Okay, so I'm not the only one out here with the same problem. After months of trying to figure out what was wrong with my controller I sent it back to the Bachmann reapir shop. My controller was doing the same thing as yours except at times my locos would just start and go in one speed (FAST). I am currently using the EZ Track System by Bachmann. I will soon learn what is wrong with my controller and will share as soon as I find out.  Hopefully someone else has figured this one out. 

Thanks Rich. I will have to do some reseach before I attempt, but I think you have sent me in the right direction. Thanks again.

Can anyone tell me what decoder I should use to add sound to Bachmann Ma & PA #6 W/Steel Cab - Richmond Modern 4-4-0 - DCC.
Thanks
MelR

I'm fairly new to the hobby and after playing with analog Thomas the Train locos with my young son, we have moved on to DCC. I purchased an EZ Command DCC Controller a few months ago and all was working fine. We are using the Bachmann -Your First Railroad Track Pack. Then a few weeks ago we noticed that both the loco (Bachmann ATSF 2121) and Diesel ( Bachmann B&O Chessie System 3139) only run at one speed (full speed). In addition, I have noticed that when I do not insert the power cord from the wall unit all the way into the controller, it sometimes works as intended.

Can someone please direct me to what we are doing wrong or is it a fault of the controller?

Thank you for you help!!!