Commuters face another six months of rail delays despite £8billion-worth of engineering on the West Coast Main Line, according to experts at Virgin Trains.

CEO Tony Collins cast doubt on Network Rail’s claims the railway will be functional by mid-December.

When asked if he thought rail users would have a better service in the near future, Mr Collins said ‘the jury is still out’. “We are working with Network Rail to make sure the track is reliable,” he said. “There is a lot of activity going on around the tracks but I still think the next six months will be challenging.

“I think we will still see Network Rail taking a high level of possession of the track for works between now and June and we are anxious to know if the railway will be reliable. As far as I’m concerned the jury is still out on whether or not they’ll be able to deliver.”

Virgin Trains aim to run three trains an hour from New Street to London Euston instead of the current two.

But Mr Collins is concerned an increased service without a reliable railway will spell disaster for commuters.

Travellers have endured delays every weekend and on weekdays throughout the year as part of Network Rail’s programme to replace 1,695 miles of track.

A new rail timetable which will allow a third more trains is due on Sunday December 14.

But with the railway set to close a week later at Christmas for works at Milton Keynes Mr Collins remains sceptical about Network Rail’s efforts.

He said: “This will be a challenge for them. The entire network is going to step up on December 14 and that means more trains running from a number of different operators. I am concerned about whether it will be reliable and I wonder if December 14 is just a little bit too soon.”

Network Rail are under mounting pressure as the company were fined £14million after engineering works at Rugby overran at New Year.

But a spokesman remained confident about their successes and said: “After the problems last new year we have improved processes and since then all major work on the West Coast, some 13 key milestones, has been delivered on time. This is a phenomenal achievement on such a complex project.

“Starting in December, commuters and long distance passengers on the West Coast will start to enjoy the benefits of our work with hundreds more trains and thousands of extra seats.

“To help the new timetable bed in we have agreed with the operator to phase it in over the first few weeks, but from day one 95 per cent of services will run.

“Seven train operators and four freight operators use West Coast – all will see benefits.”