A Signal BoxThe building in which the Signaller(s) is/are situated together with the control and indication system for the signalling. See also Signalling Centre. at one end of a Block SectionThe section of line between one Section Signal and the next Home Signal. This term does not apply on a Track Circuit Block line. in Block SignallingA system of controlling rail traffic defined by Block Sections. Normally only one train is permitted in a Block Section..