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Osram 100V 32.5W London Transport Signal Lamp Thanks to Lucas for this trade, here is a signal lamp as used on the London Underground. It is a 100V dual-filament lamp rated at 32.5W (both filaments lit together). The cap is a 3-pin BC (B22d-3) cap and is attached to the lamp in such a way that the filaments are correctly aligned with the optical system of the signal when the lamp is in place. When one filament fails, the circuit sends a signal to the signal box and/or signalling engineers that the lamp needs to be replaced. Meanwhile, the remaining filament continues to operate at reduced intensity. I believe that these lamps may still be in production, as there are a great many incandescent signals still in use on the system, perhaps someone can confirm..? Keywords: Lamps

Osram 100V 32.5W London Transport Signal Lamp


Thanks to Lucas for this trade, here is a signal lamp as used on the London Underground. It is a 100V dual-filament lamp rated at 32.5W (both filaments lit together). The cap is a 3-pin BC (B22d-3) cap and is attached to the lamp in such a way that the filaments are correctly aligned with the optical system of the signal when the lamp is in place. When one filament fails, the circuit sends a signal to the signal box and/or signalling engineers that the lamp needs to be replaced. Meanwhile, the remaining filament continues to operate at reduced intensity.

I believe that these lamps may still be in production, as there are a great many incandescent signals still in use on the system, perhaps someone can confirm..?
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Lamp/Fixture Information
Manufacturer:Osram
Model Reference:LT Signal
Lamp
Lamp Type:Incandescent, dual filament
Filament/Radiator Type:2 x Tungsten filaments
Base:B22d-3 (#-pin BC)
Shape/Finish:A60, clear
Fixture
Fixture Type:Railway signal
Electrical
Wattage:32.5
Voltage:100
Optical
Colour Temperature:2800K
Physical/Production
Factory Location:England (location unknown but believed to be Wembley)
Fabrication Date:May 1991 (Date code YE)
Application/Use:Signalling on London Underground Railways
File information
Filename:LT_100V_32_5W_Signal_Lamp.jpg
Album name:Ria / Incandescent Lamps
Keywords:Lamps
Filesize:402 KiB
Date added:Sep 01, 2024
Dimensions:2072 x 1288 pixels
Displayed:13 times
Software:Shotwell 0.31.3
URL:https://trad-lighting.net/gallery/displayimage.php?pid=433
Favorites:Add to Favorites

Comment 1 to 4 of 4
Page: 1

Max   [Sep 01, 2024 at 10:15 AM]
What an odd lamp. 32.5 W is very specific though... they could not round it to 30, 32, 33, or 35 W?
Ria   [Sep 01, 2024 at 12:35 PM]
I have absolutely no idea why it is such strange rating, there must have been some reasoning behind it, but I'm as baffled as you are..! Wonder
wide-lite 1000   [Sep 03, 2024 at 02:17 AM]
Maybe it was to provide a specific lumen output .
Ria   [Sep 03, 2024 at 06:59 AM]
Could be, although I wouldn't have thought that was so specific a requirement. But then I'm not a signalling engineer.

Comment 1 to 4 of 4
Page: 1