signal box

noun2

1. •
   A building, typically adjacent to or spanning a railway line, from where signals, points and (sometimes) level crossings are controlled.

   • This includes plans to run earlier [Sunday] services on the Derby to Crewe and Skegness routes, which will require Network Rail to open signal boxes on these lines earlier than at present. — 2019
2. •
   The alarm-box of a police or fire alarm system.