away attempting to re-mount on axle.
2) Super-glue cracked wheel, fill outer wheel basin with steel-epoxy to strengthen, drill wheel hole to axle diameter; worked better.
3) All of the above, plus epoxy steel washer to backside of wheel to inhibit crack expansion; Better, but causes clearance issues depending on washer thickness and availability.
4) Steam PTs are Electrically Backwards so, Diesel axles will NOT work, even thought they fit. (the non-geared flange is brass and on the wrong electrical side of the Tender drive!)
5) Best Solution: Collect as many good PT Tender drives as humanly possible and use Unbroken Drive axles!

Most of the 1977 and older PT 2-8-0s have superior tender drive axles and parts in general, even factory Tyco Clear Vinyl Traction Tires that never rot! (some 1st edition Tyco Brown-Box diesels have these also!)
However, the oldest have the highest instance of brittle cast-frame crumbling due to age and damp storage environment.

The 1980-82 PT Tender Drives almost always have Plastic motor frames, and the highest rate of Drive-Flange Wheel Splitting.
Even worse, all the 0-8-0 models have no valve gear, which looks cheap, and renders them (in real life) inoperative. (picky, picky)

Most of the Best Tyco PT Steamer paint jobs and road names came after 1980. Only 2 were fully-outfitted as a 2-8-0; the Royal Blue and the always desirable red/silver GM&O.

Be aware: the 2-8-0 Royal Blue was made in both versions: The Better 1975-77 and the Cheaper 1978-1982 Version.

Conversion of the 0-8-0 to include operating valve gear, and even a pilot bogie, is possible, but tricky, as it requires blending of older production models with later ones. I usually save this kind of surgery for the nicer road names like the Dark-Green Southern
0-8-0 with gold tender trim, the very scarce Great Northern 0-8-0, and the Canadian Pacific 0-8-0. Sometimes I just can't stand seeing any "valve gear-less" steamers, so I will add that to all the other 0-8-0 like the Clementine, #27 Light Green Southern, Flat Black Chattanooga, and even the Brown-Roof Chattanooga #1261.

I am delighted to hear about the CD-Tray Motor conversion suggested here, and plan to try that as soon as I can. In fact, such a modification may at last allow DCC addition to these Locomotives, previously not possible due to the inability to isolate the Tender-Drive electrical wiring

By Graves Clayton (not verified)

You're right about the wheel issues, I touched on them briefly in the steam section originally, but not nearly in as much detail. I don't actually have very many of the steam engines myself, but hope to rectify that eventually, ha! I'd noticed the cheapened (missing) running gear and plastic chassis on later models, but was unsure when exactly this took place. I didn't realize the Royal Blue and certain other roadnames kept the valve gear throughout... a nice touch if a bit too little, too late.

I can tell you that, oddly enough, the diesels are not immune to the cracked plastic wheel issue. I've seen many that have cracked wheels, especially the geared, center idler axle on 4-wheel trucks. This problem dates back to the earlier MU-2 drives as well... just try to find one of those without cracked plastic traction wheels, and you might be looking for a long time. Fortunately in my experience it's usually just the traction wheels that have this issue, and tires do tend to eliminate any ill effects (finding tires that fit the narrower groove on those older motors is another challenge entirely).

Thanks for your tips on repairing the wheels. Agreed that swapping parts is usually the best choice, but at least an industrious person short of access to donor units has some options....

I have a GM&O 2-8-0 en route as of this writing. Still looking for that pretty GN myself...

Thanks for writing!

By Tony L.

Hi again, Tony.

There is an industrial o-ring available for the old Mantua narrow groove wheel, My father found them in Richmond, VA before he passed away. I have all of his HO Trans and parts, but most are packed up. When I find out what he bought, I will let you know.

I think I may have found a way to substitute the diesel drive wheels into the steam PT Chassis, but It may result in a reverse direction locomotive. Also, reducing the number of traction tires to only 2 may render it useless to pull any cars. The tender drives have no room for traction weights, (like diesels have) and really need all 4 traction tires. Still, the isolated CD Tray motor and some stick-on automotive wheel weights may open new possibilities. I have also entertained installing mu-2 powered and un-powered trucks in the tender as well, but that may take the tender too far away from prototype appearances. (like the Tyco is all that accurate to begin with?) Well, there are still more avenues to explore at least.

And yes, I have a few cracked diesel drive wheels, too. Fortunately there are more diesels for cannibalizing, at lower prices!

I have only managed to snag one 1st edition 630 w/Rivarossi chassis, but it was abused and missing 1 lower drive shaft. I am still trying to match up a compatible shaft, but so far no luck.

At one time I had restored at least one of every example of the PT Tender Drive Steamers 0-8-0, and 2-8-0. Sold half of them in 2007 just for financial needs. Also had all of the E-7, SD-24, 430, GG1, and 630 models (except 3 of the 4 Rivarossi 630) and sold 70% them in 2007 as well.

The PT is short on durability, but Tyco had such a diversity that I find them irresistible. Ok, they are cheap and intriguing and keep me out of meanness during the long bleak winter months, lol!

By the way, did you just win the Tyco GM&O on E-Bay for $52.00? If so, congrats! You did so by besting my $51.00 maximum bid, lol!

I am part-way through performing an 0-8-0 to 2-8-0 upgrade on a Great Northern PT Steamer (only the 2nd I have ever found in 30 years) using original Tyco parts, of course. Will probably make it available to sell if I get lucky enough to find another GN in need of help.
I have done extensive PT repairs, and, like you, find the riveted contact motors to be despicable. (and likewise the "shark" locos they are most commonly found in) I have done reverse lighting upgrades to nearly every 630 I touched, and the older 430s that have rear lenses.
Glad to have found your page, as I thought myself to be the only die-hard PT mechanic.

There is a Tony Cook, who has the only other dedicated Tyco site I know of. But he appears to collect and document more than actually doing restorations. Still, he has been a wealth of information in my own collection and restoration endeavors.

By Graves Clayton (not verified)

The pinion gear on my silver streak engine keep slipping on the shaft. If I push it back in the train will work for a few minutes then it will slip again. How can I keep it from slipping out of place?

By roy (not verified)

Hi Roy,

This is a common problem. There are things you can do to prevent this:

1) Make sure there is no crud in the other gears. The shaft will spin loose inside the pinion is there is too much resistance to turn the pinion otherwise. So remove any extra resistance and the problem may subside.

2) That said, loose pinions can still persist... so you might have to use some adhesive. In my Guide I advice a carefull application of Cyanoacrylate Adhesive ("Super Glue"), but I've heard of other folks having success with various expoxies, nail polish, and even soldering. The key is no NOT get any adhesive into the bearing, or else you'll create a entirely new / different problem...!

By Tony L.

Hi Tony.
Could you please post this Service Update for Power-Torque Tender Drives;

Primary Goal: Reduce (or eliminate if possible) the annoying wobbling and shaking of the tender-drive units.
Primary causes found:
1) Cracked plastic drive axle wheels, and poor wheel spacing
2) Bad traction tires on drive wheels
3) Poor electrical pickup from tender unit in curves, switches, crossings, etc.
4) Lack of traction weight

New and Improved Solutions:

Causes 1 and 2 both combine to make the drive wheels out-of-round on the axle. First you have to identify which wheels are out of round. This is exceedingly difficult because the tender-drive axles have 2 traction wheels per axle, not 1 like the diesels. With 4 bum drive wheels, the tender-drive tends to wobble not just left-right or front-back, but in all 4 directions, giving the appearance (and performance) of of an out of balance gyroscope! The following should be done after disassembling drive from the tender shell
and drive frame completely. (Now would be a good time to perform any desired motor maintenance as well)

Step 1) Replace drive axle sets with the ones from the P-Torque diesel. Admittedly they have brass wheels and will not match all
of the other steel wheels on all of the PT Steamers, but you can paint them all black on the sides to match later. If you
prefer all the metal wheels to match for appearances (which I do) follow the following steps to make your own drive sets.
For this, you will need a pair of non-drive wheel sets from spare/parted tender-drive units.
A) Remove the Non-geared-flange drive wheel from the axle. These are cracked or split in about 80% of the units.
Keep the traction tire and discard the wheel. Grasp the bare axle end with pliers and twist off the geared flange by hand so
as not to damage the flange or gear teeth. Remove the plastic wheel from a non-drive wheel set, leaving the steel wheel in
place. Now press, by hand, the geared-flange wheel onto this axle, and properly space the 2 flanges using a piece of HO
scale track. This will get your tender-drive almost as smooth as most of the diesels!

Step 2) Traction Tire Replacement:
This is very important to give the wheel a good round shape that does not bounce up and down. It is also the hardest to
correct due to the quality of available traction tires. The Stewart #515 are commonly available, but often tend to be of
uneven thickness once stretched onto the wheel flange. While improving traction, this still allows some wheel bouncing.
I have obtained the best results with original vinyl traction rings salvaged from older (1975-77) Tyco diesel and tender-drive
PT units.

If you get this far, you have already eliminated about 90% of the shake & wobble, as well as those pesky poor electrical pickup issues (especially at switches and crossings). This much has hopefully now fixed causes #1, #2, and #3. The last fix is easiest.
Remember, the PT diesels have a nice big weight set in the center to absorb vibrations and add wheel adhesion. Whereas the PT tender-drive has no weights at all, and has to push an non-powered 8-driver locomotive to boot!

Step 3) Traction Weight:
After eliminating 2 o the 4 traction wheels of the tender drive, your steamer (depending on train length or car type) may not
have enough pulling traction. After the above drive-axle refit, reassemble motor and frame using the metal tender frame
from older Tyco 2-8-0 models. (Note: the Royal Blue continued to be equipped with the metal tender frame all the way up
into the mid 1980's, even when all other units came with plastic frames!) The metal frame is 4 times heavier and may be
enough weight by itself to solve this. If not, or you only have the plastic frame available, strategic weight addition is the
ultimate solution. Flat lead automotive self-adhesive tire balance weights are affordable, compact, and simple to add to
the tender shell or frame. Be very careful not to over-weight the unit which will overwork and burn out the electric motor.

I have experimented with adding a 3rd drive axle to the center of the motor block. It adds back another Traction wheel and electrical pickup wheel, but adds a bit more work to the whole operation. Not only does it require using the lighter plastic frame in order to expand the wheel openings, but then you have an extra drive wheel and tire to balance and adjust to work out the wobble previously mentioned. (This is also why the Tyco E7, C630, and SD24 Units tend to shake more than the F7/F9, GP20, or the C430)

If you have multiple Tyco PT Steamers, test run them in pairs until you find 2 that run close to the same speed, and mate them as a double-header! What worked for the prototypes can sometimes be the scale solution as well!

In all fairness, you could just mount a very short Athearn diesel chassis under the tender shell and have an "instant solution" to all of this, but where is the fun in that???


By Graves Clayton (not verified)


I just wanted to take a moment and thank you for this page. I have a Alco Century 430 Virginian that I got for Christmas in 1982 (I was 11) that has been in the attic for a long time. I recently told my kids about having some trains when I was their age and they seemed interested so I got them out. I put the Virginian on the track and basically it lit up, moved a litte and made a horrible squealing noise. This is where your awesome instructions came into play (I couldn't believe how easy it was to work on it when you have good instructions). I followed your instructions and found quite a bit of carpet fibers in the wheels and gears...guilty, all we had was carpet when I was a kid. The real culprit though for the loud squealing was the pinion gear needed one drop of oil. Now I have the engine put back together and it is running very well.

Thanks again,

By Trever (not verified)

You're quite welcome, Trever. I love comments like yours - they're pretty much exactly what I was hoping for when I posted this in the first place. Thanks for sharing and I hope that Virginian loco forms some more happy memories for you and your kids!

By Tony L.

Hi Tony,

I have a question for you...I recently purchased a Tyco Consolidation 2-8-0 Santa Fe (Tyco # 245-22) still in the original box. If I had to guess this train was rarely used and sat in a attic for 30+ years. When I got it out of the box the engine itself is in new like condition. The tender at first glance was to until I looked at the wheels.The plastic drive wheels are in bad shape (cracked and a little dry rotted I assume). I found two traction tires in the box but for the life of me I can't figure out which wheels they go on. Would you happen to have a picture or insight on where they should go?

Thank you,

P.S. Once again thank you for this website...since the time I fixed my Tyco Alco Virginian I have fixed several others as well as the above mentioned Consolidation's PT motor which is running smoothly.

By Trever (not verified)

Hi Trever,

Two of the plastic drive wheels should have grooves in them, which the traction tires fill. Should the the wheels that are on the motor axles (as opposed to the outboard, pivoting ones on each truck). It's not uncommon for those wheels to split as you see, but usually it's a fine enough hairline crack that it will run OK - the traction tires actually help since they both literally cover the crack and hold the wheel together...! Without the tires, the rails settle into the wheel treads, causing the loco to run poorly with or without cracked wheels.

By Tony L.

Hi Tony,
I have a Tyco Burlington Northern (the green "415" one) locomotive from my childhood which was recently unearthed for me, hasn't been run in about 30 years. I set up a small track for my little girl for Christmas and tried to get it to run. The interior light lit up nice and bright but the train didn't move, but I could hear it sound like it wanted to. Then a whine started to sound, then it got higher and higher pitched and finally ended with the sound of a little tiny gear spinning like mad on the power truck but no motion.
Today I carefully took the loco apart to try to fix. The problem is the pinion gear is sticking out past the main reduction gear. I can push the pinion in a little to mesh but it easily falls back out of contact. I tried prying the reduction gear out some, and it meshes as long as you don't touch it, but when there's a bump it goes back to being almost right up against the main plate. I compared it to another PowerTorque I had out of a dead engine, and the pinion gear on the Burlington is definitely sticking out farther than it is on the dead one. On the dead one the pinion gear is only about half a millimeter clearance from the face of the truck, but on the problem one it is about 1 or 1.5mm. So the teeth just miss the main reduction gear, sticking out past it. Also, most interestingly the motor shaft is sticking out pretty far too - probably out about half a centimeter past the pinion gear. I try to push it in and it won't go - but also interesting is that the shaft is sitting just find on the other side. Maybe it was an extra long shaft?
Anyway it would be great if I could repair this, the loco has high sentimental value (was my grandfather's). Any thoughts? Thanks!

By Rich (not verified)

By the way Tony I found a different way to reassemble the power truck when the brushes stick out due to the springs and make reassembly difficult. Thought about messing with the "Method B" with removing the brush plates but didn't want to mess with those. What I did was push in the brushes until they were flush, then took a piece of clear regular office tape, ripped it down the middle so it would be a thin strip, then used the tape to hold the brush back. Had a long piece sticking out the top. Then put the cover plate on with tightening the screws down about halfway, then carefully pull the tape pieces out the top. When the tape lets go, the springs will push the brushes against the armature and you're set. You have to be careful, don't press the tape down on the bushing so hard that it tears when you try to pull the tape out. But worked pretty well for me.

By Rich (not verified)

Hi Rich,

Slipping pinion gears are not uncommon, but can be frustrating. You should be able to push it all the way down on the armature shaft until it just about touches the housing, so that it makes a reliable mesh with the reduction gear. You can try super glue epoxy to hold in in place if it keeps slipping. As for why the armature shaft is long, I have a few PTs (all from Sharks as well, oddly enough) that have long shafts... it serves no purpose that I can discern.

One thought I have is that while your pinion has slipped, check how well the other gears turn. They should turn pretty freely. If there is excessive drag, that could be what causes the pinion to slip in the first place.

Thanks for the tip on spring and brush assembly! It makes sense as you describe it, and should be pretty easy. I recently spoke to a former Tyco employee who sent me a special tool they used for this purpose, and it works in similar fashion to what you describe :)

By Tony L.

I just got a Chattanooga 2-8-0, but the wiring is completely messed up. The wire going to the motor from the front truck of the tender has a longer part with the end stripped that looks like it should go somewhere but I'm not sure where, and I'm unsure of where the two wires between the engine and tender should be soldered. Could you please tell me where they should go?

By Aaron (not verified)

Hi Aaron,

When you look at the motor, take note of the two electrical terminals. The terminal closest to the rear of the tender (the coupler) should be connected to *both* of the swiveling tender trucks. On most builds, these wires are black. This motor terminal should also have a 3rd wire connected to it - probably black as well - that connects to the locomotive.

The other, forward, motor terminal will have one wire - probably red - that connects to the locomotive.

So as for the locomotive, these are somewhat tricky to work on but you can open it up by removing 3 screws: 1) behind the drivers, 2) the one that secures the pilot truck to the frame, and 3) the screw you will find under the pilot truck when you remove it. Remove those screws and you can separate the boiler from the frame without disturbing the wheels. You will then see where the wires from the tender connect to the frame. A bronze strip runs inside the frame to conduct electricity from the loco drivers, and there are two tabs exposed where the loco cab would be. If you were standing in the cab looking forward, the red wire connects to the left (brakeman) side, the black wire connects to the right (engineer) side.

You will also see some additional wires at the front of the loco, these connect to the headlight and smoke heater.

I hope that helps...!

By Tony L.

Great work, good inspiration to revive my Tyco red box F-9. CD tray motor was genius, but I thought I was the only one who used it for model RR application, in this case to power a factory roll-up door:

Video of mechanism:

By Stuart (not verified)

Not sure how well a CD motor would adapt to the MU-2 truck used in the redbox era... you might have better luck with a smaller, traditional can motor. But I'm glad this gave you some ideas! I can't take full credit for CD conversion concept though.

Love the roll-up doors, that really adds dimension to the backshop. I recall seeing a similar mechanism for a westerm tunnel portal as well. Nothing better than scratching your own solutions!

By Tony L.

I have an old TYCO Santa Fe Locomotive, 4015, and the rubber band tires are missing. Also, when I first start the engine I have to give it a push to run. Where can I get the rubber band tires and how do I fix the running problem?


By Tony Marzulli (not verified)

A "Santa Fe 4015" was available for many years and this could be found with both types of motors. In either case, the easiest source for traction tires I know of is the smallest-size "Goody" brand hair bands you can find at beauty supply retailers. These might be a tight fit on the earlier "MU-2" motors not shown here, because those wheels were narrower. You can also look for the tires formerly sold by Calumet on ebay or online.

As for the push-to-start issue, that's typical of gunk and debris in the motor, especially the armature... clean out what you can. Dirty wheels and track can also cause this.... the nudge provided moves them to a clean spot which gets the motor running.

By Tony L.