The Labour party has called on ministers to delay the singing of a new contract on the West Coast Mainline franchise until parliament returns from its summer recess.
The move follows a controversial decision to take the franchise from Virgin Trains and give it to FirstGroup for the next 13 years.
Labour argues MPs must be given a chance to consider the decision.
However, the department for transport said it had “no reason” to delay the signing.
FirstGroup says it will bring in key improvements for passengers on the line when it takes over the franchise later this year.
However, critics fear it will not be able to afford the £5.5 billion it is paying for the franchise.
Virgin has offered to run the franchise “for free” if the signing is delayed and a review of the tender process is carried out.
Aberdeen-based FirstGroup already operates a number of rail routes including Great Western and ScotRail.