![The signalman waits to exchange the single line token at Williton station on the West Somerset Railway, England, UK Stock Photo - Alamy The signalman waits to exchange the single line token at Williton station on the West Somerset Railway, England, UK Stock Photo - Alamy](https://c8.alamy.com/comp/G17KYJ/the-signalman-waits-to-exchange-the-single-line-token-at-williton-G17KYJ.jpg)
The signalman waits to exchange the single line token at Williton station on the West Somerset Railway, England, UK Stock Photo - Alamy
![The LMS Society - Single Line Working &Amp; Tablet Exchange Apparatus. Part 1, Methods of Single Line Working The LMS Society - Single Line Working &Amp; Tablet Exchange Apparatus. Part 1, Methods of Single Line Working](https://lmssociety.co.uk/assets/protophotos/TabletExchangeApparatus_1_1.jpg)
The LMS Society - Single Line Working &Amp; Tablet Exchange Apparatus. Part 1, Methods of Single Line Working
![The signalman exchanges a single line token with the fireman of steam train at Williton station on the West Somerset Railway, En Stock Photo - Alamy The signalman exchanges a single line token with the fireman of steam train at Williton station on the West Somerset Railway, En Stock Photo - Alamy](https://c8.alamy.com/comp/F6XH9R/the-signalman-exchanges-a-single-line-token-with-the-fireman-of-steam-F6XH9R.jpg)
The signalman exchanges a single line token with the fireman of steam train at Williton station on the West Somerset Railway, En Stock Photo - Alamy
![Signalling Procedure: An extract from the 'Great Western Railway Regulations for Train Signalling on Double and Single Lines' Signalling Procedure: An extract from the 'Great Western Railway Regulations for Train Signalling on Double and Single Lines'](https://www.warwickshirerailways.com/misc/miscellaneous/misc_equip249.jpg)