Page Updated 12/2003
Page Updated 05/2008

Locomotives That Work As Well As They Look

This is a description of my model railroad drive business. I encourage you to have a dialog with me so that we can fully discuss your interests and what I can do for you.

Custom Drive Systems

I refer to the process on installing a drive system as customizing a locomotive. As you will see below, there is much more to making a locomotive run reliably and smoothly than installing a ball bearing gearbox and a can motor.

A customized loco does the job: it runs every time the throttle is opened, it pulls a realistic length train, it stays on the track, and it looks right.

Any locomotive, domestic or imported, small or large, steam or diesel, painted or unpainted, can be customized. My drive customizing continues Jerry White's experience in providing hundreds of famous durable, reliable, hard working model locomotives, which today command a premium price because of their premium performance.

Note: please see the Exclusions section below for jobs I will not take on.

There are some folks who provide good drives; their designs and approaches differ from mine. However, there are also Some "drive experts" who are poorly equipped gear box and motor swappers who may do more harm than good.

"There are those whose only concern is cost, and there are those whose concern for quality is minimal. The former are the legitimate prey of the latter." - Unknown.

My approach to making a locomotive run well focuses on these areas:

  1. Every time the electrical circuit between the rails and the motor is interrupted, the loco will hesitate or stop running. It won't run at all, or run smoothly if it does run, if the motor doesn't have constant juice!

    I provide for reliable track to motor electrical connectivity.

  2. If it sounds like a worn out coffee grinder when it goes by, the illusion is sorta shattered. If it won't pull a respectable train or run at a realistic speed, again the illusion doesn't work.

    I fabricate and install a smooth, quiet, durable, and powerful drive system.

  3. If it runs well but won't stay on the track, what good is it?

    I ensure reliable tracking, e.g., your loco won't derail on track and turnouts that are built to NMRA standards.

  4. I ensure that the basics that, well, make a locomotive right are there: KD coupler(s), correct lights, deck plate (if applicable), air and steam connections on the tender (if applicable), etc.

Here are the details on how I approach the above items:


Electrical work is very rugged and reliable the way I do it. Connectors are installed so you can separate major pieces like the boiler from the frame without resorting to a soldering iron, and heat shrink tubing is used everywhere for electrical insulation. Circuit modules are securely mounted with a screw or double sided foam tape.

Standard constant directional lighting is one constant light in the loco front that is on in the forward direction and one constant light in the loco rear that is on in reverse. Additional lights and/or lighting effects are extra cost.

The constant lights are implemented with voltage regulators. They do not take voltage away from the motor like diodes do, so you get the advantage of full top speed. Their disadvantage is the light doesn't come on until there is 5 volts on the rails, and the loco will usually be moving by that time. Diode controlled lighting costs extra; it has the advantage of turning on the lights before the loco moves, and has the disadvantages of being more complex (higher cost) and of reducing the loco's top speed.


It is extremely important that proper operation of the locomotive be verified before it is shipped to the customer. I want the locomotive out of the box to be ready to run for many hours. The last thing I want is for the customer to have to return the locomotive to me because something wasn't right that I could have caught and fixed before shipment to the customer.

To that end I thoroughly test every customized locomotive. The locomotive is run continuously on a loop including turnouts, and pulling the heaviest set of drag sled cars that it can start for before it is considered ready to ship. The loco is run clockwise and counter-clockwise, and forwards and backwards through number 6 turnouts. It is run on 48" and 60" radiums curves. If equipped with DCC, another DCC loco is used to gently push it which simulates descending grades where the train will push the loco. Compare that testing to back and forth once on six feet of straight track that is commonly used as proof that a loco runs OK!


Each of my customized locos is identified as such by "RM" and a serial number stamped on the gearbox bottom.

Gearboxes built for some customers but not installed by me in the locomotive are identified as such by "RM GB" and a serial number stamped on the gearbox bottom. Locomotives with "RM GB" on the gearbox bottom can not be viewed as having been customized by me, nor viewed as having my "drive" in them. Note: I no longer offer stand along gearboxes.

Q and A

Q: OK, so what does that all get me?

A: You get a smooth running powerful locomotive. I use as large a diameter worm gear (axle gear) as possible. The larger diameter provides a greater torque arm for the worm, which provides smoother starts and reduces the load on the motor, which lowers current draw and decreases motor wear.

The shakedown run reveals surprising faults such as crankpins working loose, drivers working loose, screws working loose, and shorts that show up after wheels rub through paint that up to that time had prevented the short. I correct all those problems so that out of the box your loco will run smoothly, be powerful, and be maintenance free for many, many hours of actual operation.

The test train I use comprises up to 5 (depending upon how many the loco being tested can start) specially built cars that combine heavy weight with drag. One can come up with a train of all lightweight plastic cars and all free rolling trucks that can almost be moved by blowing on the end of it. For comparison, my 5 car test train takes a four pound pull (as measured by a fish scale with a coupler on it) to start.

Q: Sounds like a custom made gearbox is a boondoggle since ball bearing gearboxes are available from NWSL and some imported locos come with ball bearing gear boxes.

A: All those gear boxes are mass produced, meaning they do not approach the precision fit and quality of my gear boxes. Precision fit is important because it eliminates unnecessary gear box movement, such as the box vibrating on the axle, that causes uneven running. I make my own gears, assuring absolute concentricity which gives smoother running. Making my own gears enables me to create the gear ratio you want. No other supplier of drive systems, including all the importers, uses an axle gear approaching mine in diameter. Further, no other supplier of drives has a design that positions the worm relative to the worm gear independent of clamping action by the threads of the screws that retain the gear box bottom, i.e., the worm and worm gear positions are determined during the fabrication of the gearbox, and cannot be altered during maintenance - this ensures that the gearbox will always provide the performance for which it was designed.

Q: I've heard that Delrin chains stretch.

A: Not true. I have diesels in which the chains still sing when "plucked", and they've been in the locos for 25 years.

Ask My Competition

If you are thinking about having a "drive expert" do some work on your loco's drive, ask these questions: How do they ensure correct quarter of the crankpins after installing the axle gear - if they re-quarter the geared axle, that is the wrong answer as what is necessary is that the geared axle quartering be identical to the other axles, whatever their quartering may be. Do they ensure the gauge of all wheels is correct? Do they file rods to eliminate binds - run the other way if they do. Do they remove the wobble in all driver wheelsets, and if so, how? Ask for a description of their test track and their test procedure, and then compare it to mine.


My drives are warranted against failure for as long as you own the locomotive. Failures caused by faulty maintenance or abuse are not warranted.


I have learned from bitter experience that fitting custom drives into some locos, and some drive system modifications can have a very high cost.

This is because the loco may have poor assembly quality, or poor design, or the wrong materials were used when it was fabricated. Modifying factory (Original Equipement Manufactured - OEM) drives can become a rat's nest very quickly, as fitting the new part or subassembly into the system that the manufacturer developed requires careful planning, measuring, and fitting, and the design and fabrication of the OEM system may be such that making modifications to it is very difficult or requires fussy fitting, all of which increase cost.

Note that on the other hand, some drive system repairs (contrast repair with modification/enhancement) can be very simple and inexpensive.

Some locos are of such quality that spending the money to customize them may not be warranted; another way of saying it is that I don't want to work on them and you wouldn't want to pay what it would cost if I did work on them. Locomotives imported by International, NJ Custom Brass, and some locomotives built from scratch or from kits may fall into this category. If you have one of these locos we should discuss it before you ship it to me. Upon receipt I will perform a thorough inspection charged at 1/2 my normal labor rate to determine whether work in addition to that described above is required.

If you have a drive system repair chances are it will be low cost and done with a quick turnaround. If you want a drive system modified, we need to carefully evaluate the cost-effectiveness of the change(s) you want. In any event, we should talk about what you want done. Most times a repair can be evaluated over the phone. I need to see the drive system that you want modified before I will take on the job. If the modification involves modifying die cast parts such as gear boxes, I strongly recommend that you consider replacing the drive system instead.

Thank you for your interest. Please contact me if you have any questions.


Interested in learning more about 2-rail O scale? Please visit the O Scale Kings web pages.

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