In terms of total passengers, the Central line is the second busiest on the Underground. In 2016/17 over 280 million passenger journeys were recorded on the line. It currently operates the second-most frequent service on the network, with 34 trains per hour (tph) operating for half-an-hour in the westbound direction during the morning peak, and between 27 and 30 tph during the rest of the peak. This makes the Central line the busiest and most intensively-used railway line in the United Kingdom: it is the only Tube line running east–west through the central core of London, running under Oxford Street and the financial centre of the City of London. Crossrail, due to begin most of its core operation in late 2020 or early 2021, will provide interchange with the Central line at Stratford, , , and Ealing Broadway. relieving overcrowding in these areas by providing passengers travelling longer distances with faster, and hence more desirable, services, leaving the Central line to only handle passengers making shorter journeys in Central London.