GWR broad gauge caution board signal designed by I K Brunel. Although these were part of the GWR's original time-interval system of working, this signal has been set to work in the same way as later block semaphore signals so as to function in Trainz. Caution boards were used in conjunction with disk-and-crossbar signals. They would be turned to caution for only a short time after a train had passed and then back to proceed about 5 minutes before the disk-and-crossbar was itself set to proceed. In a later time where these signals still survived they were connected into signal box lever frames and no longer required a railway policeman (bobby) to manually operate them.
Thanks to KlausM for permission to use his scripts and his assistance, also to Jerker, PhilC and Bob Vipond for their help; also Bob the beta tester. This model is in memory of Ricky Sykes 1943-2008.