Block instrument (lock and block)
1897
Clark's block signalling telegraph instrument, 1854
1854
Block instrument (permissive indicating)
Single-needle block instrument
1845
Two-plunger block instrument pattern 288
Block instrument
Intermediate block instrument
Block instrument (sending)
Block instrument (sending/receiving) - Caledonian Railway
Block instrument (sending/receiving)
Block instrument (sending/receiving)
Block instrument (sending/receiving)
Tyer's One-Wire Three Indication Block Instrument
Telegraph Block Instrument; Tyers Patent; 2-position type
Tyers Type Signalling Block Instrument
Telegraph Block Instrument, Great Western Railway
Train describer (receiving) Great Western Railway
BR block instrument
1912
Block instrument with spagnoletti flag indicator (incomplete); GWR. Tyer's style
Block instrument, Great Central Railway (sending)
Telegraph Block Instrument, Signal Relay, Great Western Rail
Three-wire block instrument
Telegraph Block Instrument, Great Western Railway
Telegraph Block Instrument, Great Western Railway Spagnoletti receiving type
Train describer (receiving)
Siemens Bros. block
Telegraph Block Instrument; Fletcher's Type Train Describer
Switch-out block instrument
Telegraph Block Instrument, Great Western Railway
Block instrument (sending)
Telegraph block instrument
Telegraph Block Instrument, Great Western Railway
Telegraph Block Instrument, Great Western Railway
Telegraph block instrument
Single-needle telegraph block instrument
Telegraph block instrument
Telegraph Block Instrument, Spagnoletti type
Wooden shelf with black-painted metal brackets
Telegraph Block Instrument; Fletcher's Type Train Describer
Telegraph block instrument, block bell, ground frame type
Train describer (sending)
Ringing Key for Tyers Block Instrument
Lock & Block Type Telegraph Block Instrument
Telegraph block instrument, London Brighton & South Coast Railway
Telegraph block instrument
Telegraph block instrument, old form of bell instrument
Telegraph Block Instrument, Lock & Block Type, W R Sykes & Co
Telegraph Block Instrument, Markham North
Telegraph Block Instrument, Lock & Block Type, W R Sykes & Co
