at a new Train Modification Unit (TMU) in Acton and is expected to complete in late 2023. Depots There are three depots: Ruislip, Hainault and White City. White City depot first opened in 1900 when the initial line went into operation; Ruislip and Hainault depots were completed in 1939. During the Second World War, anti-aircraft guns were made at Ruislip Depot and the U.S. Army Transportation Corps assembled rolling stock at Hainault between 1943 and 1945. As part of the construction of the Westfield London shopping centre, the depot at White City was replaced underground, opening in 2007. Services During the off-peak, services on the Central line are grouped by branch lines: trains on the West Ruislip branch run to/from Epping, while trains to/from Ealing Broadway run on the Hainault Loop. Services at peak times are less structured, and trains can run between any two terminus stations at irregular intervals (e.g. from Ealing Broadway to Epping). , the typical off-peak service, in trains per hour (tph), is: 9tph between and ; 3tph between and ; 3tph between and ; 6tph between Ealing Broadway and (via ); 3tph between Ealing Broadway and Newbury Park; 3tph between and Hainault. The above services combine to give a total of 24 trains per hour each way (one every 2 minutes and 30 seconds) in the core section between White City and Leytonstone. At peak times, the frequency increases further, with up to 35 trains per hour each way in the core section. A 24-hour Night Tube service began on the Central line on 19 August 2016, running on Friday and Saturday nights. Night tube services are: 3tph between Ealing Broadway and Hainault (via Newbury Park) 3tph between White City and Loughton Peak-time frequency In September 2013, the frequency in the morning peak period was increased to 35 trains per hour, giving the line the most intensive train service in the UK at the time. Before that date, the Victoria line held the record with 33 trains per hour; it regained it in May 2017 with an increased frequency of 36 trains per hour (one every 100 seconds) during peak periods. Future and cancelled plans The Central crosses over the Metropolitan and Piccadilly lines' shared Uxbridge branch near West Ruislip depot, and a single track linking the two routes was laid in 1973. The London Borough of Hillingdon has lobbied TfL to divert some or