I have the same problem on my Class 221. This part is called "drive cup". The two on my power car was broken. I got a new pair directly with whom sold me.

Super Voyager is a tilting train with aprox. 31cm of lenght each car, and if not suitable for sharp curves. I think the problem occurred by forcing the train in curves with tight radius. When the train tilt, body contacts the wheel and holds the engine. As the parts are plastic, forcing the controller, can damage the transmission.

More experiences. I started to leave power supply on for longer periods of time and the problem was gone for a while. 
I noticed that power supply don't heat to stay long time on.

Quote from: Kris Everett on December 27, 2010, 07:02:36 AM
you should let it rest about 30secs to a min before you power up again this should give it enough time to reset its self hope you get it working

I tried this but failed. I think my system is having problems. Sometimes it works perfectly. Sometimes the left LED is blinking and nothing works.

See the diagram of your locomotives to correct procedure to remove body. I added sound in my FT-A.

Today the problem returned. I moved the command station to another place to see if it was light and didn't work.
Only after you turn off and on several times that the system returned to work normally.  But I'm afraid to damage the system with this procedure.

I'm having this same problem. I tried to turn only the command station without any other connection noticed the problem. It have something wrong with power supply?