Is this a locomotive you have owned and used before, or something that you recently picked up. The reason I ask is because my son and I had this trouble a couple different times. We would put a set on the track in program mode, turn the command base on first and then the power. The tender would start up immediately. We could not get the locomotive to program and respond to the TMCC cab 1 set. I had to first program the locomotive with my 990 Legacy cab 2 controller, then do a factory reset. After the locomotive was programmed, and factory reset using the Legacy controller. Then we could program it to the TMCC cab 1 controller. It seems that sometimes some locomotive's that were originally programmed with a 990 Legacy set, do not want to respond to the TMCC cab 1. Unless the locomotive was first factory reset using the 990 first.