running analog

MTH has some sort of proprietary digital control system.    I think the PS2 version is older.   Maybe it does not support straight DC.    That might have been when they did their own system or AC only, not DC.   

Have you contacted and MTH tech support person?

Paul

All MTH O scale locomotives sold in a factory 2 rail configuration will run just fine on conventional DC power.  To hone in on what your problem might be more information will be needed.

What is the product number of your locomotive?  MTH factory O scale Proto 2 two rail products have a 20 prefix and end in -2.  The number on the box should be  20-XXXX-2 or 20-XXXXX-2.

You said that "When I put it on the track  the transformer gives trouble."

What sort of trouble does it give?  Are you getting an overload indication or a tripping breaker?

What make and model of DC power supply are you using?

For more info on conventional DC operation of MTH locos you might want to read this recent thread.

https://ogrforum.ogaugerr.com/topic/mth-loco-question

Paul,  Ted is definitely right on track! 

Need more information "transformer gives you trouble"?   What kind of trouble

Also curious if the loco has operated on a DCS equipped layout and if so, did you run into any trouble there?  Like Ted I was first thinking a short somewhere on the loco tripping the overload indication or breaker.   Could be in the electronics or somewhere else on the locomotive, trucks to chassis, etc.. Often there is a insulating spacer between the trucks and the chassis, or could be something like the wheels mounted incorrectly if it was converted from a 3R loco, etc... Perhaps a wire broke off someplace? 

Check the wires coming from the trucks. On some diesels, sometimes they scrape the chassis and create a "resistive short" when the insulation starts to wear through. Removing the truck and putting a little shrink tubing or paint-on insulation fixes that. At the same time, slipping a piece of electrical tape into the slot also helps.

All MTH 2-rail Proto-2 and Proto-3 locomotives will run on analog DC (sound, but no horn/bell) or analog AC (horn and bell available with standard 3-rail transfomer). Some transformers, however, use "phase limiters" to vary the voltage which creates a choppy sine wave that the engines hate. A pure AC transformer like the newer MRC, or an MTH Z4000, or the older AC train transformers from Lionel and American Flyer (put a 10-amp fast-blow fuse in line with the power) will work.

I know this is basic, but make sure all the switches are set correctly, there usually hidden behind a compartment.          cTr....(Choose the Right)