Very cool. Much envy. About the only thing missing is 16 2/3 Hz as present on some (Germany, Austria, Schweiz, Sweden, Norway) European railway catenaries. This "one third of 50Hz" single-phase supply was especially designed for large low-RPM electrical motors in locomotives. There are power stations in Sweden making it from scratch (Porjus hydroelectric power station is probably the most well known, built to supply the iron ore railway from Luleå via Kiruna to Narvik), and then there of course was single-phase high voltage transmission:
![Image](https://privat.bahnhof.se/wb658981/bilder/Elektrifiering/130jv.jpg)
But there also was a widespread network of converter stations where 50Hz was remade into catenary mains using rotary converters. The converters used to be mounted on railway cars parked in mountain tunnels where they would tie in to the grid.
![Image](https://jernbane.net/upload2/n20003605-20000308-1024.jpg)
The tunnels were close to railway lines, so the active equipment could be moved:
![Image](https://www.ekeving.se/r/MATN/OMF/Ebr_41842.jpg)
This was made to protect them in case of war. The location of the tunnels was kept secret and they were surrounded by much myths. Now they are all replaced by semiconductor power converter stations that aren't protected like these. The tunnels now are objects for urbex:
![Image](https://www.antus.nu/bilder/bunker10/ul.jpg)