Bill,
To try to correct, I have deleted and reentered both engines in the handheld, but the problem still continues.
It sounds as if one (or both) engines aren't holding their DCS ID#'s. If these are PS2 engines, charge their batteries. If these are PS3 units, the problem (if it is what I'm suggesting) could be more serious. Do as John suggest regarding changing one DCS address.
on the BB1 the trailing unit, when direction is changed the cab light turns on, but the head light does not. Lights work normally on the lead unit. Can this trailing unit bulb be replaced?
Is it a PS3 engine? If so, it's an LED, not a bulb. Regardless, if one headlight doesn't work, it could be due to a board problem vs. a bulb/LED problem.
On the Western Maryland steamer, the headlight is so bright it bothers my eyes to look directly at it. Can this lamp be replaced with a more conventional bulb and less intense glare.
Before you start up the engine, does the headlight come on and get brighter as power is increased? If it odes, the FET on the PS2/PS3 board has blown and is letting track power straight through to the headlight. In this case, do not operate the engine until you replace/repair the board. Otherwise, you'll burn out the bulb/LED, as well.
Were these engines purchased new or used?
