This debate about benefit vs accident risk is much wider than foot crossings on the railway (and indeed I would argue that Network Rail is taking a very narrow view of it, hence my use of the word 'perfectionist', and perfection is generally unachievable, so NR are limiting the use of the railway because it can't be perfect). We are concerned, naturally, about the number of 'Elsenhams'. Let's just broaden this a little. What about the risk to pedestrians of trams on city streets? This exists and is calculable, and indeed there has been the occasional pedestrian death on city streets ever since the first modern city tram, Manchester Metrolink, was introduced. If it is right to be perfectionist about this, then none of the city trams should have been allowed. but they were, and are generally a success. The trams demonstrate that it is right to take measured risks in the pursuit of an overall gain to the public.It's not just industry regulation but legal responsibilities as well. People who could be put on trial for offences such as manslaughter tend to be very cautious before signing off on something with known risks.
Incidentally, a friend of mine worked for GEC-Alstom on the development of the original control systems for Metrolink. He left when he realised that, statistically, there was bound to be the occasional death caused by someone being hit by a tram, and he feared that he or his colleagues would be held responsible and/or prosecuted. The occasional death did, sadly, happen, as predicted. There were no prosecutions. It was a foreseen risk and it was being managed. Judgement and calculation and common sense are called for. Not perfectionism.