Crossrail is a major new railway proposal that would link Maidenhead and Heathrow in the west with Shenfield and Abbey Wood in the east through new tunnels under central London.
It would bring major reductions in congestion and journey times for London and the South-East.
The proposed Crossrail Bill is currently being considered by a Select Committee in the House of Commons and a number of changes to the scheme are proposed to address petitioners' concerns, or otherwise improve the project design.
These are called 'Additional Provisions'.
Various public information centres were held along the proposed route between 11 September 2006 and 19 October 2006.