I have a serious prob;em, with my Bachmann E-Z Command center. It's about 8 months old. This problem just started> When i turned on my 3 trains. They sit still for about 1-1 1/2 minutes, then they start to run down the track. Then if i try to speed up or slow down the trains, they run at same speed. If I try to stop the trains by turning the knob to off, they don't stop. the only way I can stop them is if I push the emergency button. I cannot seem to get this problem fixed. Any ideas about this problem.  Thank you for any help.

Trainman 11