Expresses it, I s'pose." The cushion was not aware that M. Studer also refers to continuous-current dynamos only. [20] The Robertson. Chapter X. RAILWAY BRAKES. The Vacuum Automatic brake--The Westinghouse air-brake 187 Chapter XI.--RAILWAY SIGNALLING. The block system--Position of signals--Interlocking the signals--Locking gear--Points--Points and signals in combination--Working the block system--Series of signalling trains from station to.