Hopes are high for an improved rail service through west Wiltshire as the popularity of a Sunday seaside train proves there is demand in the region.

First Great Western is trialling the Summer Sunday Seaside Special which goes through Melksham, Trow- bridge and Westbury on Sunday mornings en route to Yeovil, Dorchester and Weymouth and back.

The service, which began in July and will run until August 28, has proved popular, with extra carriages needed for the hundreds using the service.

Campaigners hope the success will lead to a better service when rail franchises are decided in 2013.

Paul Johnson, chairman of the Strategic Economic Partnership, and member of the Wessex Chamber of Commerce, said: “It’s looking really positive, and the time is now because of the franchise allocation. We think the demand is there, it’s effectively three times what First Great Western thought it might be.”

The train is an extension of the service normally running from Westbury, but First runs it up to Swindon and back beforehand to allow extra passengers to embark.

The TransWilts line runs from Swindon to Salisbury via Chippenham, Melksham, Trowbridge, Westbury and Warminster, but there are only two services each way on the middle section.

Mr Johnson said the business case for extra trains on the line during the week was strong, which was now being backed up by demand for the weekend service.

Graham Ellis, from the TransWilts Community Rail Partnership, said: “Someone was asking me if this was the most successful seaside train First is running this summer. It could well be.”

The train leaves Swindon every Sunday at 8.20am and calls at Chippenham at 8.35am, Melksham at 8.45am, Trowbridge at 8.55am and Westbury at 9.12am.

The return train leaves Weymouth at 5.56pm. An adult day return from Swindon is £15.60.