alt Hacker News>This big industrial switch toggled between day and night. I don’t know if it changed the operation of the system, or is just switched on some sort of a dark mode for the panel itself:
I think we can answer that with 'yes, it changed the operation of the system. The indicator next to it is labeled in Amperes and 30 Amps is a lot of current. depending on the driving voltage at 24 V (pretty common for control panels like this one) that's 700W give or take and if it is a line voltage (220 V in poland at the time) that 6.6KW.
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You are probably right, but I feel like a gigantic dashboard like that could well use 700W in just its own lighting.
No, these two elements are not related. Day/night switch is for panel backlight. Current meter indicates current drawn by rail switch motors.
I know a few things about German signal boxes, and I doubt the Polish ones will be too different in this regard.
Railway signals have a “daytime” and a lower “nighttime” intensity to make sure that the driver sees the red signal in the summer sun, but doesn’t get blinded by the same red signal on their final run of the day at midnight. The switching between these intensities is done on the signaling panel and I assume that’s what the big switch is for.