The introduction of HS2 will "transform" service on existing train lines, Network Rail says.
Paul Plummer, group strategy director at the rail authority, said: "HS2 will sit at the heart of Britain's transport network, allowing us to reshape the railway in a way that incremental improvements simply cannot.
"That's why we welcome the report's recommendations and its call for an integrated approach to planning and operating the railway," he said.
Mr Plummer added: "The step-change in capacity that HS2 enables across the network as a whole will transform the service on existing lines, creating the space we need to meet growing demand and deliver new and better connections."
HS2 link requires too many compromises in terms of impacts on freight, passengers and the community in Camden, says Transport Secretary.
Despite pledging to find savings in the expensive High Speed 2 train line, the project's boss has failed to find significant financial cuts.