TMCC Direct Lockon Short Circuits

[Roger Bielen]

The derailer circuit is essentially "shorting" the system and may be causing a spike that the lockon senses. As chuckn mentioned the lockon is much more sensitive than the ZW.

Try modifying the switches to aux. power and see what happens.

[RockOfMaine]

It happens with both switches, and both directions. The lockon shorts as soon as the derailer circuit is completed by a set of trucks. I can force it by simply hand rolling a boxcar into the switch.

[Anonymous]

The locon is supposed to provide very fast protection to protect the sensitive electronics in modern loco's. O-27's usually pull power from the track and the internal wiring may be contributing to your problems. You can modify the O-27 switches to use auxiliary power like the O units do.

[Anonymous]

Does this happen for one switch or both switches? Also, does it happen when you throw the switch in one direction or both directions? One possibility is a shorted coil in one or both switches. Another possibility is that the powerhouse breaker may be too sensitive.

Daniel Lang

[RockOfMaine]

I'm wondering if anyone else experiences this: I am building a TMCC controlled train layout. I have a 180w Powerhouse and a TMCC direct lockon. With a simple loop it runs my lash-up in command mode just fine. I then added two O27 lionel switches (non-derailer style, which automatically switch to the right incomming diretcion.) to created a parking yard.

Now, whenever I throw the switch or run a train thru the switchworks the lockon must sense a short as the circuit breaker trips (light goes from green to red, no power, engine shuts down). After a few seconds the lockon resets and the trains resume.

I switched to using my old ZW transformer as the power supply, still using command control, and the trains ran smoothly through the switch works.

Any suggestions? I have doublecheck the 180/135 switch on the TMCC lockon, and confirmed the middle and outer rail wires are correct.

Thanks!