TMCC Gremlins??

Check connection from "U" post on Command base and where it's connected to track. tight???

Hold hand over engine... will it behave now?

Thanks, my first two thoughts.  No joy which is reason for post.

Can you get your hands on another Legacy Base to swap in and try it?  Perhaps the base has developed a problem.  Do any engines run as before or are they all NG now?  There has been a thread lately about tuning the base TrackLink signal.  Perhaps it was on the edge before and has not drifted past the good point?

Not sure what this means "All other TMCC locos perform as well".  Do they perform as well as they did previously or badly as weel as the two you mentioned?

I'm as confused as Chris.  Are these two locomotives the problem ones, or are all of them a problem?

If there is high humidity, dampness, in the basement, the wet-ness tends to effect the TMCC signal.  Kind of Grounds out the two outside rails, degrading the signal available, while not necessarily effecting the 18 volts AC.  IMO.   I had a similar issue several years ago when I ballasted my Atlas track.  A week or so of Elmers white glue drying and it went back to normal.  IMO.  I'd clean the track and turn-up the heat.  Mike CT

Other locos run fine, these two are the issue.  The C-420 is likely an antennae issue but now it ignores the signal completely.  It had problems in the past at selected locations on the layout and I just haven't addressed that issue yet..  The baby train master just started acting up for no apparent reason.  It just simply sputters along now when it ran just fine on Sat when everything was shut down.  There were no wiring changes, no sudden shorts, no power spikes or outages, it just woke up on Sunday in this state.  

Well, if you have a host of locomotives that run normally, and one that was a bit problematic previously, and now another one, I'd be looking at the specific locomotives first.

Pick one and chase down what's going on with it.  I'd take the C-420 and open it up and check the antenna and other wiring.  I routinely reseat all the boards and connections for an issue like this as a first step.  If all the wiring and connections look OK, the first thing I think I'd try is swapping the R2LC from a working locomotive in and seeing if this is just a bad R2LC.

The Trainmaster would be a similar scenario, check for the obvious stuff first, could be a loose connection, chaffed wire, etc.

Interesting responses.  It is winter in the northeast so humidity has been in the 40% range but I will save that piece if info for the summer.  For what it is worth, I traced back all my steps and remembered I disconnected the power strip while doing something un-related to the layout.  When I plugged the command base back into the strip the plug was in a different location.  Now this seems stupid but I unplugged the command base and changed locations on the power strip.  To my surprise everything now works.  Being the good scientist I am, I returned the plug to the original location and the gremlins re-appeared.  This power strip is going in the trash.  

So the gremlins live in an inexpensive power strip.  All locos now running flawlessly. The lesson learned here is the connection to the house ground MUST be tight.  It was interesting to observe one loco completely fail to receive the signal, another sputter, while 2 others didn't seem to notice.  It was also interesting to observe position 1 on the power strip (the one closest to the on/off switch) delivered the best overall results while position 3 and up resulted in complete failure of the TMCC signal.  This was the last thing I thought to check when trouble shooting the connections.  It will now be included in the thought process.  Thanks for the advice forum.

Glad you got it sorted out.  We had this discussion about surge suppressor strips in the past, but I guess we forgot to include it in the though process this time.

might be something to add in the  TMCC/LEGACY REFERENCE MATERIALS & MANUALS section.