I do enjoy reading your responses and I'm really grateful for your continued interest.
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PS. I meant to ask, would it help if I were to measure the output of the EZ controller to see if it jumps causing the sudden start? I do have a digital meter.
Well Sarah, if there's one thing that most of us on here seem to like, it's trying to help! If we can give advice then we will......
I don't think that you'll get any useful result trying to measure the output of your EZ Command - the point about all DCC systems is that they supply a constant voltage of very fast-cycle AC to the track, with the command signals to the loco decoders being superimposed onto this AC voltage (don't worry about how this happens, just accept that it is all Arcane Magicks that happen inside the controller box, and most of us don't really understand it either...); so if you connect your meter across the output all you will see (if anything) is the constant voltage. What happens when you turn the controller knob is that it sends coded signals to the loco decoder, which tells the decoder how much voltage to actually feed into the motor.
I hope that makes some kind of sense? I really can't answer the question about the sudden starting and stopping, except to think it is something to do with the way the loco decoder is set up...?
Jon.