Help with TMCC??

Pat,

Can you temporarily disconnect the SW and connect the Z4000 to the upper loop and run TMCC successfully? Lets eliminate the SW transformer as the problem by doing this.

Al

Ground plane issue? Sometimes you have to add a ground wire nearby whenever two TMCC tracks cross one above another.

That only the TMCC unit has issues with the upper level while in command mode seems to point to a signal problem.

---PCJ

"The problem is on the upper loop  .....  the Lionel TMCC engines run fine but quit once they get half way around the upper loops. Conventional engines run fine all the way around the upper loop as do my MTH engines running in conventional mode."

When you say "quit" what exactly is happening?  Is the headlight flashing? Can you still blow the horn?  This would indicate a TMCC signal issue.  There are two sides to the signal and you could have problems with either.    To check if it's a ground signal problem hold your hand over the engine when it stops.  If the headlight stops flashing and you can blow the horn then you need to run a ground signal wire.  If the hand trip doesn't work you may have a signal return issue (outside rail).  Try a temporary jumper between the outside rail of the lower and upper loops (alligator clips work well.)  If the engine now runs you have a bad return path.  You'll need to run a new wire from the outside rail to the U post of the command base. 

Good luck and keep us informed of your progress.

I just read your post more carefully.  You say you have an SW running the upper loop.  Is the command base U terminal also connected to the upper loop?  It should be for best signal path. You could run a line from the Command Base U terminal directly to the outer rail of the upper loop. 

I do not use two transformers, so how that affects it I have not experienced, but:

Definitely the command signal; TMCC is usually close to bulletproof, but you have

a probable ground plane situation. Can you reach the stopped loco and hold your

hand - or something else - over it? If control returns, you have a ground plane issue.

A blinking (more a fluttering, to me) headlight indicates a bad signal.

However, try the jumper from "good area" common rail to "bad area" common rail

(mentioned above, I think). Sometimes this works. 

Upper/lower track levels can - it does not always; many variables - bring this issue up.