Tilting trains could run from HS2 onto the rest of the rail network

Alstom has said its tilting train design would be suitable for the project and would allow for increased speeds

Alstom has said its TGV high-speed tilting trains could solve potential issues with rolling stock travelling from the HS2 line onto existing rail infrastructure.

The competition for the £7.5 billion contract to design and build HS2 rolling stock is expected to launch next year, with a mix of “classic-compatible” trains that would run across HS2 and the existing network and “captive” trains that would operate just on the high-speed line.

Alstom, which has already put forward an idea for a double-decker captive train, has said its tilting train design would be suitable for HS2 and allow for increased speeds when running from the high-speed route onto traditional lines.

The train would be based on the design it is making for the US Amtrak network.

Jaime Borrell, product manager of high-speed trains at Alstom, said: “If the priority for HS2 is journey time, including on tracks outside of HS2, then the tilting system can bring time reduction.”

Alstom’s Tiltronix anticipative tilting technology allows the train to manoeuvre around curves safely and more comfortably up to the maximum speeds set for the line. Trains usually slow down on curves to prevent unpleasant lateral acceleration. “We can run analytics and upgrade the overall speed of the line to reduce journey time,” said Borrell. “It is then the choice of the operator to fully dedicate the saved journey time to the final trip or to keep some margin back to increase punctuality on the line.”

Alstom’s tilting trains have been built to achieve mainline speeds of around 300km/h – the HS2 trains are expected to travel at up to 360km/h. However, Borrell said Alstom is able to develop tilting trains capable of faster speeds.

HS2 said: “There are no technical barriers to our specification for a classic-compatible train to have the same high-speed performance as a captive train running only on HS2.”

Last month, Professor Roderick Smith of Imperial College London said that running classic-compatible trains on and off the high-speed line would create pinch points, where late-running trains would delay HS2 trains as they transferred from the existing network.