This is the original forum of the Bristol Railway Archive that existed between 2003 and 2013. I finally rescued it after it seemed unrecoverable after a large crash. I have made it available for viewing. It is locked, all posts to the new version please!
Twas a bobbing track circuit failure. When trains are authorised past signals at danger the driver is instructed to proceed with cauntion and be prepared to stop short of any obstruction. Thus the drivers should be going a lot slower than usual, about 20mph I guess.