Nick Clegg has accused Chancellor George Osborne of a hollow commitment to the Transport in the North strategy as questions emerge over just how the projects will be paid for.
The plans build on the concept of the so-called HS3 and could see 140mph trains reduce Liverpool to Manchester journey times to around 20 minutes.
The Liverpool-Manchester option could cost as much as £13bn, while a plan to reduce journey times between Sheffield and Manchester from the current 48 minutes to 27 minutes could cost as much as £19bn.
Other plans include developing new east-west road connections including a road tunnel under the Peak District and introducing Oyster-style smart travel cards and simpler fares across the North.
Speaking to The Yorkshire Post, Mr Clegg said the Liberal Democrats would “without a doubt” borrow money in Government to fund those rail and road projects getting the go ahead.
The threat, he said, came from a Conservative party which will not consider borrowing for transport.
“The Liberal Democrats believe that we can afford to borrow for mayor infrastructure projects such as these, that is rightly the role of central Government.
“The Conservative position is very different to this. The only way they could afford to pay for even part of this is cut public services. They will not borrow for this, their only other option is to close schools for new roads.”
The Lib Dem leader said options in the report were far more likely to get the go ahead than the seemingly unplanned HS3 proposal favoured by the Chancellor.
Mr Clegg said: “The most impressive thing about this, I think, is that these are plans that everyone has signed up to.
“We have agreed a plan for years if not decades which will cover major infrastructure across the north, with some very ambitious schemes that Sheffield Council has played a significant role in bringing together.
“The projects identified here, such as the potential new rail and road tunnel under the Pennines, could have a dramatic impact on the economy of the north.
“I have always been interested in concrete ideas, quite literally here, for growth. We know how we will fund it, but or all the Chancellor’s Budget comments on the north, we do not know how they would fund this with cuts to public services in the north.”
As part of the announcement Transport Secretary Patrick McLoughlin has met with council leaders on the Rail North authority to sign over powers giving the group a much bigger say on the north’s two commuter rail franchises.
“We’ll be electrifying over 800 miles of railway over the next five years - the biggest electrification we’ve seen post-Victorian era,” he said.
“I was a junior minister in the Department for Transport 25 years ago, and the truth is railways were seen as yesterday’s business. Today, they’re an absolutely essential part of our economy and we’re giving support to them.”
Mr McLoughlin insisted that funding for the transport investment would not be affected by Mr Osborne’s plans for departmental spending cuts after the election.
“This is infrastructure investment,” said Mr McLoughlin. “We’ve already announced a rail investment strategy going up to 2019. It’s there. It’s built in.”