The first of a new generation of longer, more efficient trains rolled into Brighton station .

The next-generation Class 700 train took its first-ever test run on national rail tracks, coming to Brighton from its depot at Three Bridges.

At 240m long, the 12-carriage train is half as long again as most Thameslink trains operating today.

It uses hollow axles to reduce weight and optimises power efficiency by recouping some of the energy generated by braking to power the train.

The late evening test run was a success with the new rolling stock being passed compatible with signalling, and further tests will follow before the trains come into service next year.

Govia Thameslink Railway Programme Director Keith Wallace said: "The train performed excellently. This test run is a real milestone in the government-sponsored Thameslink Programme which, from spring next year, will steadily give passengers these new, modern and spacious trains on the Thameslink route.

"Passengers at other stations on our Peterborough and Cambridge Great Northern routes into London will begin using these trains later on as will people elsewhere in the South East when the Thameslink network expands in 2018."

Siemens has delivered three 12-carriage trains to its purpose-built depot at Three Bridges, all of them pulled by locomotive through the Channel Tunnel from Germany.

The first trains will enter service on the Bedford to Brighton route in spring next year.

The introduction of the new 12 and eight carriage Class 700 trains will significantly increase capacity across all routes, providing 80 per cent more peak seats across the central London route, between Blackfriars and St Pancras where there will be up to 24 trains per hour in each direction in the peak.

Siemens Thameslink Programme Director Dave Hooper said: "We are delighted to see the Class 700 out on test on the mainline. This is significant step in our comprehensive testing programme, and is a result of a lot of hard work from the whole Thameslink team. We look forward to the Class 700 going into passenger service in spring next year."