With connections to the Great Western Railway (GWR) and Great Northern Railway (GNR) under construction and connections to the Midland Railway and the LC&DR planned, the Met obtained permission in 1861 and 1864 for a four-track eastward extension to a new terminus at Moorgate and two additional tracks from King's Cross to Farringdon Street. The Met used two tracks for its own services, while the other two tracks were used mainly by other railway companies; these collectively became known as the City Widened Lines. A pair of single track tunnels at King's Cross connecting the GNR to the Met came into passenger use on 1 October 1863 when the GNR began running trains, those towards Farringdon Street calling at a single-platform station at King's Cross York Road, in the reverse direction at King's Cross Suburban station. A west curve towards Baker Street was built but not used for regular traffic and the track removed in 1865. Having withdrawn from running Metropolitan services on 10 August, the GWR returned on 1 October 1863 with through trains from such places as Windsor.