There have been several posts about the crush at Euston Station in London as everybody goes for a train when it is posted shortly before departure.
That appears to be on the way out.
Now the two main companies there, in conjunction with Network Rail who run the station, have agreed that many of Avanti West Coast trains (about 40% to start, rising to 55%) will advertise the platform and allow boarding 20 minutes ahead; London Northwestern are allowing "Continuous Boarding", where passengers can go down to the platform to wait for the arrival of their train as soon as the previous one on that platform has left.
There is a good article, with input from the various parties, in a trade magazine to which I subscribe. The article is at https://railuk.com/travel/the-euston-rush-on-its-way-out-as-early-train-boarding-introduced/