How surprised can you be when a train passes a platform? Unless you thought it was the bus stop, that is what I was getting at with the 'stupid' comment.
In the incident I related at the start of the thread, I was stood at where carriage 5 of 8 would stop (at the north end of the platform) from which the train approached, behind the person standing adjacent to but still behind the yellow line. Because as previously mentioned, the platform was very crowded I couldn't see very far along the platform to either left or right. I did know a train was approaching, as I have learned which track circuit boundary triggers the relevant approaching announcement on the station Passenger Information System. Because the vast majority of movements stop, this set my normal expectation for the time that would elapse before train's arrival. Having heard that the, "approaching train is not scheduled to stop at this station" and being an interested railway industry worker, I stood on tip-toe and to see what was approaching and, much sooner than even I expected, I could see just the roof of the train approaching at speed.
Given that most of the passengers next to me were probably not interested railway workers, some with headphones on or at least looking at smart phones and given the announcement is fairly low key and did not suggest that the train would pass at speed and given that until the visual message only changed (at the same time as the announcement) from the 08:25 London King's Cross is expected at 08:59 to stand clear very shortly before the train actually passing at 08:57:30, the answer in this case was clearly very surprised in quite a few cases. They were clearly not aware of it until it reached them.
Again my point wasn't specifically about the yellow line. I certainly couldn't see people standing beyond it (although clearly a few do from time to time). It is painted about a metre back from the platform at this location.
The speed of the passing train clearly caused those around me to feel they were in an uncomfortable or unsafe position that they would prefer not to be in. They might have sought to stand in a safer position if the horn had been sounded and / or the station PA was clearer in indicating that the train would pass at speed. It is important to distinguish between inadviseable behaviour of passengers being foolish enough to stand beyond the line, even where such things are a frequent occurrence on the one hand and untypical situations such as this on the other. One of the supervisors at WGC in particular berates anyone doing this with the station PA or simply by shouting! However, in this case many more passengers than even a normal peak loading were on the platform as the expected train was to be the first towards London after a two hour interruption to the peak service.
I do know that the slow lines through Welwyn Garden City are used by freight and ECS workings, but in my experience of these 40 to 50 mph (as was the case for the two following trains) and sounding the horn on approach is normal. Freight and ECS are of course kept away from the busiest times in the busiest direction when the capacity for passenger services is most required. This means that a high proportion of passengers will rarely see such a train pass. Whether we like it or not, our industry's passengers are conditioned by what they normally encounter and the principles of railway safety management require that this is taken account, such that the risk is mitigated to the level of 'as low as reasonably practicable'