Services from Cirencester were axed in the 1960s as part of the Beeching cuts leaving only services from the nearby village of Kemble.
But now, Cirencester Community Railway wants to raise funds for a feasibility study to lay four miles of track.
The plan involves a "light" rail service which would link to mainline services in Kemble.
Recently, a scheme to double the track at Kemble at a cost of £45m, was completed by Network Rail.
That route links Cheltenham, Gloucester and Kemble with Swindon and London Paddington.
And a light train service from Cirencester could link up to Kemble meaning people would not have to drive and park there.
The group's Richard Gunner said £75,000 is needed to fund a study to estimate how many people would use the service.
Cirencester mayor Mark Harris said the plan was at "very, very early stages" but added it would "free up the roads" and help with under-pressure parking in the town.
He added that the plan would also help link up the town with London and make it "so much easier" to do business with the capital.
The £13m proposal includes a new station in Cirencester at Chesterton and a bridge being built over the A429 at Kemble.
The scheme could also alleviate parking issues in Kemble where a small car park is often full with motorists having to park in nearby roads.
A Great Western Railway spokesman said the firm wanted to build a new car park.
"We are currently awaiting planning consent from Cotswold District Council which we understand should be granted shortly."
A Cotswold town could be linked to mainline rail services again if a plan for a new line is approved.