Although not part of the Underground, the line connects with many Underground stations, with the project rebuilding and expanding several central Underground stations including Tottenham Court Road. The Tube was heavily affected by the COVID-19 pandemic in 2020. After growing concern that amongst the outbreak and despite government advice on social distancing, tube services were still crowded. All Night Overground and Night Tube services, as well as all services on the Waterloo & City line, were suspended from 20 March, and 40 tube stations were closed on the same day. The Mayor of London and TfL urged people to use public transport only if absolutely essential, so that it could be used by critical workers. London Underground brought in new measures on 25 March to combat the spread of the virus by slowing the flow of passengers onto platforms, which included the imposition of queuing at ticket gates and turning off some escalators. Even with these measures in place there was still criticism that, especially in the rush hour, some stations and trains were experiencing crowding; however, statistics showed that the tube was experiencing some of the lowest passenger journey numbers since the 1800s. The Northern Line Extension opened in September 2021, extending the Northern line from Kennington to Battersea Power Station via Nine Elms. The extension was privately funded, with contributions from developments across the Battersea Power Station, Vauxhall and Nine Elms areas. Goods traffic Goods trains ran over Metropolitan tracks from 1866 when the Great Northern Railway (GNR) and then the Midland Railways began a service to south of the Thames via Farringdon and Snow Hill tunnel. Goods depots were opened in the Farringdon area, accessed from the City Widened Lines. The GWR opened Smithfield Market Sidings in 1869, the GNR opened its depot in 1874, and the Midland in 1878. The Midland also negotiated running rights over the District Railway from the London & South Western Railway at Hammersmith to South Kensington in 1876 and in 1878 it opened coal depots at Kensington High Street and West Kensington. Goods traffic was to play an important part of Metropolitan traffic on the extension line out of Baker Street. In 1880, the Met started conveying coal from Finchley Road to Harrow. Goods and coal depots were provided at most of the stations on the extension line as they were built. Goods for London were initially handled at Willesden, with