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Stations, Junctions, etc
Engine Sheds
Other
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Miscellaneous: Operating Equipment & Practices
Signalling Procedure: misc_equip249
Another extract from the Great Western Railway
Regulations for Train Signalling on Double and Single Lines detailing the
operation of the Tyers No 9 Single Line Electric Token Block System and
photographs showing both sides of the single line Key Token for the North Curve
between Bearley East Junction and Bearley North Junction. The Tyers No 9
Key Token instrument was invented and patented by GWR Signalling Engineers
Alfred Blackall and Charles Jacobs in 1912 and manufactured under licence by
Tyer. It became the standard GWR single line instrument being; more compact,
easier to use and with less moving parts, easier to service and repair than
previous instruments. These instruments were also used on the single line
between Bearley East Junction and Hatton West Junction until that line was
doubled in 1939. For a photograph of the Tyers No 9 Key Token Instruments
at Bearley East Junction Signal Box see 'gwrbj807'.
The Key Tokens were approximately 7¾ inches long and
were initially manufactured from steel and later aluminium alloy. There were
four possible key configurations depending on the position of the semi-circular
groove cut in the key at the end of the token. The one depicted here is a
configuration D. Some key tokens also had an Annett key for unlocking ground
frames at the other end. When in use the Key Tokens were attached to a hoop to
make their transfer easier, see 'gwrbj776',
'gwrbj786' and 'gwrhj1933'.
Robert Ferris
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