VIRGIN Trains' £600m fleet of tilting Pendolino trains will this week finally do what they were intended to do - tilt.

Two services each way between Liverpool and London will tilt on "appropriate' sections of the West Coast line, allowing train speeds to increase from 110mph to 125mph.

It is effectively a chance for the operator to test the tilt before a fully revised timetable - featuring tilting trains - comes into operation on the upgraded West Coast line on September 27.

The 0703 and 1503 from London to Liverpool and the 1035 and 1835 from Liverpool to London are affected.

Track improvements and increased train speeds will reduce the journey time between Liverpool and London from almost three hours to around 2 1/2 hours from September.

The tests will not improve the current timetable, but may allow late services to make up time.

David Ewart, spokesman for Virgin Trains, said: "We will be tilting the Pendolinos on appropriate sections of the line near Rugby where 125mph running has been authorised.

"This is to build up service experience. We've now got many drivers fully trained up, the trains tilting and the line upgraded in many parts.

"We're confident that on September 27 all the necessary line upgrades south of Crewe will be complete and we can introduce the new timetable."

Virgin's 53-strong fleet of Pendolinos are actually designed to operate at 140mph but the controversial West Coast line upgrade, now expected to cost £8bn, will only actually allow 125mph running.

That will only be south of Crewe, as the line between Crewe and Liverpool will still not be in good enough to take 125mph trains.