TMCC Shortcoming

[luther_stanton]

I finally had a chance to spend some serious time running my new TMCC Lionel Lines Berkshire and I realized a serious short coming of TMCC. Twice in the span of an hour the Berkshire “lost TMCC signal”, reverted to conventional mode and took off at full speed with 17 volts of track power.

The first time this happened it created a mess as before I could stop it, it slammed into another stopped train sending cars flying. The second time I was able to hit the halt button on the CAB-1 prior to any impacts.

I am a little put off by a new engine doing this and I am not sure what to do. Two other TMCC engines (one Atlas and one Lionel) will sit powered up all day long and play well with others. I now operate with one finger on the halt button in anticipation. It happened at opposite corners of the layout so I do not think it is a wiring issue – and other engines are fine.

After this happened, I started thinking about the actual design of TMCC. I think it is a less than ideal design – actually a darn poor one – that a loss of signal causes the engine to revert to conventional mode and take off at full speed. A signal loss should simply cause the engine to become non-responsive. Perhaps a switch to specify whether you are operating in command or conventional mode should be used instead of assuming no command signal is the sign that you want to operate in conventional mode. I was reading a book on 1:1 scale signaling where they were discussing the fact the signals and operating rules today are created so that a burnt out bulb or malfunction will always indicate the least permissive access. Definitely a rule we should take to heart!

I am also setting up all of my sidings with “optional” power so I can disconnect them from the power source in order to “park” engines I am not using. I can have power on to pull the engines in and out of the siding but once in I can cut power to the siding. This will help to ensure there are no more unscheduled departures [:)]

Perhaps TMCC 2 will consider this….

- Luther

[nblum]

When a TMCC loco loses signal it stops. Your loco is doing something else and is not working properly.

[Roger Bielen]

I'm having a like problem with a Hudson that I've had for a few years with no problems, none of my other engines is acting up so I've eliminated a system problem. The headlight stays on solid even when having the runaway problem. All the boards inside the engine are tight, etc. I'm thinking maybe a board is starting to go since it seems to be ok after it warms up. I keep a passenger consist attached to keep it from runnig away.

[Anonymous]

If a locomotive starts to lose signal, its headlight begins to blink rapidly. If the signal loss persists or worsens, the engine stops. For a loco to revert to conventional mode, it has to lose track power for approximately .2 seconds and then have power restored and not see a carrier signal for an additional .2 seconds. If the .2 seconds lapse and it still doesn't see a carrier, it will come up in conventional mode and be in neutral. For it to run away, it will need to have power drop again and then restored to cycle the electronic E-unit to go into forward.

Your loco may have a bad RL2C receiver board or your command base may be operating at a frequency slightly offset from what the engine's reciever expected to see.

BTW, ALWAYS keep track of the HALT button and be ready to hit it, that's what it's there for.

[trigtrax]

I am a little put off by a new engine doing this and I am not sure what to do. Two other TMCC engines (one Atlas and one Lionel) will sit powered up all day long and play well with others

Since your other engines work the problem may be the antenna or front end of the receiver in the Berk. You've got to open it and check for loose connections.

[Anonymous]

I had two diesels that did this one was lionel and the other an atlas engine. The cause was a bad connection on the rl2c board. The boards were loose. I pushed them them on firmly and havent had any problems since.

[ChiefEagles]

QUOTE: Originally posted by macaste

I had two diesels that did this one was lionel and the other an atlas engine. The cause was a bad connection on the rl2c board. The boards were loose. I pushed them them on firmly and havent had any problems since.

Especially if shipped by UPS, Fedx or USPS. They drop them and slam them around. I've found boards loose on lots of engines. Good luck.

[luther_stanton]

Thank you all for the insight / suggestions!

I removed the shell and everything seemed tight as I double checked the connections. It looks like the smoke unit was not completely lined up with the stack on the shell and there was quite a bit of smoke fluid / residue on the front truck and frame. I never added more than four drops at one time and only added fluid twice in two hours of running so I do not think it was overflow. I did bend the smoke unit mount some to get a better alignment and cleaned everything up. There seems to be a lot less smoke coming from the area of the cylinders / front truck as well.

I have had almost two hours of running since with no more “take off” incidents.