Steam Locomotive Headlight Bulbs, Resistors, and Electrical

Pegasuspinto · **Joined:** Fri Mar 26, 2010 11:43 am **Posts:** 783

The multipower web page doesn't look like it's been touched in 15 years. Looks like an orphan dead end to me.

Maybe it would be simpler, to have someone create LED lamps that would fit, form, function like the incandescent headlamp bulbs they are replacing. Or someone needs to buy the equipment to manufacture lamps and keep making them for the niche applications.

Or we just need to have this stupid ban overturned. There are not many incandescent lamps being used anymore that I can see, is it really needed anymore?

Matthew S · **Joined:** Sun Jun 04, 2017 7:34 pm **Posts:** 8

Mike Tillger wrote:

Bob, Thanks for the heads up on the poor quality of the PDFs. I was unable to edit the original post for some reason. I have posted better quality images below (I hope!).
Resistor info

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ExtractPage2.pdf

Wiring diagram

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Thank you for the updated images!

Matthew S · **Joined:** Sun Jun 04, 2017 7:34 pm **Posts:** 8

Bad Order wrote:

Does that bulb actually have two contacts on the bottom?

I don't think it does. A threaded base isn't conducive to contacts on a bulb aligning with contacts in the socket. It's not feasible. A bayonet mount (like older brake/tail light bulbs).. I could see that, but not threaded E26's.

I suggest that the center post inside the bulb is to steady the filament, since it's a rough service bulb. Don't want that filament to break during use while white hot. Look in the glass envelope the filament leaders are anchored in... you can just about see the two outside leads going down to the base.. .there's nothing beneath the center post.

Surely the headlight switch contains the resistance for dimming.

I'd agree that seems to be the more likely of the two. Trying to find resistors for the dimming, but yes they would go with the switch.

Matthew S · **Joined:** Sun Jun 04, 2017 7:34 pm **Posts:** 8

Tony Pignaloni wrote:

Since the incandescent light bulb ban is taking effect this year, the manufacture if incandescent bulbs has been stopped. You will not find an incandescent bulb except from old stock and collectors. Once factories stop producing incandescent bulbs even Amsco won't be able to have them made. Unless there is some underground operation in some third world country but the quality would be questionable.

I talked with Aamsco today and they said that the bulbs have been discontinued by the manufacturer on account of being unable to source the filaments.

I did not realize there was a bulb ban, but that certainly does not help.

Overmod · **Joined:** Thu May 24, 2012 1:37 pm **Posts:** 2492

What they need to arrange imho is to have the glass 'bulb' envelopes and the compatible bases contract manufactured. You then use a 'cob' style LED element with appropriate heatsinking and driver electronics "in the middle" -- the glass envelope keeping the 'look' of a bulb, and the base remaining a compatible connection.

You could use voltage-to-voltage conversion to get the 'dim' power from the turbogenerator.

Kelly Anderson · **Joined:** Tue Sep 14, 2004 7:52 am **Posts:** 2477

Bad Order · **Joined:** Sun Jun 23, 2013 1:16 pm **Posts:** 231

Overmod wrote:

What they need to arrange imho is to have the glass 'bulb' envelopes and the compatible bases contract manufactured. You then use a 'cob' style LED element with appropriate heatsinking and driver electronics "in the middle" -- the glass envelope keeping the 'look' of a bulb, and the base remaining a compatible connection.

You could use voltage-to-voltage conversion to get the 'dim' power from the turbogenerator.

I've experimented with the bulbs the railroads use for area lighting on locomotives these days... the screw-in replacement for the rough service incandescents... they're LED.. "COB"... "chip on board"

They're nominally 74 volt. I can tell you with all certainty that they will run on AC or DC voltage. They will run on as low as 24 volts and put out full intensity light. I run some off of a regular old doorbell transformer as illumination in a building.. 24 volts AC. There is no doubt they'd run on 32vdc from a turbogenerator. I've played with the bulbs with a "Variac"... variable AC transformer... you get much over 74 volts and the bulbs extinguish themselves.. they don't burn out.. they just go out. Lower the voltage and they come right back on. Get the voltage too low, they go out, too.

There are two types of these LED bulbs in use on locomotives. One is the normal looking bulb, and the other is what they've termed the "Corncob" bulb. I don't have a picture, but google is your friend. The corncob bulbs are used in locomotive number boards and other places where the light needs to shine outwards, not downwards, like under steps and running boards.

The reason you couldn't use the "normal" bulb is because the led's face up from the base.. there would be nothing to reflect. You might be able to get away with using the corncob type bulbs.. the led's face outwards 90° from the base... they'd reflect.
It would be worth the effort to experiment on your locomotive and see if it'd work.

jayrod · **Posted:** Wed Feb 22, 2023 9:46 pm

We discussed this a bit about a year ago. No resolution there either. Do a search for “led bulbs” and you’ll see some threads pop up. Search button is in the upper right at the top of the page.

Dick_Morris · **Posted:** Thu Mar 09, 2023 5:31 am

If a 120 volt bulb could be found that would physically work, there are voltage converters that will convert 32 volts to 120 volts and one could be fitted into the headlight case. There might be a better chance of finding a suitable 120 volt bulb than a suitable 32 volt bulb.

edward · **Joined:** Mon Aug 23, 2004 10:17 pm **Posts:** 23

Dragging up an older thread, does anyone have a source for 34v 250w steam locomotive headlight bulbs? Aamsco/Ferrowat no longer sells any vintage bulbs. Thanks.

Wowak · **Posted:** Sun Jan 05, 2025 9:50 am

edward wrote:

Dragging up an older thread, does anyone have a source for 34v 250w steam locomotive headlight bulbs? Aamsco/Ferrowat no longer sells any vintage bulbs. Thanks.

Not that I'm aware of. I've heard that a few organizations are trying to organize a custom order to be made somewhere overseas, but that's still in the development phase. Maybe somebody involved can expand on it, I'm not a part of it.

Dick_Morris · **Posted:** Mon Jan 06, 2025 6:10 am

See the latest Alaska Railroad #557 status report for the possibility of a (head) light at the end of the tunnel.

https://alaskarails.org/pix/former-loco ... index.html

AndySchwering · **Joined:** Thu Aug 29, 2024 10:31 pm **Posts:** 14

Wowak wrote:

edward wrote:

Dragging up an older thread, does anyone have a source for 34v 250w steam locomotive headlight bulbs? Aamsco/Ferrowat no longer sells any vintage bulbs. Thanks.

Not that I'm aware of. I've heard that a few organizations are trying to organize a custom order to be made somewhere overseas, but that's still in the development phase. Maybe somebody involved can expand on it, I'm not a part of it.

We bought 20 with the part number:

/ NSN:6240-00-299-3386

it is an aviation bulb.

Pegasuspinto · **Joined:** Fri Mar 26, 2010 11:43 am **Posts:** 783

Not an aviation bulb, It appears to just be the military / government number for the railway lamp. Probably all new old stock. The only question is, do they have 12, or 12 thousand, or 12 million, in a warehouse. Get 'em while they are good....

edward · **Joined:** Mon Aug 23, 2004 10:17 pm **Posts:** 23

[quote="Dick_Morris"]See the latest Alaska Railroad #557 status report for the possibility of a (head) light at the end of the tunnel.

https://alaskarails.org/pix/former-loco ... index.html[/quote]

Looks promising! I look forward to learning about the results of your tests. Thanks.