I don't have any MRC products, but it sounds like the two throttles may be set on the same address and interfering with each other. As already suggested, read the instructions that came with both throttles and see if the address of one or both can be changed so they don't conflict.
Is there an error mesage displayed on the throttle? My PE does that if there is a short on the layout but it usually displays a message.
Alternatively, did you assign a cab number to the throttle? IIRC they default to 001 but maybe not. Check your manual for more info on that.
Modeling the Cleveland and Pittsburgh during the PennCentral era starting on the Cleveland lakefront and ending in Mingo junction
I just uninstalled and old MRC DCC system and installed a new 1410 Prodigy wireless. While running in teathered mode I keep losing control of the engines. Once I reset the system I'm ok for a while then I lose them again. The railroad is 15'x25', is divided into 3 separate blocks, their are 4 engines on the track and only one is selected andI am using an MRC 8 amp power supply. Any help would be appreciated, Al