The line linking Anniesland to Queen Street, and which runs through Maryhill and Possilpark, is in danger of being cut off from the city centre to allow more trains on the main line
Network Rail are consulting on the £1billion project to reduce journey times and increase the number of intercity trains.
But as a result, local services are likely to suffer and the line, opened in 2005 with new track and stations as part of a £35million project, could become useless if commuters look to alternative transport.
Patricia Ferguson, MSP for Glasgow's Maryhill and Springburn, fears that services will suffer as a result, and is concerned that the impact on the local line has not been mention- ed in the consultation.
Passengers may not be able to travel from stations on the line, such as Maryhill, Kelvindale and Parkhouse and Possilpark to Queen Street, as the increased number of mainline services would take priority. Instead they would have to travel in the other direction, to Anniesland where the branch line ends, then change to the line which goes through Partick and into Queen Street low-level, adding up to 30 minutes for the trip.
Ms Ferguson said the route would soon become economically inviable and could be axed.
She said: "I am extremely concerned about the impact that the Edinburgh to Glasgow Improvement Plan could have on the train service from Anniesland to Queen Street via Ashfield.
"I cannot imagine that people will be willing to travel from many of the stations on the line if they have to go to Annies- land to change trains to travel to Queen Street.
"It could add more than 30 minutes to what is currently a seven-minute journey."
"Network Rail and the Scottish Government are consulting on their proposals for the Glasgow to Edinburgh service but if travellers don't know all the consequences how can the consultation be fair?
"I have written to both the Minister and Transport Scotland seeking reassurance that they will not agree to proposals that could have such a detrimental affect."
Network Rail admitted that in order to put more trains between Glasgow and Edinburgh through the Queen Street tunnel, other services would almost certainly be affected.