As I understand it, the red line is the Tories answer to creating a crossrail of the north. They said, repeatedly, that they would build 2 extra platforms. Instead they did not. This leaves platforms 13 and 14 as the hell on railway earth they have been for years.
Instead, we have this wonderful red line. It theoretically allows a bit of room for passengers to disembark. Of course it does no such thing because there are two many passengers using this complex, mixed traffic, interchange platform. There have been for years. There is only so much that little piece of tarmac can be asked to do without things getting silly, which they did about a decade ago.
So before the OP gives himself a hernia he might want to vent in the right direction. Our current political masters who say one thing and do another.
The theory of that red line is actually not bad, create room around arriving trains to get people off the platform so that boarding can then take place in a calm way. Of course it doesn’t work, because there are too many passengers for the platform and not enough seats on the trains. Weirdly, staggeringly, what that results in is a massively unpleasant rugby scrum like experience made even worse by futile and usually rude shouts to get behind it and place yourself exactly where?
The bloke in No 10 mate, that is who is responsible for the red line, and you can bet your bottom dollar he will have crossed it plenty of times.