Network Rail is expected to announce today the series of projects, some of which are already under way, would improve the reliability of the infrastructure and punctuality of train services on the West Coast Main Line, Britain's busiest mixed-use railway.

It includes upgrades to overhead lines and adding new security fencing.

Dyan Crowther, route managing director for Network Rail, said: "This line has seen tremendous growth in traffic and passengers over the last five years and, just like a busy motorway during rush hour, more trains mean that if something goes wrong, the knock- on effects can be significant."

Chris Gibb, chief operating officer at Virgin Trains, said: "We are starting to see investment actually taking place but both Network Rail and the train operators need to keep the pressure on to ensure lasting improvements in performance are achieved."