Park Record Media Center

Interior of an all-steel London underground train circa 1920. (Photo by Topical Press Agency/Getty Images)

Unrecognized by passers-by, Britain's Princess Elizabeth, left, and her sister Princess Margaret, are taken for a walk through busy London streets on May 15, 1939, after their first ride on a London Underground train. They were accompanied by their governess and a lady-in-waiting. (AP-Photo)

Great steel doors have been built into the tunnels of London's Tube railways, deep below the city, to prevent flooding caused by bomb damage to sewers, water mains and river culverts. This explains the closing of some of the tube stations since war began. Huge floodgates built in one section of London's Tube in this case to resist possible flooding from the River Thames, Oct. 5, 1939. These gates will withstand a pressure of 800 tons, more than any possible pressure they will be called on to bear. (AP Photo)

Londoners sheltering in a London Underground station from the Nazi bombing raids, play cards through the night to pass the time, Sept. 25, 1940. (AP Photo)

Londoners sleep on stationary escalators in a London Underground station during Nazi bombing raids on Sept. 27, 1940. (AP Photo)

Londoners sleep on the platform and on the train tracks at Aldwych Underground station, London, during heavy all-night Nazi bombing raids, Oct. 8, 1940. (AP Photo)

London children enjoying themselves at a Christmas Party on Dec. 25, 1940 in an underground shelter. (AP Photo)

Shelter life is now fully established once more with the coming of the long dark on Oct. 18, 1941 in London's biggest air raid shelter, in the making of which part of a tube tunnel has been utilized. Communal life is here seen in many phases, for boredom has to be defeated as well as Hitler during the long winters underground. A general view of this mammoth London shelter, showing the many people who are already using it in case the blitzes start again-sitting on their bunks before settling down for the night. (AP Photo)

Sheltering from air raids at Bound's Green Underground station, London on Dec. 5, 1940. (Photo by M. McNeill/Fox Photos/Getty Images)

A canteen in one of London's new deep underground air raid shelters on Oct. 20, 1942. Note the line of bunks which are convertible into seats on the left wall. (AP Photo)

A bomb crashed through the street surface outside the Mansion House and the Bank of England in London on Jan 11, 1941 causing the Bank subway to cave in. The underground station booking-hall was wrecked, a number of people were killed and others trapped. Later Royal Engineers threw a temporary bridge across the crater. (AP Photo)

London transport underground train driver Mr. Earnest Coulson, 60, who has 41 years of service with London transport, takes his hands from the controls of the tube train as it was guided by electronic impulses on the 'shuttle' section of the Woodford-Hainualt line in London, United Kingdom, on Feb. 19, 1968. The train picks up coded impulses from the main track which causes the train to accelerate, coast and brake to a halt at the next station, obeying all instructions given on the way, and slowing down or stopping or restarting as required if there is another train or a speed restriction on part of the route. The train operator, stationed in the front cab, closes the doors and presses the twin 'start' buttons at the beginning of the run. He can also take over the in the event of failure of the automatic equipment. (AP Photo/Victor Boyton)

An underground sign is pictured next to the "Big Ben" clock Tower on July 24, 2012, in London three days before the start of the London 2012 Olympic Games. The London Underground train system, affectionately known as the Tube, celebrates its 150th anniversary on January 9, 2013 bursting at the seams with four million passengers a day but undergoing modernization works to bring it into the 21st century. JOHANNES EISELE/AFP/Getty Images

A lone person stands in front of the locked gates at Victoria Underground station in London Wednesday evening November 20, 1996, after a system-wide power cut meant that thousands of passengers were stranded on subway trains. London Underground was planning an emergency regeneration of the system, to allow all trains to reach stations. (AP Photo/Rebecca Naden/PA)

Passengers pack onto a Central line underground train at Tottenham Court Road Station in central London. The London Underground train system, affectionately known as the Tube, celebrates its 150th anniversary on January 9, 2013 bursting at the seams with four million passengers a day but undergoing modernization works to bring it into the 21st century. ANDREW COWIE/AFP/Getty Images

In this file picture taken on March 29, 2001 Piccadilly Line underground trains stand parked outside Northfields Depot in west London. The London Underground train system, affectionately known as the Tube, celebrates its 150th anniversary on January 9, 2013 bursting at the seams with four million passengers a day but undergoing modernization works to bring it into the 21st century. ADRIAN DENNIS/AFP/Getty Images

Emergency services are seen outside the main line station at Kings Cross following an explosion which has ripped through London's tube network on July 7, 2005 in London, England. Blasts have been reported on the underground network and double decker buses in the capital. (Photo by Dean Mouhtaropoulos/Getty Images)

Passengers are evacuated from an underground train in a tunnel near Kings Cross station in London, Thursday, July 7, 2005. At least 33 people were killed Thursday in three explosions in London's subway system, a senior police official said. Deputy Assistant Commissioner Brian Paddick said others died in an explosion on a bus in central London but gave no figures. The second blast, at 8:56 a.m., in the King's Cross area of north London, killed 21, Paddick said. (AP Photo / Alexander Chadwick)

Maintenance workers tidy up after welding track joints in a tunnel on the Victoria line Underground railway on November 18, 2008 in London. Four million passengers use London Underground daily. 268 stations are served by the famous 'Tube' trains on 400 KM of track. The world's oldest underground railway is currently undergoing a multi billion pound investment program to upgrade the track, signals and stations. (Photo by Peter Macdiarmid/Getty Images)

A passengers walks for a train past Sherlock Holmes themed tiles at Baker Street Underground Station on January 9, 2013 in London, England. The London Underground commonly called the Tube, is the oldest of its kind in the world, and marks it's 150th anniversary. The network carries approximately a quarter of a million people around its network of 249 miles of track every day. The Baker Street station has more platforms than any other on the network with 10, and is one of the oldest of the 270 stations on the entire network. (Photo by Dan Kitwood/Getty Images)

A passenger uses the escalator to the platforms at St John's Wood Underground Station, in London on January 9, 2013. The London Underground celebrates 150 years since the first underground journey took place on January 9, 1863. REUTERS/Andrew Winning

A restored steam engine travels into the Baker Street underground station in central London on December 16, 2012. The engine, known as the Metropolitan Steam Locomotive No. 1 and built in 1898, was on a practice run in advance of celebrations to commemorate the 150th anniversary of the first underground railway journey on January 9, 1863. The journey took place through the new tunnels of the Metropolitan line between Paddington and Farringdon. Photograph taken on December 16, 2012. REUTERS/Paul Curtis/Transport for London/Handout

People walk by the Farringdon underground station, in London. The world's first subway system marked its 150th anniversary Wednesday, Jan. 9, 2013, with reports showing conditions way back when were much as they are today: Busy, congested and stressful for passengers. (AP Photo/Alastair Grant)

Passengers wait for a train at Baker Street Underground Station on January 9, 2013 in London, England. Baker Street Station shares the 150th Anniversary of its opening on January 10th, 2013 with the London Underground. Commonly called the Tube, the London Underground is the oldest of its kind in the world and now carries approximately a quarter of a million people around its network of 249 miles of track every day. Baker Street station was remodeled between 1911-13 by architect Charles W Clark to its present form as part of a comprehensive rebuilding project by the Metropolitan Railways with the station as its new company headquarters and flagship station, where it quickly became known as the ‘Gateway to Metro - Land’. Outside the Marylebone Road exit, a large statue commemorates Sherlock Holmes, Sir Arthur Conan Doyle's fictitious detective who resided at 221B Baker Street in the novels. (Photo by Dan Kitwood/Getty Images)

A plaque inside the Baker Street Underground Station on January 9, 2013 in London, England commemorates the 150th Anniversary of its opening on January 10th, 2013 with the London Underground. Commonly called the Tube, the London Underground is the oldest of its kind in the world and now carries approximately a quarter of a million people around its network of 249 miles of track every day.(Photo by Dan Kitwood/Getty Images)

Passengers use the escalator at Paddington Underground station, passing posters highlighting London Underground's 150th anniversary, in London on January 9, 2013. London Underground celebrates 150 years since the first underground journey took place between Paddington and Farringdon on January 9, 1863. REUTERS/Andrew Winning