Class J/K class lights

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In response to Mr. Goodman's question:

32v was standard voltage in steam days. There was nothing run by electricity save the lighting. The first electric headlights were carbon arc lamps, which required a "steam dynamo" to power them. The carbon arcs were quite problematic and were soon replaced by incandescent lamps, and since the engines already had 32v "dynamos," 32 volt lamps were used.

32v continued to be the lighting and (I think) control voltage into the Diesel era. There was at least one major railroad which was still ordering 32v locomotives into the late 1980s or early 1990s. I believe the standard lighting and control voltage on engines today is 64v, but this is about 150 years out of my era of interest and I just don't keep up with "modern" information.

Yes, I, too, was surprised to see a little plastic Simpson voltmeter used on a steam engine. That the little thing stands up to the shaking and the pounding is a testimony to the ruggedness of the tiny d'Arsonval meter movements. One would think the pinning of the hairspring would have been shaken loose long ago. (I have some d'Arsonval millammeters from the 1930s in use on my telegraph circuits, and they have probably been through trillions of operations over the years, and are still going strong.)

BTW - The overhead pivoted lighting switches used on headlight circuits and shown in Mr. Chad Jordan's photos from the cab of the 611, were standard headlight switches and were still available from Pyle National a few years ago. Even the early Diesels had them.  The shells are cast aluminum and they are furnished either with or without a large ceramic dropping resistor for the display of the "dim" headlight. If anyone needs interior photos, I think there are two of them around here somewhere which could be found and photographed with a little effort.

        -- abram burnett
Capacitively Coupled Telluric Turnips