A glimpse of future rail travel has been unveiled as competition revved up to design and build a new fleet for First Capital Connect's (FCC) Thameslink route services.

The Department for Transport has invited four train manufacturers to tender for a new generation of locomotives demanding a challenging specification from the Department in conjunction with FCC and Network Rail. The investment will be the largest single order since the privatisation of Britain's railways.

The specification was drawn up using research with Thameslink passengers and special interest groups carried out on behalf of the independent national rail watchdog Passenger Focus in a joint project with London TravelWatch.

Manufacturers will have five months to produce detailed proposals and the winning bidder will be awarded a contract to build and maintain more than 1,200 carriages. These are expected to be delivered over three years, from 2012 to 2015.

Features include longer trains with greater capacity, more spacious interiors with wider connections between carriages, lighter energy-efficient vehicles with advances in safety and reliability built in.

FCC managing director Elaine Holt said: "This is a major step forward for the Thameslink programme that will transform our customers' journeys."