Work has begun on an extension to the Docklands Light Railway (DLR) that will help London's 2012 Olympic bid.
The extension should be finished by 2009
The 2.5km extension will take the DLR to Woolwich Arsenal from George V station at North Woolwich.
It will run in two tunnels under the Thames and is a part of the Olympic Transport Strategy.
It will provide another connection to the main Olympic park and the Olympic venue at Excel London. It should be completed by 2009.
London's mayor Ken Livingstone said the work will also help regenerate the Thames Gateway area.
He added: "Simply bidding for the Games has brought forward a host of transport improvements - with the East London Line extension, the new £400m ticket hall at King's Cross, and the £91m package of improvements to the North London Line all given added momentum."
Seb Coe, Chairman of London 2012, said: "Our transport plan is a real strength in our bid and was given the thumbs-up by the IOC Evaluation Commission.
"I am delighted to see that we are yet again already delivering part of an extensive transport plan to ensure fast, frequent and reliable transport for the 2012 Olympic and Paralympic Games."