Something wrong with the Engine? DCS signal is wonky..

Not good, The first thing I would check out (without taking anything apart) is the center rail rollers, Are both set working?? Here's an easy test if you don't have a continuity meter.. Place a 3 inch piece of electrical tape on the center rail, Park the engine with one set of  rollers on top of the tape. The other set of roller should fire up the engine. Repeat with other set of rollers.

Sometimes the on the trucks where the red led to the 3rd rail pick up and the black common screws become loose. This also effect the recharging of the battery.

Clean the wheels and pickups thoroughly, Tighten pickup screws.  Check continuity between rollers as mention.

Take off shell and tighten screws for black and red pickup wires.  If you have a continuity issue between rollers need to check for a broken wire at the terminal where it screws into truck, also check wire nut that all reds and all blacks are fully connected respectively under the wire nut.   G