Question: Where did George IV of the country where the National Rail is from died?

full_context: Document 1: Railtrack: Railtrack was a group of companies that owned the track, signalling, tunnels, bridges, level crossings and all but a handful of the stations of the British railway system from 1994 until 2002. It was created as part of the privatisation of British Rail, listed on the London Stock Exchange, and was a constituent of the FTSE 100 Index. In 2002, after experiencing major financial difficulty, most of Railtrack's operations were transferred to the state - controlled non-profit company Network Rail. The remainder of Railtrack was renamed RT Group plc and eventually dissolved on 22 June 2010.
Document 2: The Copper Horse: The northern end of the Long Walk is at the George IV Gateway at Windsor Castle. The Copper Horse is a statue of George III on horseback, and is said to represent George as an emperor in the Roman tradition riding without stirrups, along the lines of the Equestrian Statue of Marcus Aurelius. A comparison has also been made to the equestrian statue of Peter the Great in Saint Petersburg.
Document 3: APTIS: APTIS was the Accountancy and Passenger Ticket Issuing System used on the British Rail/National Rail until 2007. It was originally called "Advanced Passenger Ticket Issuing System" as it was being developed at the time of the Advanced Passenger Train.
Document 4: Rail transport in Great Britain: In the 2015 -- 16 operating year, franchised services provided 1,718 million journeys totalling (64.7 billion billion passenger km) of travel, an increase over 1994 -- 5 of 117% in journeys (from 761 million) and just over doubling the passenger miles. The passenger - miles figure, after being flat from 1965 to 1995, surpassed the 1947 figure for the first time in 1998 and continues to rise steeply.
Document 5: BusPlus: BusPlus is the payment method for the GSP Belgrade, Belgrade tram system, Lasta Beograd (only in public transport in Belgrade) and BG TRAIN. It is a thin, plastic card on which the customer electronically loads fares. The BusPlus is managed by company Apex Technology Solutions. Public authorities state that BusPlus was implemented to increase the revenue of the public transit authority and to improve the public transport system by getting better information on usage. Reports from September 2012 have indicated that the overall revenue has increased, but some aspects of integration have been criticized by public. System is installed by Kentkart, an automatic fare collection system integrator company.
Document 6: British Rail sandwich: The British Rail sandwich has been used as a negative point of comparison for other ready-to-serve meals, especially regarding transportation in the United Kingdom, and representative of the negative effects of British nationalisation of industry in the middle of the 20th century. A 1997 article in "The Independent" referred to the sandwich as "an indictment of statist, bureaucratic corporations" privatised by Prime Minister Margaret Thatcher, who had "swept aside James Callaghan, prices and incomes policies and the British Rail sandwich".
Document 7: London Passenger Transport Board: The London Passenger Transport Board (LPTB) was the organisation responsible for local public transport in London and its environs from 1933 to 1948. In common with all London transport authorities from 1933 to 2000, the public name and brand was London Transport.
Document 8: British Railways Board: The British Railways Board (BRB) was a nationalised industry in the United Kingdom that operated from 1963 to 2001. Until 1997 it was responsible for most railway services in Great Britain, trading under the brand name British Railways and, from 1965, British Rail. It did not operate railways in Northern Ireland, where railways were the responsibility of the Government of Northern Ireland.
Document 9: The Horses of Helios: The Horses of Helios, also known as The Four Bronze Horses of Helios, is a bronze sculpture of four horses by Rudy Weller. It is one half of a commission installed in 1992 when the adjacent Criterion Theatre was refurbished. The other half, the "Daughters of Helios" or "Three Graces", is a sculpture of three women leaping off the building six stories above.
Document 10: The Sun (United Kingdom): Despite its initial opposition to the closures, until 1997, the newspaper repeatedly called for the implementation of further Thatcherite policies, such as Royal Mail privatisation,[verification needed] and social security cutbacks, with leaders such as "Peter Lilley is right, we can't carry on like this",[verification needed] The paper showed hostility to the EU and approval of public spending cuts, tax cuts, and promotion of right-wing ministers to the cabinet, with leaders such as "More of the Redwood, not Deadwood".
Document 11: Railtrack: Railtrack was a group of companies that owned the track, signalling, tunnels, bridges, level crossings and all but a handful of the stations of the British railway system from 1994 until 2002. It was created as part of the privatisation of British Rail, listed on the London Stock Exchange, and was a constituent of the FTSE 100 Index. In 2002, after experiencing major financial difficulty, most of Railtrack's operations were transferred to the state-controlled non-profit company Network Rail. The remainder of Railtrack was renamed RT Group plc and eventually dissolved on 22 June 2010.
Document 12: Regisole: The Regisole ("Sun King") was a bronze classical or Late Antique equestrian monument, highly influential during the Italian Renaissance but destroyed in 1796. It was originally erected at Ravenna, in what is now Italy, but was moved to Pavia in the Middle Ages, where it stood on a column before the cathedral, as an emblem of communal pride and Pavia's deep connection with imperial Rome.
Document 13: Pub: Quality dropped but variety increased with the introduction of microwave ovens and freezer food. "Pub grub" expanded to include British food items such as steak and ale pie, shepherd's pie, fish and chips, bangers and mash, Sunday roast, ploughman's lunch, and pasties. In addition, dishes such as burgers, chicken wings, lasagne and chilli con carne are often served. Some pubs offer elaborate hot and cold snacks free to customers at Sunday lunchtimes, to prevent them getting hungry and leaving for their lunch at home.
Document 14: Equestrian statue of Theodore Roosevelt: Equestrian Statue of Theodore Roosevelt is a 1939 bronze sculpture by James Earle Fraser. It is located at the American Museum of Natural History, New York City. The equestrian statue depicts Theodore Roosevelt on horseback. Standing to either side of him are an American Indian and an African.
Document 15: Equestrian Portrait of Charles I: The Equestrian Portrait of Charles I (also known as Charles I on Horseback) is an oil painting on canvas by Anthony van Dyck, showing Charles I on horseback. Charles I had become King of England, Scotland and Ireland in 1625 on the death of his father James I, and Van Dyck became Charles's Principal Painter in Ordinary in 1632.
ground_truth: Windsor Castle
sub_queries: National Rail >> follows Answer: British Rail
What is the country British Rail sandwich is from? Answer: United Kingdom
George IV of United Kingdom >> place of death Answer: Windsor Castle