Train-building company Alstom has reached an agreement with the UK Department for Transport (DfT) to construct four new high-speed tilting Pendolino trains for the busy West Coast Main Line (WCML) from London to Glasgow.

The new trains with 11 carriages each will be put into service between 2011 and 2012 according to Alstom.

Two carriages will also be added to 31 of the 52 Pendolinos currently on the route - raising their capacity to 589 passengers – which will be enter service between April and December 2012.

Overall, 7,420 additional seats will be provided, with an option for a further 42 carriages by 2013. Alstom’s contract for the work – due to be confirmed in August - would be worth £1.5bn ($3bn).

Transport Secretary Ruth Kelly said: “Our priority for the railways is increasing capacity and this will provide much-needed extra seats on the busiest services from London to Birmingham, Wolverhampton, Manchester, Liverpool and Glasgow.

"In addition, the £8.8bn [infrastructure] upgrade of the West Coast Main Line will cut journey times and deliver more frequent services."

DfT also announced that Govia Transportation Projects Ltd and Virgin Rail Projects Ltd make up the shortlist to win the contract to deliver these carriages to service – this would include support during the design finalisation, manufacture, delivery, testing and commissioning of new Pendolino rolling stock through to the end of the current West Coast franchise (31 March 2012).

• Network Rail completed infrastructure upgrades to the WCML on time this weekend the company said, after severe overruns on similar work at Christmas and New Year.

“Our planning and preparation for major works is now more robust and the successful delivery of the work this May bank holiday is how it should be,” said Network Rail CEO Iain Coucher.

“Our job was to do [the work] invisibly – to get in, rip up the old railway, put in a new better one – and then get out on time, while causing the least amount of disruption possible.”

There was disruption today (6 May) however, when eight Virgin trains were stopped when signals failed at Bletchley, Buckinghamshire, but the problem was said not to be related to the weekend work.

The trains were eventually able to complete the journey to London, and a Network Rail spokesman told ABTN that engineers were on site but had not managed to fix the problem.

“However we have four trains leaving Euston every hour at the moment – about half capacity – and they will try and get the problem fixed as quickly as possible,” he said.