Marshall: I know nothing about MTH DCS. I run only Legacy/TMCC
I agree with Mallard. Disconnect everything except track power (your transformer). Turn on track power and check the rails for 18volts. If you any wiring issues such as shorts the transformer will shut down. As you check voltage make sure you also check across the isolated junctions. By that I mean place the negative probe on an outside rail on one side of the plastic rail insert and the positive probe on the middle rail on the other side of the plastic rail insert.
If everything checks out then start placing locomotives on the track one at a time. Start them up as you normally do and see what happens. If you reach a point where adding one more locomotive recreates the problem then you may have a power issue (not enough amps). I am saying this because I had a similar issue with my TMCC/Legacy. This goes back a while since I have been waiting to close a year for a new 180W power brick to use with a 360W 20amp Powermaster. I loaded up a track with about 8 locomotives and turned on power. I can't remember if I tried to power up all the locomotives or just one. While they did not go into conventional mode the Powermaster did trip and shut down. Once I removed about 4 locomotives the system starting working properly.
The power brick is finally on its way (long story). I have the 360W Powermaster ready to go. Hopefully I will have them connected this W/E then I will load up the track and see what happens.
