Printed in turquoise on the Tube map, it is by far the shortest line on the Underground network, being 2.37 km (1.47 miles) long,[2] with an end-to-end journey lasting just four minutes.

The London and South Western Railway (LSWR) reached Waterloo Bridge on 11 July 1848, serving routes from Southampton and Richmond.

In November 1891, a bill was deposited to build an underground electric railway from Waterloo to the Mansion House in the City; the capital was to be £500,000; the proposal was supported by the LSWR but was independent.

The progress of the bill through Parliament was slow, partly because of the novelty of considering tube railway schemes; there were several petitions from the authorities responsible for public works in the city.

Numerous petitions against the bill, or requiring additional protections to be included in it, were presented, but eventually on 27 July 1893, the Waterloo and City Railway Act 1893 (56 & 57 Vict.

[15] The excavated material was removed from the staging near Blackfriars Bridge; it was conveyed there from the shields by a narrow gauge railway using electric locomotives supplied by the Siemens Company.

The curve is constructed by cut-and-cover, and the twin tubes start immediately after it, under Stamford Street, turning north-north-east to pass under the River Thames, converging with Blackfriars Bridge on the north bank.

Each 20-inch (510 mm) long section of tunnel wall was formed with a cast iron ring, made from seven segments and a key piece at the top.

There were five boilers working at 180 psi (1,200 kPa) driving five (later six) high speed steam engines developing 360 hp (270 kW) directly coupled to dynamos.

This obviously referred to the Waterloo & City line, and was designed to create a single station frontage in the congested street area.

"[19]The W&CR station was located some considerable distance from the area near street level, and this later led to persistent complaints as it required passengers to climb a steep and lengthy gradient to reach the exit.

Designed by the LSWR Chief Mechanical Engineer, Dugald Drummond it had two four wheel bogies and was intended for the rescue of failed passenger trains in the tunnel.

In 1915, it was removed from the tunnel and put to work shunting coal wagons at Durnsford Road power station, having had its shoe collectors altered for the surface traction supply system.

The procedure is now carried out using a road-mounted crane in a shaft adjacent to the depot, south of Waterloo main line station on Spur Road.

The driving cabs were half width; the traction motors, two per car, were 75 hp (56 kW) nose suspended with single reduction gear.

[27] When the line was built, the platforms at Bank (then known as City) were located a considerable distance from the surface exits, and a long sloping tunnel had to be negotiated on foot.

After considerable delay considering this and alternatives, British Railways let a contract on 4 July 1957 for the civil engineering works in driving a new sloping access tunnel, in which a pair of travolators (at the time often written Trav-O-Lator) would be installed by Waygood Otis.

In association with the work, some improvements were made to the station environment at the Waterloo station, and a 2+1⁄2 minute frequency was implemented in the peaks; this involved some minor signalling changes, reversion to alternating platform use at Bank, and the use of turnover drivers and guards (where the arriving driver and guard are replaced by staff waiting at the appropriate place for the change of direction, sometimes referred to as "stepping up").

In January 2003, the Waterloo & City was closed for over three weeks for safety checks after a major derailment on the Central line, which required all 1992 tube stock trains to be modified.

[37][38] Four new 75 hp (56 kW) battery-powered locomotives, named Walter, Lou, Anne and Kitty, were built by Clayton Equipment in Derby to haul materials and plant along the line during the closure.

[43][44] In March 2020, following the UK government's implementation of lockdown restricting all non-essential travel due to the COVID-19 pandemic, the Waterloo & City line was suspended.

[49] By March 2021, TfL stated that they expected the line to return to operation in May or June 2021, observing that services could be restarted at short notice if required.

As part of the total route modernisation project by Network SouthEast (NSE), the decision was taken to purchase new vehicles as an addition to an order for new 1992 Stock trains by London Underground for the Central line.

In the mid 2010s, TfL began a process of ordering new rolling stock to replace trains on the Piccadilly, Central, Bakerloo and Waterloo & City lines.

The lift for lowering rolling stock to the tunnel level, and some electrical work, were not ready, but on 4 June 1898 a successful trial run was made.

The two motors at each end were connected in series at starting, then reconnected in parallel (using open circuit transition) as the train accelerated in the well established (at that time) method.

A further cable making nine in all linked the collector shoes at opposite ends of the four-car set to avoid problems with the large gaps in the centrally mounted conductor rail.

The revised Working Party Report of 1965 did not mention the Route G proposal, though it does conclude that "[t]he possibility of extending the Waterloo & City line northwards to Liverpool Street has been examined, but found to be physically impracticable.

Download coordinates as: The Waterloo and City line is closed on weekends; as a result, it has become a well-established and convenient location for film companies.

[67] The origins of this nickname seem to be uncertain; it may be due to the tunnels beneath the Thames continually leaking and the resulting water needing to be pumped out,[4] or perhaps because passenger access to the platforms at Bank was by a lengthy sloping subway resembling a drain.