The Intercity 250 program was an unsuccessful project by British Rail to have a new fleet of push-pull trains on West Coast Main Line Intercity services. Found a link that may help you out. https://blog.railwaymuseum.org.uk/the-locomotive-that-doesnt-exist/
In the shortest way possible it was supposedly meant to improve express passenger travel on the East and West coast mainlines starting with the West as on the ECML we had the 225s new at the time. It didn't go past the concept stages however as privatisation happened.
