ON OCTOBER 27 UK Transport Secretary Alistair Darling named Hitachi as the preferred supplier of 'around 30' trainsets to operate 225km/h domestic services on the Channel Tunnel Rail Link. HSBC Rail (UK) Ltd is preferred financier.

The first four of the six-car trainsets are due to enter service in spring 2009, with the remainder being delivered later in the year. Based on Hitachi's A-Train concept, the high speed commuter trains have their origins in Japan's Series 400 'Mini-Shinkansen' sets, which were built to operate on high speed lines and over regauged conventional lines to serve towns off the high speed network. This mirrors the plans in the UK, where the trains would run from London to Ashford on the CTRL and then fan out on existing lines to serve destinations such as Ramsgate and Canterbury.

The journey time from Ramsgate to London St Pancras via Ashford and Canterbury will be cut to 1h 15min, compared with the current 2h to Victoria via Faversham and Chatham. Ashford - St Pancras will be just 34min, barely half the current 65min Ashford - Charing Cross timing.

In practice, there will few technical similarities with Series 400. For example, the Japanese trains had steel bodyshells, but the CTRL units will use the A-Train modular aluminium structure assembled using friction stir welding. Bogies will be derived from a Shinkansen design, but they will be heavier 'to cope with UK track conditions', according to Alistair Dormer, Business Development Director for the Rail Systems Industrial Group at Hitachi Europe.

The units will be able to operate in pairs. They will draw power at 25kV 50Hz on the CTRL and from the 750 V DC third rail on the connecting conventional lines. The four centre cars in each six-car set will be powered, with all axles motored to deliver a continuous rating of 3360kW. Pantographs will be mounted on the driving trailer cars.

Each set will seat between 300 and 354 passengers, and will feature air-conditioning, CCTV, pressure sealing, on-board information systems, selective door opening and full compliance with disability regulations. There will be one area for wheelchair passengers in each trainset, and one of the two toilet compartments will be disabled-accessible.

Internal layouts have yet to be agreed, and no decision has been taken on whether to provide first class. Streamlined front ends preclude the use of gangways at the ends of sets, and this may mean that the trains will not be able to run between Folkestone and Dover, where there are limited clearances in the single-track bores of Shakespeare Cliff tunnel. At present, only trains with end gangways are allowed to run through the tunnel, as there is no room to leave from a side door in an emergency.

The trains will be built in Japan, although a number of components will be sourced from Europe, according to Dormer. Testing will initially be carried out on a short standard gauge track at the Hitachi factory, and one option would see trains trialled on the Shinkansen before shipment to the UK.

The first train is due to arrive in mid-2007, allowing for 18 months of trials before public services start. This assumes that the contract will be signed in the next few months - Hitachi said in November that it did not expect to have the deal clinched before Christmas.

Hitachi will also be responsible for maintaining the trains, initially for the duration of the new Integrated Kent Franchise, and the company is expected to create around 70 jobs at a depot to be built in Kent.

Invitations to tender for the franchise are due to be issued later this year, once the required service pattern has been agreed by the Strategic Rail Authority. Initial consultations earlier this year generated considerable protest over the elimination of stops at many local stations and the reduction in services to the present London termini with the launch of faster trains to St Pancras.

• Fig 1. Driving trailer and two intermediate motor cars, showing the wheelchair accommodation and disabled toilet in car 2
• Fig 2. Train performance characteristics, with 790 mm diameter wheels and 24 kV supply