The route, which goes through the East Midlands, was due to be electrified but rising costs have halted the project.
Jon Ashworth, Labour MP for Leicester South, said people in the region feel let down by the decision.
Alberto Costa, Conservative MP for South Leicestershire, said he wanted to work with Mr Ashworth on the issue.
Mr Ashworth said: "Experts in the rail industry were warning about this back in November and it was in the Conservative Party manifesto.
"Cabinet ministers came to the Midlands to marginal seats and made these promises.
"That's why people feel let down."
Mr Costa said he was giving Transport Secretary Patrick McLoughlin time to speak with professionals ready for an update on the project.
He said: "Jon [Ashworth] and I stand as one, we want to see this and I'm happy to work with him on this."
Mr McLoughlin is due to be questioned by MPs over his decision on Monday.
The government is under pressure to reverse its decision to pause the £500m electrification of the Midland Mainline.