The Colossus Rebuild Project by Tony Sale

Colossus Reborn

The front racks of Colossus

This shows the view along Colossus from the J Rack, past the K Rack with its large switch panel, past the Relay Rack to the C Rack, the Counter Rack.

The signals from the Logic panel at the top of the J Rack are at present wired directly to the Counter Control Panel on the Counter rack. Eventually when I have access to Colossus, the signals will be switched on the K Rack switch panel which is now wired up but not connected. You can see how this switching will work (as it did in WW II) by accessing the Virtual Colossus simulation on

This page was originally created by the late Tony Sale, the original curator of the Bletchley Park Museum, and Secretary of the Bletchley Park Heritage Society.