MTH GP40 diesels lose power crossing switch track

Interesting

Do these have batteries or BCR?

When you checked the track for power

did you test all powered points ?

It’s possible the pickup rollers are losing power as they pass the “gaps”…

I’m having similar issues with some MTH turnouts…

and it really sucks, because I haven’t had much motivation-due to surgeries, to get into the train room, so when I get a little time and motivation together, having a “glitch” takes away the fun.

By batteries-do you mean in the engine? If so yes.  My next step is to replace them and test. Tested power on switch when engine stop but looks ok. If you look at the image, there is a roller in contact with the hot side of track when passing threw switch. I have 10 switches on that line and only 1 is giving me issues. I'll send another post when battery is replaced and tested.

Check the continuity of the outside rails.  If one of the rails is not providing an electrical return and a traction tire is on the good rail you will break the electrical circuit causing the locomotive to stall.

Tom

Are the Ross switches set up for non-derailing feature, aligns the switch when the outer wheels reach a point on the switch if not aligned correctly?

Adding to Tom Densel, what is up with what appears to be a gap in the outside rail to the left of the picture?

To check if the connection problem is with outside rails, I would try to find a place to put an alligator clip from outside rail to the frame of the engine.

There is a small possibility that the center rollers on the right side are getting nothing, and then on the left side, something going on with that dip in the center rail.

The switches are setup for non-derail. I went from outer rai (rail not using derailing isolation rail)to engine frame and engine did not stall.  I ran it threw again without connection and it went threw fine. Next time it stopped so I reconnect the wire and it started back up.  So it seems to be a grounding issue. Not sure where to go from here but I'm going to check continuity from front to back.

On more than one occasion I have had the paint or black oxide on the frame of a powered loco cause problems. I bought a used K-Line TMCC EP-5 that ran like absolute cr@p, and the only thing it needed was the wheels cleaned.

Off hand those wheels and rollers look fine.

Thanks for suggestions- I hope to get time this week to work on it.

@Doug Bo  a little late to the party, just to add,  since all of your other engines run through the switch properly, then it must be something with the engines. Physically turn your engines around on the track and see if there is any operating difference. I have heard some MTH engines connect to ground only on one side. This has to do with engines which have the switch for 2 rail and 3 rail. With the wheel isolation you would lose the neutral leg as the engine enters the isolated anti-derailing section. The idea is the neutral connects through the wheels (connecting the outer rails) to make the connection to activate the anti-derailing feature. If the wheels are isolated the connection cannot be made.

I found this topic below, but I have seen others, odd search criteria to get relevant hits. In those threads people have talked about removing the switch and permanently connecting both sides.

FYI  @1drummer  sounds like you have a similar issue.

2r/3r wheel isolation  OGR thread

(if you have the capability to run 2 rail, the wheel axles cannot electrically connect through the wheels or you would get a direct short.)

The other is to remove the anti-derailing and provide neutral to both outer rails. I got rid of the wiring on my early layout because it was so small a car was always on the switch and the motor would buzz. Not a good idea because that will burn out the solenoid.

Thanks to everyone in this thread. I did flip engine around and it seemed to have no problem. (I should have left it at that, but I didn't) I put engine on work bench flipped over and removed wheels to clean. I figured since I had wheels off, I would change traction tires, After changing traction tires and cleaning  wheels, I put it back on the track to check. It made it to the 1st switch track (which wasn't the one I had problems with) jumped off rails and tripped breaker on MTH Z1000.  I checked the engine to see if the traction tires were installed on wheels correctly. As far as I can see. they are. I put engine back on the track, and it is dead.  I hear the speaker making a static sound after about 10 sec. on powered track. I removed engine from DCS and tried to reinstall.  It does a search them displays  RF Out Of Range. (locks up remote and have to remove batteries to get it back) I put engine on a single isolated track and I was able to install it on DCS. The engine is not acting correctly (loud volume- erratic motion forward and backward).  I did notice that the axles   were isolated (to run as 2 rail -Engine is PS2) I'm going to open up engine again to check connections and test. I will keep you posted.

Doug - there is an ancient engineering adage "If it ain't broke - don't fix it."  I hope the derailment did not blow the board. While in there you may want to switch out the battery for a BCR. The PS2s have 2 types of batteries - one like a nine volt battery, the other like an old portable phone battery with the small pin connector. Sometimes a low battery can cause that type of operating problem. If its a board - it just got expensive.   Other potential cause, if you pinch a wire when putting the shell back on that can also cause problems. Make sure they are not pinched.

Curious - when you said remove the wheels - what did you mean? Did you physically pull the wheels off the axles?

By remove wheels- I meant removed axel.

Checked battery- It's an old one. Voltage is 2.5  With the shell off, can I hook an MTH 8.4 battery up to connection to verify?

I just got rid of all my old MTH Batteries otherwise I could take a photo of the options.

Early PS2 used a White battery similar in shape to a 9v. Those are very troublesome - get rid of them. I blew a board because of one. Too much in a hurry to replace before testing.  You can use a 9v battery for testing only. The replacement is an MTH 8.4V rechargeable battery usually green. Maybe that's what you have?

Later versions of PS2 went to a lower voltage battery (different board) which looked like 2 small batteries shrink filmed together. Those put out about 2.4 volts and had a different power connector and often were blue.

The system batteries are not interchangeable.  I run my engines all the time without the shell for testing.

The battery installed is shrieked wrapped in blue.  It's output is 2.4. With the shell off I hooked up a green MTH battery and tested operation. The volume is load and staticky. I can bring it down but static remains. I can startup and shut down.  Forward and reverse work but speed control is not right. With volume off I can hear the motor turn on/off with smoke-but no smoke. After a few forward and reverses it just stops. I think something fried when it went off rail.

Doug something is odd. please post photos of your batteries. The blue battery has a completely different connection than the green. Unless you cut wires and splice they are not compatible. Nor should you attempt to mix batteries.  Also what is the model # of the engine?

Does your loco have the Proto-3/2 feature?  If so, I think @ScoutingDad nailed the problem with his first response.  You are losing the ground side of the circuit because the wheels are isolated from each other.  If it has Proto-3/2 and you never intend to run it on 2-rail track, I would get in there and make sure there's a good electrical connection between all wheels and the loco chassis.  Once you've done that, I think your original problem will be solved.

I attached 2 pics of battery setup - Original and MTH attached (I had to use (volt battery connecter to female end of plug) Either way train not running correctly. I think when it jumped track it shorted something out. And yes @ScoutingdDad did nail problem. The engine is running Proto 2 and there's a switch for 2 rail/3rail operation. The axels are isolated. If I get it back to original operation, I will make sure there's a good electrical connection between all wheels and the loco chassis. Like PopEye said "leave well enough alone"

Doug - thought I was clear - you cannot mix the batteries. The blue battery is supposed to output only 2.4 volts. The green outputs 8.4 volts. Not a good thing to put 8.4 into a 2.4 board. Only thing I can say is put the blue battery back in and see if you can get it to work. That board operates on 2.4 volts.  You should try to do a factory reset if you have DCS. I have never been able to get the sequence of button presses to do a reset. Good Luck ...