The 1659 London Bridge to Horsham left virtually on time yesterday, but ground to a halt at the 'advance starters'. We sat there for a few minutes with the conductor telling us we were waiting for a red signal to clear (thanks!), then crawled a few metres forward and stopped again. This was repeated once more, and then, after another few minutes, the driver sounded a long blast on the horn and crawled forward again (past the signal), after which we stopped very suddenly again. After a further couple of minutes we set off as normal. The delay meant I missed my hourly train to Betchworth from Redhill which the staff there sent off despite seeing us dashing along the platform to catch it.
Was this an instance of the driver stopping too short of the signal, and, if so, why is this an issue at these spots?