Runaway locomotives : LUSENET : Wiring for DCC : One Thread

I have a MRC Command 2000. While operating a non-decoder equipped engine, on occasion one or more of my decoder equipped locos will all of a sudden take off at full speed. Help! The locos in question came with the Command 2000.

-- Andy Yodis (, March 06, 2002


I have a similar problem but no answers yet from MRC. I can tell you that DCC communication is being lost to your decoder equipped engines, perhaps through a momentary short, somewhere on your layout. When power is interrupted to MRC decoders, apparently they go into a "full power ON" mode causing the train to run away at full speed until power is cut completely. Other decoders like Digitrax assume a 'Power OFF' mode under the same conditions, preventing runaways. In my case, when communication is disrupted by unplugging and replugging the remote 'Walkaround' throttle, MRC equipped decoder trains will runaway.

Here's my problem in more detail as posted on this site:

Command 2000: I have experienced loco runaways using MRC Command 2000 with MRC PowerStation-8 booster and MRC Walkaround throttle in use. If the Walkaround is unplugged while a train is running, the loco will runaway when the remote throttle is plugged back into the same recepticle. This occurs using the standard Walkaround cable plugged directly into the Command 2000 unit or using an extension wired into my layout. Runaways do not occur if (1) the booster is removed from the circuit or (2) the remote throttle is turned OFF on the Command 2000 and throttles #7, #8, #9, #10 are used. My layout is 75 ft. point-to-point with proper bus and feeder wiring for DCC. All 5 locos have MRC 310 decoders. Even using an 8 ft. test track not connected to the layout, loco speeds will change noticeably whenever the Walkaround throttle is ON (Set 1). Also, locos programmed for Walkaround use will creep very slightly when all throttles are OFF.

All my equipment, including a locomotive, is at MRC after their first tests of my Command 2000 and Walkaround throttle found no problems. Any ideas?

Steve Miller

-- Steve Miller (, March 15, 2002

-- Steve Miller (, March 21, 2002.

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