With your normal DCS setup, what happens when you follow the instructions in the Instruction Manual, "* DCS operation is only possible on DCS Variable Tracks. There are 2 ways to activate the caboose in DCS mode. 1. The first is using the TIU Variable Channel, make sure the DCS signal is turned ON, reduce the voltage to 21 volts and then press and hold the bell button down for 3-5 seconds to activate the caboose signal man." Refer to your DCS operating manual for instruction.
Your 18 volts to track will work.
