GRJ -- at the risk of hijacking this thread - about two years ago I posted a question about 'real' steam engine headlights, here:
steam engine headlights
and, as one might expect, got lots of answers - not all consistent (my question was whether the headlight was off when running in reverse...). At least one opinion held that since the headlight and rear tender light were controlled by a single double throw toggle switch (center off) that one could not have both on at the same time. The context of my question was whether to use directional lighting on a steam engine - i.e. LED(s) wired up to the DC motor leads - or to a dedicated output from an ERR or other board or to go with AC track power, in which case the front headlight would remain on regardless of direction...