question: What is the name of the designer of the locomotive used on the public rapid transit system serving London and some parts of the adjacent counties of Buckinghamshire, Essex and hertfordshire in the United Kingdom?
answer: John Fowler
context: Title: London Underground
  Passage: The London Underground (also known simply as the Underground, or by its nickname the Tube) is a public rapid transit system serving London and some parts of the adjacent counties of Buckinghamshire, Essex and Hertfordshire in the United Kingdom.
  Title: Rapid transit in Canada
  Passage: There are three heavy rail and three light rail rapid transit systems operating in Canada.  The Toronto subway was the first rapid transit system in Canada when it opened a 12-station line in 1954.  It has since grown to encompass three heavy rail lines and one intermediate rail line and has the most number of stations of any system in Canada with 69.  Construction has begun on the Eglinton Crosstown Line and the Toronto-York Spadina Subway Extension, which will add 28 new stations and a total of 27.6 km of new track.  Montreal introduced the Montreal Metro in 1966 and has now become the most popular rapid transit system in the country with 1,263,800 daily riders.  The Vancouver SkyTrain, an automated guided line, was opened in January 1986 for the Expo 86 world fair and is the longest rapid transit system in Canada with a system length of 79.6 km .  There are three light rail systems operating in Canada including systems in Calgary (the CTrain), Edmonton (the Edmonton LRT), and Ottawa (the O-train).  There is one light rail system under construction in Kitchener-Waterloo named Ion rapid transit.
  Title: Taoyuan Metro
  Passage: Taoyuan Metro (formerly Taoyuan Rail Transit and officially Taoyuan Mass Rapid Transit System) is a rapid transit system serving the Taoyuan City area in Taiwan.  The proposed network will consist of five lines.  The system opened for commercial service on March 2, 2017 with the opening of the Taoyuan Airport MRT.
  Title: Fowler's Ghost
  Passage: "Fowler's Ghost" is the nickname given to an experimental fireless 2-4-0 steam locomotive designed by John Fowler and built in 1861 for use on the Metropolitan Railway, London's first underground railway.  The broad gauge locomotive used exhaust recondensing techniques and a large quantity of fire bricks to retain heat and prevent the emission of smoke and steam in tunnels.
citations: London Underground Fowler's Ghost