Week 11: Close-up of the internals of the electro-mechanical interlocker at the Santa Clara Interlocking Tower. It uses a system of sliding bars to restrict the rail yard's switch and signal positions to certain permitted combinations. Mechanical business logic, go figure!

Week 11: Close-up of the internals of the electro-mechanical interlocker at the Santa Clara Interlocking Tower. It uses a system of sliding bars to restrict the rail yard's switch and signal positions to certain permitted combinations. Mechanical business logic, go figure!