Signalling

There is currently no formal signalling control on the Bunk Line, with the railway operating "one engine in steam" principles. This means that in normal circumstances, only one train may operate between Wallingford Station limits and the bufferstops at Cholsey. This arrangement is enhanced by use of a token, which is carried by the driver of the lead locomotive of any train leaving station limits. Four ground frames in total control the points at each station, all unlocked by a key on the token.

Various additional or amended rules, in the form of written instructions or "Traffic Special Instructions" allow for some circumstances to override the one engine in steam rule, including for example permissive working at Wallingford Station (two trains using the platform together) or carrying out shunt release at Cholsey, a complex procedure used when the locomotive is too long to run round normally.