Firm pitches “an M25 for high-speed trains” to pass through Heathrow and Gatwick

A London-based engineering consultancy has proposed a transformative high-speed railway which would connect the major airports of the UK and enhance current transport infrastructure projects planned in the south-east.

Expedition has unveiled its plan for HS4Air, which connects the existing HS1 rail line to the planned HS2 rail line along a route that passes via both Gatwick and Heathrow airports. The project would also provide fast and direct rail access from major cities north and west of London including Birmingham, Manchester and Cardiff, while “dramatically reducing journey times”.

Those behind the proposal estimate the cost to be approximately £10bn and would provide relief for London’s rail network, on the M25 and the number of domestic flights involving Heathrow and Gatwick.

Expedition director Alistair Lenczner, who has led the development of the HS4Air proposal, believes the proposed network would provide better value for investments currently being made in the UK. The director presented his vision for HS4Air this week at an event held at the Institution of Civil Engineers.

“HS4Air has been developed to allow rail and aviation infrastructure projects in south east England that are currently unconnected to become joined-up,” Lenczner said. “In a way HS4Air can be regarded as a high-speed railway version of the M25 around London, except that it allows much faster journey times with no congestion and with far less impact on the environment”. The proposed HS4Air project is an example of integrated strategic planning that spans across multiple infrastructure sectors that are too often planned within separate “silos”.

The 140km long proposed network would run between its connections with HS1 at Ashford and its proposed connection with HS2 near Denham. Approximately 20% of HS4Air would run in tunnels to avoid adversely impacting on environmentally sensitive areas such as the Surrey Hills. 

A 15-minute surface transfer shuttle time between the airports using dedicated high-speed shuttles has also been identified as a benefit on the HS4Air railway. The fast and frequent shuttle services would make it possible for passengers to make convenient and reliable transfers between Gatwick and Heathrow and for airlines to share operations between the two airports.

Expedition has been responsible for major projects like the London Olympic Velodrome and the Infinity Bridge in Stockton-on-Tees. It now hopes to continue preliminary talks with interested parties both nationally and internationally.