The Scottish Government has been accused of slashing planned improvements for one of the country's busiest rail lines with Labour claiming the project to upgrade the main Edinburgh to Glasgow route is a "shadow of its former self".
Elaine Murray, Labour transport spokeswoman, questioned whether changes to the programme's funding are the reason for it being scaled back and pressed Transport Minister Keith Brown over whether there was any connection to a request for a delay in loan repayments being turned down by the Office of the Rail Regulator.
The Edinburgh to Glasgow Improvement Programme (EGIP) was originally the subject of a £1 billion investment, including the electrification of 200 miles of track, which would have made it "an infrastructure project of major economic significance", she said.
Its budget "has been slashed by more than a third and only half the track planned for electrification will be electrified in the period between 2014 and 2019".
The programme is "now a shadow of its former self", Ms Murray said.
Mr Brown announced details of EGIP in July, saying the main line between Scotland's two largest cities would be electrified, reducing journey times by 10 minutes and improving reliability.
Longer trains are also promised for the busy route, with the Glasgow to Cumbernauld line to be electrified in time for the 2014 Commonwealth Games.
The programme would cost £650 million but changes now mean savings of £300 million on the original cost have been made. Ms Murray said those changes mean "there are more than a dozen elements of the original scheme now missing".
She added: "Plans for six electric trains per hour between Edinburgh and Glasgow have been downgraded to four diesel trains.
"The manifesto commitment was to more frequent services and faster services between Edinburgh and Glasgow including those of just half an hour. The current service offers four trains per hour with journey times between 50 and 55 minutes; 10 minutes off the fastest of those journeys is still 33% more than half an hour."