Nearly 5,000 people have signed a petition to stop a rail route being reinstated over a landmark viaduct.
The Manchester and East Midlands Rail Action Partnership (MEMRAP) has campaigned for the Peaks and Dales line to reopen between Matlock and Buxton.
The line includes the Monsal Viaduct in Derbyshire, which has been converted into a walking and cycling trail.
Campaigners said reopening the viaduct for rail use would mean losing "one of the most unique trails in the UK".
The Peaks and Dales line was closed in 1968, as part of cuts made as a result of the Beeching report.
Parts of the 8.5 mile (13km) route - which incorporates former railway tunnels, as well as the viaduct - became a traffic-free route in 1981 and attracts about 330,000 visitors a year - with a "significant increase" in visitors since lockdown.
But MEMRAP wants the government to invest in permanently reinstating the line across the Derbyshire Peak District.
Campaigners opposed to the plan said it threatened the future of the popular trail.
MEMRAP chief executive Stephen Chaytow said the rail line would "reconnect disconnected parts of central Derbyshire" and the organisation believed a railway would be "far more beneficial than just having the Monsal Trail as a leisure activity".
But he said MEMRAP did not want to see "the Monsal Trail lost" and its proposals would see the trail retained in "some capacity".
However, the viaduct and tunnels would have to be used for the line.
The proposal has been supported by Conservative High Peak MP Robert Largan.
But New Mills-based campaigner Lee Cooper Smith said: "The Monsal Trail is one of the most unique trails in the UK.
"Tourism is one of Derbyshire's most lucrative industries and if this trail was closed, it would miss out massively."
An online petition set up by Mr Cooper Smith has gained nearly 5,000 signatures.
Peak District National Park Authority's conservation and planning director John Scott said the railway line and the trail were "incompatible".
"It's hard to see how you can have the railway back and have the trail experience as it is at the moment," he said.
The authority, which owns the trail and is the designated planning authority, said it had not received a formal application for the infrastructure project.
- 28 January