 In 1897 the DR obtained parliamentary permission to construct a deep @-@ level tube railway running between Gloucester Road and Mansion House beneath the sub @-@ surface line . The new line was to be an express route using electric trains to relieve congestion on the sub @-@ surface tracks . Only one intermediate station was planned , at Charing Cross , 63 feet ( 19 m ) below the sub @-@ surface platforms . No immediate work was carried out on the deep @-@ level line , and the subsequent take over of the DR by the Underground Electric Railways Company of London ( UERL ) and the resignalling and electrification of the DR 's routes between 1903 and 1905 meant that congestion was relieved without needing to construct the deep @-@ level line . The plan was dropped in 1908 . 
