Coloured dark blue on the map and running from Heathrow and Uxbridge to Cockfosters, the Piccadilly line is the fourth busiest line on the Underground network, receiving 210 million passengers per year.
And its popularity is no surprise, really, given that it serves many of London's top tourist attractions, including Harrods, Hyde Park, Buckingham Palace, Piccadilly Circus, Leicester Square and Covent Garden, as well as London Heathrow Airport, the busiest airport in Europe.
If you live in London, you probably use this line to catch a flight from the airport, watch a football game at Arsenal, or take a weekend trip to Paris at King’s Cross St Pancras.
The Piccadilly Line is also due an upgrade next year, when it will welcome a new fleet of air-conditioned carriages with a slick new design and modern amenities.
The 94 new trains, which are part of TfL’s £3bn Piccadilly upgrade, will hopefully all be in operation by 2028.
Some of the new carriages are being built in Austria by Siemens before they’re due to be shipped to the UK at the end of 2024, where they’ll undergo overnight testing on the tracks.
The Piccadilly Line has been shuttling people around the capital for almost 120 years. It now has 51 stations and a route length of 70km, making it one of the longest lines on the Underground map.
So let’s take a look at the key moments that bring this line to where it is today.
1906: Piccadilly Line opens
Opened in 1906, this important transport link began life as the Great Northern, Piccadilly & Brompton Railway (GNP&BR), one of several railways controlled by the Underground Electric Railways Company of London.
Spanning 15.3km of twin tunnels at first, the line was an instantly popular route for those trying to efficiently get from A to B.
1911: London Underground’s first escalator
A few years after its grand opening, Earl’s Court station, which led to the Piccadilly Line, welcomed the Underground’s first “moving stairs”.
While this wasn’t the city’s first escalator, people reportedly gathered at each end and looked on in awe at the fantastic new contraption.
1920: The extensions begin
The original line initially ran from Finsbury Park to Hammersmith, but was extended in the 1920s to run to Acton Town following the existing District Line tracks.
And the extensions kept on coming.
South Harrow and Arnos Grove opened in 1932, while Hounslow West, Uxbridge, and Cockfosters were introduced in 1933, along with several impressive Art Deco-inspired stations.
1940: Special wartime uses
During the Blitz, parts of the Piccadilly Line were actually used to store artifacts from the British Museum.
The now abandoned Aldwych Underground station (which shut in 1994) served as both a bomb shelter and a storage place for treasures like the Elgin Marbles.
1975: Current fleet introduced
The Piccadilly Line has 86 1973 stock trains currently in action, which have been in operation since 1975.
While upgrades have been made since, replacement carriages would take another 50 years to be introduced.
1975: Airport connection added
Between 1975 and 1977, another section was added which extended to Heathrow Airport, making London the first city to have an Underground railway link to its airport.
Terminal 4 was added almost 10 years later, dramatically improving people’s access to the airport.
2008: Terminal 5 gets a station
Almost 30 years after the first airport connection was added, TfL finally got around to adding an extension to terminal 5.
Terminal 5 was added in 2008, giving Heathrow three Underground stations.
2014: Upgrades begin
By this point, it was clear that the old line needed some upgrades.
Demand and use of the line had soared, and TfL needed to keep up, so they started improving elements as part of Transport for London's (TfL) £10bn investment programme.
Mike Challis, Piccadilly Line general manager, said: "The upgrade will provide the line with a new signal control system, new trains and a new line control centre."
2021: Siemens unveils new generation of trains
In a live broadcast, TfL and Siemens unveiled the new designs for the Piccadilly Line trains.
The new designs feature spacious, air-conditioned walk-through carriages, better accessibility, and an all-around slicker design.
2025: New carriages begin to be introduced
While the first of the new fleet will be on the tracks by late 2024, they won’t be in public service just yet.
The 94 trains will be tested overnight to ensure operational safety before officially making their debut in 2025.
According to the Rail magazine, TfL plans to increase capacity by 23 per cent during peak hours by upping the number of trains.
