FTA: The room-size machine weighed around a tonne.

I think “around a tonne” is very light for “room-size”, so I googled, and found https://www.tnmoc.org/news-releases/2019/2/5/colossus-decryp..., which says:

“Standing 2m high, 5 m wide and almost 4 m deep (7 ft by 17 ft by 11 ft), Colossus weighed five tonnes, and used 8 kW of power. Colossus Mark II, which arrived at Bletchley Park in May 1944, had 2,500 valves and 7 km of wiring, and was able to read 5000 characters per second (faster than anything ever produced commercially).”