Scotland's latest push to overhaul intercity railways must be about more than "money-grubbing," a leading union has warned.

Transport union RMT offered a note of caution yesterday in the wake of pressure groups' calls for "a rail revolution."

Umbrella body Transform Scotland's newly launched "intercity express" campaign has pressed Scottish ministers for increased investment in the nation's rail infrastructure, with demands ranging from electrification and doubling of rail lines to a direct rail link between Perth and Edinburgh, all in a bid to reduce travel times.

Transform's members include industry bodies, consumer group Passenger Focus, environment charity RSPB Scotland and cycling organisations.

Spokesman Paul Tetlaw said the overhaul promised "a safe, civilised and sustainable mode of transport" for Scotland in the 21st century.

"In doing so, we can reduce journey times, support travellers and commuters, create jobs, support the Scottish economy and reduce Scotland's carbon emissions," he added.

But RMT general secretary Bob Crow said unions had to be "at the heart of the discussion on future plans for rail in Scotland, not on the periphery."

The new developments were not an excuse to cut staff or erode pay and conditions, he said.

"We would throw down the demand that any 'rail revolution' would have to be run under public control and in the public interest if it's not going to become just another money-grubbing opportunity for greedy private companies," he said.