Indian commuters travel in a local train in Kolkata, India, Tuesday, February 26, 2013. Indian Railway Minister Pawan Kumar Bansal is presenting the country's rail budget for next fiscal year in the parliament Tuesday, Feb. 26, 2013. Indian railway network is one of the world's largest, with some 14 million passengers daily and some 64,000 kilometers (40,000 miles) of railway track cut through some of the most densely populated cities. (Photo by Bikas Das/AP Photo)

Soldiers from 12 Mechanized Brigade perform a simulated casualty evacuation at the Ministry of Defence training area at Copehill Down on Salisbury Plain on March 9, 2012 in Wiltshire, England. The Defence Secretary Philip Hammond visited the military facility to meet soldiers from the Brigade who are shortly to deploy to Afghanistan for Operation Herrick 16, and troops from the 3rd Battalion, the Yorkshire regiment which lost five of the six men who died this week in the deadliest single attack in Afghanistan since 2001. (Photo by Matt Cardy/Getty Images)

A female soccer player controls a ball during a training session at the Golab Trust Sport Complex in Kabul March 10, 2014. Despite decades of conflict in Afghanistan, and several recent militant attacks, the country's capital Kabul is home to a vibrant youth scene of musicians, artists, athletes and activists. Shopping malls and cafes stand in the city, which is nonetheless beset by infrastructure problems and instability. (Photo by Morteza Nikoubazl/Reuters)

Fred Fugen seen training for a jump over Austria on May 12, 2014. Fearless skydivers jump from an altitude of 10,000 meters above the largest mountain in Europe. Frederic Fugen, 34, and Vincent Reffet, 29, leapt from a plane in the freezing skies above Mont-Blanc in the French Alps. The jump is from such a height the pictures show the curvature of the earth. (Photo by Dominique Daher/Barcroft Media)

Participants hang from ropes as they learn how to use safety gears at an experience centre for construction safety training in Beijing, September 5, 2014. The centre which opened in June 2014 was established to educate workers about construction safety. According to the centre, about 1,000 construction workers undergo 3-hour classes which comprises of 33 modules every month. (Photo by Kim Kyung-Hoon/Reuters)

In this Friday, February 27, 2015 photo, an Israeli high-school senior preparing to join the Israeli military later this year participates in a privately run training camp for military combat fitness near Yakum, central Israel. With a mandatory three-year military service looming after graduation, teenage boys, and increasingly girls too, are gearing up for the draft, getting into shape and trying to improve their chances of acceptance into elite combat units. (Photo by Oded Balilty/AP Photo)

Chinese paramilitary guards monitoring passengers as they head to their train to travel to their hometowns for the “Spring Festival” or Lunar New Year at Nantong Railway Station in Jiangsu province, near Shanghai Travellers taking part in the world' s largest annual human migration must be home by January 27 to usher in the new year on January 28. (Photo by AFP Photo/Stringer)

A light railway train passes through a residential building on March 18, 2017 in Chongqing, China. Chongqing Rail Transit No.2 and a 19-storey residential building have been built across each other. The railway set its Liziba Station on the sixth to eighth floor in the building with noise reduction equipment. (Photo by VCG/VCG via Getty Images)