How did steam loco headlights work?

Pyle-National Dynamotor. A small steam driven turbo-generator that produced 32V DC, usually mounted up on top of the boiler someplace.

Here is a good link with a nice explanation.

http://www.steamlocomotive.com/appliances/dynamo.php

Thanks guys!  Obviously I was completely "in the dark" about this subject!

I am going to go home and see if I can find this dyanamo modeled on my premier Allegheny.

Which manufacturer will be first with a steam (smoke) emitting generator

It was a very fair question. Plenty of train fans never stop and wonder how steam pressure translates to the electric lights.

Some steam engines had 1 or more of these...

NKP 765 used to carry THREE of these!

Now we only need two.

The Southern Pacific GS-4 & GS-5 class Daylights carried three different turbo-generators, and 4449 still has and uses all three:

1) One for 32V cab lights, class lights, train number indicator board, and headlight.

2) One for 12V oscillating Mars Light.

3) One for the original electro-pneumatic train braking system, now used to power the lights under the skirting. 

Also, these are often quite loud. There was a recent question about the "science fiction-y" steam locomotive startup sound elsewhere on this forum. It's the dynamo. When steam is first applied, they make a crazy ascending whistling sound, then settle down to a sustaining whiny-rasp.

Yes, Martin, that is the turbo-generator.

They're not too loud if they are properly maintained. If the commutator is worn and rough, they can make a bit of a racket.

Yes.

C&O Alleghenies set up for dual service like #1650, carried two gennies; the second between the sandboxes, and off set to the right.

Why did they need a second turbo-generator, i.e. what did passenger service have to do with needing a second one?

+1

This is a really interesting topic - one that I never really stopped to even consider.  Glad the question was asked!

-Dustin

I can just imagine the railfans back then, "It isn't the same without the Kerosone Lights, that is a real authentic railroad light" "Kerosene? Hasn't been real since they stopped using Whale Oil!"

Of course, there were other manufacturers of turbo-generators. GE comes to mind.

Actually, electric headlights weren't very popular when they came out. "They produce a very brilliant and powerful light, yet most roadmen oppose their use, claiming they are very injurious to the eyesight."

--Chas. McShane, The Locomotive Up To Date, 1900.

No. the original Dynamotor would have powered the headlight, class lights, and cab/gauge lights, Mars Light, and back-up light on the rear of the tender. The second may have been for the radio, and a third could have been for the in-cab portion of the EOT device system.

On some of O.Winston Link's recording behind the J's, you can hear the dynamo as the engine passes through a tunnel.

Here's a Pyle National mounted on a museum wall to light the building.

If you browse steam locomotive photos online, you will sometimes see them tucked between the stack and boiler-top headlight, just in front of the cab, or almost anywhere else in between.

Not sure why the "dual service " Alleghenies had two, but it's certainly obvious they did. Time to tap into the Huddleston / Dixon resources for those who might want to know the nuts and bolts.  Just a quick thought...did any of the late '40s C&O passenger car orders come with E/P brakes?

Were the same generators used for early electric arc headlights, or did they require a much higher voltage generator?

Yes.

There were some arrangements like a high beam/low beam where the arc light was cut out and an incandescent bulb was cut in, and the engineers wouldn't blind each other. Around the late 1800s there were even some lawmakers trying to ban the nasty bright lights as a danger.