Trainman, look for this thread on the serial data buffer
R2LC Serial Data Buffer
by Gunrunner; he found this issue on the Cruise M picking up an RS4 by ERR; great solution; simply put sometimes the serial data from the R2LC does not have enough muscle to carry the DCDS and railsounds; Guns has a great solution. Keep in mind I use ERR Cruise Cmdr when there are no Lionel modular boards to improve. Guns is a wizard; have fun and good luck; Falcon70