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This is my first model train I have built,(and maybe my last McKeen Car) and I would like some help with Ideas on how to power it.  I purchased a motor used in the engine in the starter sets made by Lionel.  I thought about buying a worm gear and mounting the motor vertically, but I have never done this sort of thing before and  one problem I have is that it has to be able to run on 036 track.  Currently it does, but I don't know the best way, because of no experience in this field of model making.  If I have to, I can cut out the sheet metal around the front king pin, and add a support to hold the king pin, but I am trying to stay away from that.  As you can see I experimented with a rubber band drive, yes I made that up, but sometimes as the train hit a curve, the rubber band would come off. 






Images (4)
  • front truck left side
  • front truck right side
  • underside of the motor car.
  • top with the smoke and fan units, and a the head light.
Last edited by Madison Kirkman
Original Post

Getting/fabicating the correct front truck has to be one of the peaks to be surmounted with these cars..great that you have done that.  Maybe a Marx mechanism that, as in

their cabbed diesels, turns with the front truck is workable, after engineering a gearing to drive the front axle.  Or possibly powering the rear truck, where complete mechanisms, with truck frames that can be modified, can be used.



I meant to add...since you have the difficult to form body and unusual front truck

fabricated, you are over the big humps.   I hope others on here with more experience

powering creations, can offer mechanical suggestions.  An old choice for rear truck

power was that chain driven truck offered by Walthers for their gas electric kits.  There

must be something more modern than that, and applicable to three rail, out there.

Very good to see you making the attempt to create a reasonable representation of the unique drive truck of the McKeen car.  Just plopping a body on a diesel drive is really an visually unsatisfying compromise.


I'll reinforce the the Old Goat's suggestion that you look at the NWSL and Q-car for powering ideas.  From NWSL you could get a Magic Carpet drive unit that might be built into that same truck w/o taking up excess space that would also fit under the floor neatly.  From Q-car you might be able to get a geared axle transmission unit with can motor that you might ber able to build into the truck.  Whether to put these into the power truck vs. the trailing is another decision to be pondered.

My only problem is the price, I don't want to spend that much money, is there a worm gear I can purchase that, with a vertically mounted  motor, I can run the train at regular speed?  Also, I want this to be able to run on 036, so I have to have a motor less then an inch wide, an inch and a half long, with the axle one C.M. in from the back and height doesn't matter so much.  All I need is either a worm gear that works with the starter motor, or a gear box.  I tried making a gear box out of sheet metal but it didn't work well.  If you have any ideas about making a working gear box, I would like your idea.



HF does not sell O scale was just a suggestion for ideas.  You could contact him and inquire about a custom drive.


Also, check the Grandt Line Products website.  They offer transmissions that might work for your project. 


One of the direct style gearboxes from NWSL should work.  Dave at NWSL should be able to help as long as you provide him with all the details and measurements.

Last edited by Old Goat

I looked at Q Car, NW Shortline, and Hollywood Foundry (which last went up to, but not beyond, S scale) websites, and nothing much has improved in the decades I have been looking for power for 1/4" 3 rail creations. (when I began, I was blown off by one of the above, which is now under new ownership, for wanting a three rail drive train)  On this site I have learned I am most certainly not the only person with such interest.  Bowser was only the source I found, for single and two truck traction chasses I could modify...(I am not sure they are still available from Bowser).  Q

car had one, that I saw, truck side frame stated as used by gas electrics.  (Walthers

and American Car Co. have made O scale gas electric kits....Walthers did provide

a power train).

There is no model train show that approaches the size of the three rail dominant York

meet, so....why is three rail ignored by these manufacturers?


I would suggest a north west shortline gear box on the larger wheel axle...under drive and the motor in the floor with a flywheel. Being that the front truck wheels are different sizes you'll probably never be able to drive them both the same speed.

An amusing totally old school idea...and this is waaaaay left field, is the old athern HO scale rubber band drive system. You'd need a drum nearly as large as the large drive wheel and a front to back running shaft to drive it off of- a slightly twisted band connecting them together.

Originally Posted by Old Goat:

One of the direct style gearboxes from NWSL should work.  Dave at NWSL should be able to help as long as you provide him with all the details and measurements.

This is probably your best bet in getting a gearbox that will fit into your drive truck powering the front wheel.


You might be able to use this from Q-car but it will take work and it's ~$100

You'll have to change the wheels - Q-car does not have anything to do with 3-rail - no interest in that market and has more than enough business; there's currently at least a  3-6 month wait for a drive truck and trailer.

I don't know, most of these items will not work, although the Q-car one looks plausible, I think the 3-6 month wait is not the best.  I find it hard to believe that the part is so expense, considering that all there is a brass gear box, motor, and an axle.  I think I might try a Marx motor.  Precision scale should have a free downloadable catalog, if they want business like me.


I had an idea by the cylinder drive.  I would have a small pipe that is above the front axle, and would be powered by a motor width wise in the engine.  By doing that, the rubber band would always say vertical.  Although it would take some time to build, I think that is the best bet.  I have pulled apart both a VCR and a R.C. Car, but I don't think either have a good gear system.
Originally Posted by handyandy:

I wonder if a belt drive could be rigged up from an old VCR drive?

Have you looked at all the drive parts available for RC cars?


Awesome job on the McKeen car so far BTW.


Very nice job. If it were me i'd let the front truck be the dummy and consider powering the rear one which from the photos i've seen appears to be of a more traditional configuration with equal diameter wheels. Depending on the wheelbase needed i'd consider the power trucks used by Lionel on their RS-3's or the ones used by KLine on their S-2's. If either of those were of the correct wheelbase  you could simply grind or sand the side existing plastic side frames flat, and then using scraps of plastic and brass build up the detail of the side frames to replicate those on the McKeen cars on the flat surface you just created. If neither of those offered the correct wheelbase i'd search for an existing truck of the right wheelbase(probably from a passenger car with plastic side frames), and use the same treatment as above for side frame detail; then get the keyhole style can motor mount and motor assy. from any small "China Drive" loco; then send the truck and motor assy. to Frank Timko for gear installation on the axle. A piece of sheet brass with a key hole cut in it  and then screwed to the floor will serve as the mounting plate for the vertical can motor. I've scratch built a few projects using both these techniques. The drive of any project of this sort is always a problem, but why compound it by making that unique front truck the powered one, and why try to "re-invent the wheel", so to speak, if you can use and existing drive unit? Finally, i've tried the Magic Carpet and similar HO intended drive units and found they lacked the power needed to handle the weight of an O gauge loco.

Good luck and feel free to contact me by email if you have any more questions.



I just checked Fleabay - search motors under O Scale trains, pages 1 & 2 have some possibilities --this is what i'm thinking of;hash=item232ea0da92 - Found on the second page.


Hope this reference doesn't violate any Forum rules

Last edited by modeltrainsparts

Because the real McKeen Cars almost never hauled more than one trailer, ever.  So I don't need any more then the power to get it up a fair grade.  Also, it would be a lot harder to power the back truck rather then the front.  I have a exhaust pipe which was such a tight fit in between the wheels, that to make the 036 curve, I had to pinch the pipe in able to make the turn.  I don't think I can power the back wheels. 

In the photos i've seen the only part of the exhaust pipe that's visible is from the rear. Sometimes in modeling we have to make compromises and eliminating an almost never seen piece of underbody detail in favor of a simplified reliable power unit is common sense to me. Those HO power units will NOT work. If i can find the one with NWSL gears, etc. in my junk box i''l sell it to you for $10 so you can see for yourself!


I don't always want to run a second car behind, and the only trailer I would use for that, is a trailer that I already bought the trucks for.  I was looking at a k-line locomotive I have, and I noticed the worm gear has the same gear spacing as Lionel, so I think I will purchase a k-line replacement worm gear, and mount the motor vertically.  I would have enough room for the motor inside the hole in the floor.  I would have to then make an arm attachment from the top of the truck around the king pin, and up inside, enable to hold the motor.  Doing that, I would power the motor car like every other, and I would have not compromised any detail. 


What do you guy think?  Is there any problems you guys could see?

Yes, three immediately come to mind: 1) The tolerances between a vertical pinion gear and a horizontal ring gear are quite critical; do you have the tools to properly align these and are you familiar with the use of Prussian Blue and lapping compound? 2) The vertical play becomes more important with a leading truck opposed to a trailing one in the prevention of derailments, are you planning on building in a means of adjustment to get the amount of play exact? 3) The entire motor/drive/truck assembly will need to be mounted in a way to swing to horizontal tolerances of 1/32" or less (while holding this tolerance over all vertical motion) to prevent derailments (esp. through turnouts and while reversing). Do you have the tools to accomplish this?

I simply don't understand why you seem to want to further complicate this project by powering the front truck!?!?! if the reason is to adhere to the prototype then power it with a miniature gasoline engine!



I do have the tools that can allow me to create a strong metal arm to hold, and adjust the position of the motor.  This arm is only attached to the truck, and will move freely up to down and side to side.  I don't want to compromise the back truck because the motor in the front allows for a partly lit interior, and the fan and smoke unit could be moved to the baggage section.


I pushed the motor car around curves and on a 036 curve, it works fine.  I will have to add a little weigh for added traction, but what I wanted to ask on this post is if there is journal box or something like that would make completing this easier.     

Madison, did you follow mwbs suggestion of looking up under drive units/carpet drive yet?..the flees aren't ready for release and haven't been for a while{darn it}.


You will note that the carpet drive is really 2 rail friendly, but that hardly limits it to 3 rail useage by using another truck as pick up leads for powering it.


You could get lucky and mesh the gears correctly as you last mentioned, but you could easily not get it right and toss you time and investments away in a few's a fairly precise thing to set gear mess and gear load correctly...bachmann has been trying to get it right for years{lol....oops}. If money is tight for you, do it right the 1st time even if you have to save for it. This carpet drive is truck hung, meaning you will need to support it via the truck side frames.

Another source sans motor is here-

You could mount that verticle with a motor depending on given height or lay it horizontal and use universal couplers to a motor.

If the 2 above don't appeal to you go with using a power truck assembly for the rear truck with the same axle spacing.


I admire your tenacity so far, but the "how do I set my own gears" thing might leave your engine sidelined.


I have used twin magic carpet drives on a G scale{boo-hiss, wrong site, I know} electric engine and it went along very nicely, but don't expect more than 1 spare car attached after that - and you'll want to keep that trailing car light just in case.   

Madison, i too admire your tenacity, but.....

Did you check out Ebay and view the listing i referenced last night - only $16.00 delivered.

As far as lighting the interior goes, LED's attached to the roof will do the trick, and can be installed only over the area you want lit.

How does the smoke unit compromise the back section which is the passenger area?

When i built my first scratch built loco (a PRR O-1) i found out very quickly that gently pushing it around the track and through a few curves was a lot different than running a powered unit over several hundred feet of track and through a few turnouts. This was a reality check and resulted in me sending the chassis and power truck to Frank Timko for proper re-powering.



I have bought Lionel trains from the EBay guy before, but I don't want to have to cut a truck in half, rather then just buy a gear box, like Burlington Route added a link to.  I think however, I would not have enough room for the gearbox the B.R. told me about, because it would have to turn it 90 degrees.  I think that that would be my best bet, but a little modifications.


Bob - Burlington Route: This is the reference to a truck assy. i made earlier --

"I just checked Fleabay - search motors under O Scale trains, pages 1 & 2 have some possibilities --this is what i'm thinking of;hash=item232ea0da92 - Found on the second page."

This was made with the understanding that the rear truck would be powered. i have a feeling the wheelbase would be pretty close to the rear one on the McKeen cars; unscrew and remove the coupler assy; grind flat the plastic side frame detail; build a prototypical looking side frame detail out of scrap plastic and brass and glue it to the power truck. Job done!


Madison -- The truck i referenced on Ebay was meant to be used as a complete assy. for the REAR. But you seem to like doing things the hard way in spite of the decades of scratch building experience that myself and others here have offered you in the way of suggestions. In the same search on Ebay on either page one or two were some gearboxes similar to NWSL ones; did you bother to look at those?



Originally Posted by Madison Kirkman:

I have bought Lionel trains from the EBay guy before, but I don't want to have to cut a truck in half, rather then just buy a gear box, like Burlington Route added a link to.  I think however, I would not have enough room for the gearbox the B.R. told me about, because it would have to turn it 90 degrees.  I think that that would be my best bet, but a little modifications.


"Rookie"...I'm pokin fun at ya here...yes, the gearbox will have to be 90 whether you put the motor facing straight up or on its side is up to you and your projects clearances...going to left field and splitting the difference you can 45 degree the motor too.  Your chassis/floor will need a hotdog type of cut out to clear the gearbox swing whatever it's orientation/angle and a strong pivot point from the opposite end of the gearbox...trolley guys do it all the time...{with their pole sticking up though}.

The easier way would be to find a twin axle power truck and put it on the rear truck, then all you'd need would be a single pivot point and a hole for the power leads{"most" have a center rail roller to tap off of}. You'd just have to find one with the same, or close enough, axle spacing.

Originally Posted by Madison Kirkman:

... but I don't know how to interchange the gears on a truck.


"Don't" unless it's to a matching gear replacement. "Tolerances" change with different gear sizes! A given power truck is manufactured with the needed gear tolerances for what it came with from the's not so easy to just change gearing in any power truck unless it's the same thing as it came with...or I would've changed mine eons ago for slower running!


BTW- what is the rear trucks axle spacing- center to center...just curious?! Scale feet or real time inches- either measurement is fine. 

Last edited by Burlington Route
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