I recently picked up a nice looking SW-8 in Penn Central livery. The engine is really nice and in good condition. It has the loco-sound system installed.

I'm having trouble with the engine running smoothly over my 027 switches (5121,22). The engine will briefly loose power and hesitate while on the switch. The power cut is not enough to drop the board into neutral.

I've tried removing traction tires in various configs but nothing improves this condition. I checked both pick ups and they are both pulling power from the rails.

The engine runs fine on track without turnouts.

Any advice out there?


Videos (1)
2020-02-29 07.10.47
Last edited by RSJB18
Original Post

Bob, it could be the spacing of the rollers producing a quick short going through the tight switch......Paul 2

I had considered that Paul. I've tried to watch it over the switches but inconclusive at this point. I would expect that if one roller lost contact the other would still be OK.


PS- the engine is rated for 031 so I'm no too far off.

Haven't noticed that happening. I was watching the wheels closely when I was experimenting removing traction tires and I didn't notice anything unusual.

did you try cleaning the track and the wheels on the engine, you have older track and it looks tarnished! Dremel tool with metal disk at the end would work perfect cleaning the engine wheels and the track ! also did you check over the engine for binding wheels or gears not meshing smoothly ! is center roller worn with a grove in the roller and did you lubricate the roller!


Last edited by Alan Mancus

The engine was fully serviced when I bought it. It was very dirty. Wheels rollers gears etc.. 


Track was cleaned to rule it out as a cause.



Images (3)
Last edited by RSJB18

How did you check both pickups pulling power?  Could be a broken pickup with internally making and breaking especially in turns, could be poor ground from terminal screw.  Could be corrosion inside pickup roller.  Are both out side rails grounded?  If it runs fine on all sorts of curves and straights, it may just be the geometry of those switches and the engine.  G

GGG- when I serviced the engine I had jumpers clipped to the roller bracket. I tried each independently and they both worked. I pulled the pick ups and cleaned them both after the issue arose, no difference.

I have 036 fasttrack that I use at Christmas. I'm going to set up a loop with a switch on the floor and try it today. If the engine works then it's track related. I do have other MTH engines and they cooperate with the 027 track. If the same issue persists then I'll have to dig deeper into the trucks and wiring. I do have two 042 switches on the layout and the engine does the same thing on them.

Here's a video I shot after repairing a broken speaker wire.

Thanks- Bob


Videos (1)
2020-02-23 16.37.26
Last edited by RSJB18

So I set up some fastrack this afternoon to test the loco on a different track system.

Results are inconclusive but its definitely an engine related issue as I see some of the same symptoms on the FT as I do on the layout. The problem is most evident on switches.

I did determine through this additional testing that the issue seems to be with the front truck loosing either power or common. I'm not familiar with what is involved with removing a truck so since I bought it recently I'm going to contact the seller and see what they will do.

Here's a brief video of the test. Sorry but trying to hold the phone and run the transformer at the same time is challenging. Again, the brief power interruption is not enough to drop the engine into neutral.


Videos (1)
2020-03-15 15.40.06
Last edited by RSJB18

Are the screws for the terminals on the inside of engine tight?  Good ground on front truck?  If it is not the pickups them selves, I usually remove black ground screw and make sure not coated on underneath.  Scrape with razor blade to ensure 0 ohm continuity.

I do find engines that the corrosion on the pickups cause issues and a new set of rollers fixes the jerky motion.  G

I checked the two screws on the trucks with the red and black wires, I didn't pull them off but loosened and re-set the screws.  I also made sure the plugs were seated properly on the boards.

I did notice some grease on top of the trucks and am wondering if it was over greased and it's causing the bad connections.

I'd pull the trucks and clean them up but I don't see how to remove them.

Thanks again.

Last edited by RSJB18

I contacted the seller and will be returning the engine to them for repair.

Thanks to all who commented and provided advice. This Forum is the best place to go for information.


I shipped the engine back to the seller (Trainz) early last week. I got a call yesterday that they were able to diagnose the problem and repair it. As @GGG had mentioned, the pick up rollers were not making good contact with the center rail and appear to be the cause of the hesitation. I did not speak to the service tech, but he left a long voicemail stating that he cleaned and lubed the rollers and it appears to be running good as new. He mentioned that he used a oil that also improves power conducting....anyone know what it is?

I did clean the rollers several times but now realize that I never lubed them. Chalk up another one to "learning experience"

I'll post a video of the hopefully improved operation after it get it back.


Got the loco back the other day. Unfortunately despite what Trainz told me the engine still hesitates. Maybe not quite as bad but....

I'll try a new set of pick ups as @GGG suggested and see if that helps. I'm going to keep it because I like the paint job, and continue to fiddle around with it. Not a whole lot of cash into it so it'll be a project.


Last edited by RSJB18

Bob, MTH went to four pickup rollers (a pair on each truck). I assume they did this because of problems like you are experiencing. I wonder if you could install the twin-roller pickups on your SW8? I believe they made the change about when 3v PS2 was released.

FWIW, my PS# SW1500s (4 pickup rollers) never hesitate no matter how slow I run them through Fastrack track switches. To be fair all but one is O72 but my one O36 track switch works flawlessly as well.

That's a good idea Lew. I will have to check the dimensions. I think one or two of my other MTH engines have the double rollers. I doubt they changed the truck design, just the roller, so it might just work.


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