Planned improvements to rail services in and around Bristol are at risk as a result of the West Coast Mainline franchise delay, an MP has warned.
A decision to award the line to First Group was scrapped due to "technical flaws" in the bidding process.
Bristol West MP Stephen Williams (Lib Dem) said: "What I think is at risk is all the local improvements that we were looking forward to in Bristol."
Bidding for all British franchises is on hold while a review is carried out.
'Delay and congestion'
"There were those services on the Severn Beach line, maybe a line out to Portishead, lines across north Bristol and making better use of those railway lines that we already have in Bristol that are closed to passenger traffic," added Mr Williams.
Chris Irwin, from TravelWatch SouthWest, said: "Things that we as passengers would have benefited from, the promised new vehicles, the promised new station improvements, promised minor infrastructure improvements, can make a lot of difference to daily travel.
"Those have undoubtedly not happened now. When they do happen, there'll be years of delay and congestion to make up for."
Apart from the risk of losing planned local rail improvements, the cost of the delay is also being raised.
"We're right back at the drawing board. In terms of how it's going to move forward it's going to be hard to say how much it's going to cost.
"Some people say it's just the £40m the bids themselves cost, but if you talk to people in the industry they say 10 times the cost, but perhaps a 100 times might be a better figure - we might be talking billions," added Mr Irwin.
Four companies were bidding to run trains for 15 years from April: FirstGroup, Arriva, National Express and Stagecoach.
They were due to submit proposals, but the overall bidding review is not expected to report back to ministers until Christmas, which could delay the Great Western tendering.
Patrick McLoughlin, Secretary of State for Transport, said: "What has happened is unacceptable and deeply regrettable and all I can do is apologise.
"We have made a big mistake as far as the department is concerned."