The Airports Commission's estimate of the cost of rail links needed to support the third runway at Heathrow airport is as much as £11 billion below that of Transport for London (TfL), according to newly released documents.
The documents, obtained by Greenpeace via a Freedom of Information request, show that the Commission based their estimate on the premise that the only rail cost associated with the third runway would be allowing Southern Rail access to Heathrow, which they estimated to cost £488m, or £810m allowing for optimism bias, reports Railway Technology.
However, TfL not only estimated the cost of Southern access to be £1.5-£2.5 billion, they also allowed for additional costs, such as T4 shuffle (worth £200 million, or £332 million with optimism bias), the Crossrail 2 extension (£2.9 billion, or £4.8billion) and a new rail link through Staines (£38 million or £64 million). In total, TfL estimated the railway costs of the third runway as £7-£12 billion.
Allowing for road costs as well, the Commission's estimate total estimate was £4.1 billion and TfL's was £18.2 billion. It is unclear who will pay these costs - Heathrow owners are meant to pay for infrastructure costs, but have said they will only pay £1.1 billion.