In a couple of threads here, and in the recently published RAIB class investigation, route cards are mentioned as a method of working used during times of disruption or degraded working that (help?) prevent errors by signallers. However, I've not been able to find a basic introduction to what they are, how they are used or how they prevent errors (my Google searches are overwhelmed by hits relating to fell walking and train drivers' route knowledge). Please could one of the knowledgeable signallers here fill that gap?
The essential things in life are seen not with the eyes, but with the heart. --Antoine de St. Exupery
Briefly, on Network Rail lines (including those lines where TfL operates the trains) Route Cards are issued to signalling staff for use when necessary to operate and pass trains in degraded mode. Prior to authorising any unsignalled movement, or authorising a driver to pass a signal held at Danger, the signaller must first check by means of the Card that all points that are required to be in either Normal or Reverse position as appropriate for the movement(and conversely that any such points that would normally be set to protect the proposed movement)are so set and detected and that reminder appliances are applied to the controls to prevent unintentional operation. Signalling staff must also satisfy themselves that any track circuits that may be shewing occupied within the required route when thought to be clear are in fact clear of vehicles by means of visual inspection by ground based staff, who may in any case be on site to operate any points manually. I don't know whether any similar protocols are used on the London UndergrounD though.