Airports of London runways. Due to the location in London's western suburbs, Heathrow has had trouble trying to expand, with various expansion projects being cancelled.) As a result, the airport consistently runs at over 99% capacity and is often included on lists of the worst-rated airports in the world. However, on 1 July 2015 Heathrow's expansion plan was suggested as the best option by the Airport Commission and on 25 October 2016 a new northwest runway and terminal was approved by the Government. The airport is connected to Great Britain's motorway network via the M4 and M25 motorways, to London Paddington station by
Train protection system Train protection system A train protection system is a railway technical installation to ensure safe operation in the event of human failure. The earliest systems were train stops, as still used by the New York City Subway, the Toronto subway, the London Underground, the Moscow Subway (only on the older lines) and the Berlin S-Bahn. Beside every signal is a moveable arm. If the signal is red, levers connected to valves on any passing train hit the arm, opening the brake line, applying the emergency brake, If the signal shows green, the arm is turned away from the levers and