ANGER erupted last night as plans to run an extra two trains an hour on Scotland's busiest commuter route were axed after the Scottish Government cut £350 million from its rail investment programme.

Business leaders and Labour politicians were incensed as the flagship Edinburgh Glasgow Improvement Programme (EGIP) saw its budget cut from £1 billion to £650m.

It means the current timetable of four trains an hour will be maintained, instead of the proposed six services an hour between the country's two biggest cities. Journey times for the fastest services will be reduced by eight minutes, rather than the 13 minutes planned for.

Other changes will see only half the electrification of central Scotland's rail network originally intended – with Stirling, Dunblane and Alloa no longer benefiting from faster electric trains.

Liz Cameron, chief executive of the Scottish Chambers of Commerce, said EGIP's reputation as the "jewel in the crown" would not be delivered. She added: "The new plans that have been announced fail to achieve the improvements in journey times that have been promised, fail to guarantee the pledged electrification of the network to Stirling and Dunblane and fail to deliver the six trains per hour between Glasgow and Edinburgh that business travellers have been demanding."

Labour's transport spokeswoman Elaine Murray said it was a step back. She added: "While we welcome any progress on bringing our rail service up to scratch, it is disappointing the SNP Government has rolled back on many of its earlier promises. The original plan was to increase the frequency on the Glasgow-Edinburgh line from four trains to six and bring the journey times down even further, while passengers who use the services to Stirling and Dunblane will be disappointed this will not be electrified."

The EGIP project will still deliver a boost in seats on the busy Glasgow-Edinburgh corridor – with the introduction of longer, eight-car electric trains in place of the six-car diesel trains currently in use.

The revisions to the programme will also secure services between Glasgow and Maryhill, which faced being squeezed out of Queen Street station due to the constraints imposed by extra Glasgow-Edinburgh trains.

Passengers were also promised wifi, which will now be provided on all Glasgow-Edinburgh trains by the end of 2014. Some of the mothballed work could be delivered in "future phases", Transport Scotland said.

Transport Minister Keith Brown's announcement yesterday follows months of delays in awarding major contracts which were originally due to be signed off in February.

Mr Brown said: "We originally said 2016 and we're working with Network Rail to see if it can be delivered in that timescale."

He said the revisions to the EGIP project had been made in response to changed circumstances, including a planned overhaul of Queen Street and the need to tie in the project with ambitions to include Scotland in a planned high-speed rail network.

He said: "While the original EGIP plans were the best way of achieving these improvements at the time, the new proposals not only secure faster times between Edinburgh and Glasgow they will increase capacity, revitalise Queen Street station and protect local commuter services into Glasgow."

Colin Howden, director of sustainable transport charity Transform Scotland, said: "If completing these further phases is dependent on a new high-speed line reaching Scotland then the Government is simply kicking these promised investments into the long grass."

However, Gordon Matheson, leader of Glasgow City Council, said: "Initial plans suggested train services in the north of Glasgow would have been diminished by this investment. However, I am pleased the Transport Minister has given me a personal assurance that this will not be the case."

Nigel Wunsch, Network Rail's head of strategy and planning for Scotland, said: "We look forward to working with the Scottish Government and other partners to deliver this project."

The original EGIP proposals were for six trains an hour in each direction between Glasgow and Edinburgh, with the fastest journeys cut from 50 minutes to 37 minutes.