 In the Eastern region the plan called for electrification of many routes to this standard.These included the London, Tilbury and Southend (LTS) line; suburban lines out of London Liverpool Street, recently partially electrified on the 1.5 kV DC system, were upgraded initially to a mix of 6.25 kV AC and 25 kV AC OLE and extended.The London King's Cross suburban lines were electrified at 25 kV AC in the 1970s.