Improving access to Heathrow Airport by train is an important environmental objective for the airport and London. Large numbers of passengers arrive at or depart from the terminals by car, contributing to congestion and poor air quality in the area.

Backed by AECOM, Heathrow Southern Railway Limited intends to create fast and easy rail access to Heathrow Airport from the south by building 8-miles (13-kilometres)  of new railway following the M25 motorway corridor between the Terminal 5 station and the existing South Western rail network. We expect most of the new line to run in tunnel to minimise environmental impacts. This short section of new infrastructure would have disproportionate benefits, for the first time directly connecting the UK’s only hub airport to its major markets to the south.

The UK government has now supported a third runway at Heathrow to facilitate a substantial increase in flights and passenger numbers. An increase in the proportion of surface access journeys by public transport is an important aim for the airport, with a target of 55% by 2040. While rail connections from the airport to central London are good — with Heathrow Express, the Piccadilly Line and, from 2019, the Elizabeth Line — rail services from the south are non-existent. Heathrow Southern Railway aims to change that.