I dont have very complex lighting of locos. I dont have any locos with ditch lights, mars lights, etc. I don`t have lighting triggers or sensors, for complex Rule 17 or otherwise.
So is it acceptable for my locos to have lights on in both forward and reverse, with dimming. Or to be realistic, should I differentiate between switchers, road switchers, and big locos re lighting.
This is going to be very generalized post about engine controls in reference to their lighting.
The control stand for the engineer generally will have three switches. Front lighting, rear lighting, and ditch lights. The headlight switches have thre positions; Off, Dim, Bright. This goes for front and rear. There’s nothing stopping an engineer (other then certain rules) from having both sets of headlights on full blast. The ditchlights are slightly different, usually only having selection between Off, Rear, Front.
And were you referencing classification lights? Many locomotives have had the classification lamp housings filled in with round sheet metal and the lights removed. In modern day, you may see an SD-40 doing yard work while a GP-38 goes on a road job while a smaller SW1200 does some local switching for a few towns. Classification lights are just an extra (and unneeded) expense for railroads now.
Most model engines (at least in HO) now come with reversing headlights - the headlight is only on in the direction of travel. That was/is virtually non-existant in the prototype, much more likely to see both headlights on.
In DCC I prefer to set my headlights up so the one in direction of travel is bright, the other one dimmed but still on.