§ Chris Grayling
To ask the Secretary of State for Transport, Local Government and the Regions what assessment he has made of the ability of main line trains to operate on the sub-surface lines in London. 
§ Mr. Jamieson
Studies were undertaken by both Railtrack and London Underground Limited in 1999 when they were discussing Railtrack's proposals for the sub-surface infrastructure company under the PPP. It was concluded that: such a proposal would provide no additional net capacity; it would give rise to substantial costs in restructuring infrastructure and rewriting contracts; and, the interworking of mainline and existing tube rolling stock would give rise to technical and operational difficulties. Railtrack's proposals were subsequently abandoned.