My brother works on locomotives for BNSF in Illinois. He just said either a 32 or74 volt, 200 watt. He didn't remember the actual bulb number (or make). He also said it should be on some data base somewhere on the internet. He goes back to work in a few days, he will look it up.
Well 130amp alternator x 14 volts = 1,820 watts minus low beams of 55 x 2 and minus high beams of 65 x 2 = 1,580 and not sure what it takes to run the vehicle, main power consumers for running would be just the fuel pump and the a/c blower (condenser fan is belt driven).
I'd never want to exceed 1000 watts and I'm sure it does not take more than 580 to run the vehicle.
But anyway, I'm thinking of just going with 4 130W H3 lights.
The nose light isn't the most powerful light on an engine, it is instead the "Mars light" spotlight, which I've seen in action but have since been unable to get anymore information on. Not that it matters to we flashaholics, since we have both [previously] HIDs and [currently] LED throwers..
Again, according to my brother who works on locomotives for a living (and apparently is ranked somewhere around #3 in the US in regards to model railroading, but I digress....) he says the MARS light is merely another headlight set up to 'rotate" (or oscillate) in a figure-eight pattern. Same bulb as the main headlight.