# Lionel GP20 motors



## train man (Feb 23, 2009)

hi all I have one of the old Lionel GP20's that is finally starting to have motor issues as I painted the engine to represent the first locomotive I ever ran in real life I'd really not like to retire it. I've located a source for new old stock Lionel motor blocks for it but before I order these I am curious if it is possible to retrofit the engine with USA Trains GP motor blocks as I feel this would make it more reliable in the long run. Thanks for any info!


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## Stan Cedarleaf (Jan 2, 2008)

Train man... I don't think Lionel has any GP20 motors in stock. I've tried to get some other large scale parts from them and they were all "out of stock".. 

I think your best bet is to refit them with the USA GP/F3 trucks..... They're more efficient, will last for a long time and when they do need repair, they are easily repaired or replaced..


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## train man (Feb 23, 2009)

thank you for the reply! yeah lionel does not but there is someone selling them on ebay right now, but more importantly you are saying it IS possible to use USA trucks with the engine?


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## Stan Cedarleaf (Jan 2, 2008)

train man said:


> thank you for the reply! yeah lionel does not but there is someone selling them on ebay right now, but more importantly you are saying it IS possible to use USA trucks with the engine?


I personally haven't done that but it sure could be worth at try....


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## Mike Toney (Feb 25, 2009)

Be carefull! The Lionel engine is 1:32nd scale and USA are 1:29th, much larger when compared side by side. If you dont run the daylights out of it. I would just retruck with the Lionel trucks. Just my 2 cents but I think the larger trucks will look out of place. You must have put lots of hours on it to have bad motors now I ran my BN GP20's quite a bit years ago and never had issues with them, but I also regularly lubricated things. Mike


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## train man (Feb 23, 2009)

Mike Toney said:


> Be carefull! The Lionel engine is 1:32nd scale and USA are 1:29th, much larger when compared side by side. If you dont run the daylights out of it. I would just retruck with the Lionel trucks. Just my 2 cents but I think the larger trucks will look out of place. You must have put lots of hours on it to have bad motors now I ran my BN GP20's quite a bit years ago and never had issues with them, but I also regularly lubricated things. Mike


yeah, honestly I will probably go with the Lionel trucks, and I actually haven't run it that much though I can't speak for the previous owner I purchased it off ebay because I needed a GP20 and lionel is the only one that ever made one. This thing is actually quite a strange case I had it running the other day during an open house with the local club and it stopped and smoke came out from under it so I figured it must have burned up a motor. This being during an open house I didn't really have time to check things out but today I took the shell off and put the engine on rollers and discovered that the engine does in fact run in reverse but not in forward so I don't know if its necessarily a burned up motor if everything runs in reverse nevertheless I think I'll order the new trucks and go from there.


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## SD90WLMT (Feb 16, 2010)

Before just going from there by simply ordering those new trucks...

Its time to remove and or atleast separate the power leads to the motors...run separate low voltage power to the trucks such that you can swap the polarity..checking for operation in both directions at the wheels..

You may very well have electronics inside the loco that were damaged...not the motors..
Further assessment is needed to fully determine the problem here...before just running off and spending money..that you may need for those damaged parts....

If the motors run in reverse...should they also not forward...
Think ...what controls the motors? Keep looking...

Trying to help! ! Dirk


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## train man (Feb 23, 2009)

Yeah I'll have to check it out further the electronics on this thing are surprisingly advanced for how early they were produced! Testing anything but the motors should be interesting though as its all circuit boards. I suspect the issue stems from the front truck though as it smells of burned electronics.


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## bruja (Jan 7, 2008)

Train man, I repowered the GP-20 with trucks from Northwest Short LIne about 8 years ago and have had no problems. I just checked their website (NWSL.com) and they still list the gauge #1 powered trucks on page 2-14 of online catalog. It involved some tinkering with mounting them but nothing too difficult. Bruja


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## NorthwestGarrattGuy (Oct 18, 2021)

ooh i am thinking about getting a Milwaukee Road GP20 and switching out the trucks for Alco S4 trucks to make it look like it was build from multiple locomotives cause the Soo line did that with some GP30s


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## Paul Burch (Jan 2, 2008)

If you are thinking of the USA S4 trucks they are 1/29. The Lionel GP20 is 1/32.


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## NorthwestGarrattGuy (Oct 18, 2021)

Paul Burch said:


> If you are thinking of the USA S4 trucks they are 1/29. The Lionel GP20 is 1/32.


i know that and believe that would look alright


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## Greg Elmassian (Jan 3, 2008)

Interesting, the S4 trucks are a shorter wheelbase than the GP20 I think, but then the difference in scales might just work out.

I could not easily find the wheelbase of the trucks easily.

Greg


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## Paul Burch (Jan 2, 2008)

Greg,
I measured the Lionel trucks sometime way back in history because I thought they didn't look right. They scale out to 1/29. A bit oversize for the 1/32 GP20.


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## Greg Elmassian (Jan 3, 2008)

Interesting, the Lionel loco itself looks large. Their Atlantic is definitely not 1:32, it looks at home with my 1:29.

I know that Lionel is supposed to be 1:32, but I think your measurements are closer to the real situation.

Greg


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## Paul Burch (Jan 2, 2008)

Greg,
Just stumbled on this today while cleaning out old files. The photo shows three Lionel Geeps. The one in front is a kitbash that I did in the late 90's and has 1/32 trucks and sideframes. The U.P. unit is stock Lionel. You can see the difference in truck sizes.


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## Greg Elmassian (Jan 3, 2008)

I'd say that the Lionel is definitely not 1:32, and may not even be to scale, whatever the scale of the Lionel is.

From cab height, it could be 1:32, but length? hmmm....

Greg


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## du-bousquetaire (Feb 14, 2011)

The Lionel is suposed to be 1/32 scale but the trucks have a wheelbase of 9' instead of 8'. I fitted mine with NWSL wheels (still in nickel silver) and she has been running fine ever since. I lowered it and screwed the pilots to the body with a 5 mm shim, as well as installed kadees and redid all the grabs and handrails to scale. I ripped out all the electronics also. I suspect that it brings about a great deal of trouble. I just redid one of the two motors version for a friend and it is catastrophic compared to the four motors version. It seems that the rubber band and pulley system eats up too much power and amps. the wheels get dirty right away. I would do the test Dirk suggested first. By the way the atlantic is overscale about 1/30 scale. I sold mine quite rapidly. The problem with the Lionel wheels is both the fact that they are aluminum which oxidizes immediateley, and that they have oversize flanges which may bump on the spikes;


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