MTH engine keeps restarting

You mention "first layout."  This to me indicates the tracks are either new or may have been packed awhile.  The tracks may have a film on them.  Try cleaning them with denatured alcohol and see if that makes a difference.

Yep, tracks are new, tried on one set of Atlas and one set of Fastrack.  Another engine I have seems to work fine on the tracks (PS3 southern pacific daylight), but I will definitely give it a shot!

Are the engine wheels and pickups clean.  Are the pickup screws tight?  May need to open up and see if a connector has come loose, or a wire nut on the AC input to the boards.  Those would be easy issue if this was just a shipping issue.  If this is NOS, try charging the battery also.  G

Dean, by grandson had a layout with new track.  I loaned him some locos.  When I got them back, they wouldn't run right.  The rollers were all gummed up, from some kind of stuff that was on his track.  That's why a said to try cleaning it.  If that doesn't work, try GGG's suggestions.  He knows his business.

Thanks for all the info guys.  So far its still occurring, but here is something new I noticed. If I turn off sound... it runs fine in both DCS and conventional. When I turn sound back on the speaker garbles and the engine turns off. I opened her up but didn't notice any bad connections.  

Try replacing the speaker.  If a speaker is going bad it can short.  When it shorts the Power Supply shuts off and the engine will shutdown, but than restart.   G

Also inspect the speaker wires carefully, they could be shorting to the frame and this will kill your sound amp. On PS2 that can be replaced, PS3, doubtful, it's a one board build.

I have not seen the engine insides or its wiring harness so off top of my bald head, Before changing speakers, could the speaker be un-plugged Or unsolder speaker wire(s) then try again? .

Is it worth the few bucks for a speaker to risk the sound amp?  You needn't get an MTH speaker.  They are cheap enough.

So far I haven't seen any issues with the wiring.  I just got back from a trip to the local hobby store and have a new speaker to try later tonight.  There was a lot of flaked metal on the one I took out so hopefully this will do the trick!  Will post back soon with results.

Well the flaking speaker is a know issue for early 5V systems with the 16 ohm speaker. So it is possible.  G

Just replaced the speaker and tried it out..... FIXED!  Works like a champ now.  Thanks to GGG and all that provided info on this issue.  This is a great forum and I have a feeling I will be posting many more problem, and hopefully contributing to fixes, in the years to come!  

All I have left to do is test out switches, accessories, setup scenery, and get it all working under the tree for xmas.  Will post some pics once I get it all done.  Thanks again guys - Happy Holidays!

Glad that fixed the problem.  Though weird that the speaker could cause the engine problems.  At worst I would suspect the sound chip to burn out from the speakers defect.

Think of it like an old car if the ignition power to the coil fed your radio.  If your radio had a problem and caused the voltage to drop, you would start to have ignition problems because there wasn't enough voltage to power the coil.

Glad you got it fixed.  G

I've seen speakers do a number of things, and I've also recently seen a speaker short that really toasted the board set, not just the audio amp.

If either 5V or PCB ground get shorted to chassis ground you have AC voltage applied to both the Power supply and the processor.  This normally toast about 3-5 components on each board.  Power Supplies can be repaired and I have even restored the 5V side of processors, but the 3.3V side usually is unrecoverable.

Just repaired a forum members train where the blue (PCB Grd) of the volume pot was pinch to the chassis.  Audio amp toast, even had a hole burned in the 3.3V regulator.

Power supply was fixable but I had to replace 4 components.  G