this post was submitted on 06 Jan 2026
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This is the first central control room of the Stockholm Metro, it controlled what is now known as the green line.

Before this central facility, there were two control rooms as the Stockholm Metro had started as two separate systems which were later connected.

For those who want to learn more about the history of communications (with a focus on radio) used in public transport in Stockholm, I recommend this (Swedish) website, it is very informative:

https://fordonsradio.se/

As for the photo I linked, it is licensed CC-BY-NC, sadly the original photographer is unknown at this time.

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[–] awaysaway@sh.itjust.works 5 points 4 days ago (2 children)

do you know what exactly is happening / represented on that board?

i'm day dreaming that it is a realtime mechanical reflection of the transit system.

[–] stoy@lemmy.zip 8 points 4 days ago

I don't have any complete knowledge, but I can tell you about how similar systems from the same era worked.

Let's start from the beginning.

The track is divided into electrically isolated sections and have track circuits going to them, this circuit is built so that each rail is connected to one either side of the circuit, meaning it is only completed if something metal bridges the rails, like a train wheel/axle combo.

So you now have a system that detects which track sections are occupied, that is sent to the control central and lights up the track section to show that it is occupied, it is also sent to the signal system, which sets the closest signals for trains approaching the section to stop, which in turn sets the relevant pre signals to caution.

In the boards like this that I have seen, all signals on the track have their currently set signal also displayed on the board.

They also usually show the current status of track switches.

There are usually some manual override controls for the control center to be able to over ride signals and switches manually should the need arise.

[–] calliope@retrolemmy.com 6 points 4 days ago* (last edited 4 days ago)

I was curious, so I translated parts of the website (it’s under the Icarus Tunnelcentralen section) using whatever is built into my browser right now.

The control board did not indicate or operate any train positions, it was reserved for the respective switchgear in Johanneshov and Alvik.

If you zoom in on some of the additional images you can see that it did seem to rotate the bits to indicate switch positions, but I could be wrong!

Incredible system, very cool photos!