Editing Advanced Passenger Train (section)

===APT-E===
{{main|British Rail APT-E}}
[[Image:APT-E.png|thumb|right|APT-E Power Car PC2 and Trailer Car TC1]]

While POP was proving the basic concepts, construction of the test train continued at the Derby lab. The set was sufficiently complete by late 1971 for an official naming ceremony, where it became the [[British Rail APT-E|APT-E]] (for Experimental). It made its first low-speed run from Derby to Duffield on 25 July 1972. Upon reaching Duffield, the [[Associated Society of Locomotive Engineers and Firemen|ASLEF]] union immediately "blacked" it, forbidding their members from doing any work involving the train. Their complaint was that the APT-E had a single operator's chair, which they took as evidence that BR was moving to single operator trains. A friendly inspector helped the team move the train back to Derby at night. This resulted in a one-day national strike that cost more than the entire APT-E project.{{sfn|Wickens|1988}}

By this point the POP had demonstrated a number of problems, and the engineers took the opportunity to start a major overhaul of the design. The main problem was the design of the non-driven bogies, which were not stable and could not be used for high speed runs. One power car was retained at the lab while the other and the two passenger cars were sent to the nearby [[Derby Works]] for modification. The main changes were to stiffen the power cars and replace the suspect bogies with a version of the powered bogie with the motors removed. Other changes included the removal of the ceramic [[recuperator]]s from the turbines for reliability reasons, although this dramatically increased fuel use, and the addition of a small seating area to the passenger car for VIP use.{{sfn|Gilchrist|2006|p=34}}

Contract negotiations over high speed rail had concluded in the summer of 1973, just in time for the modified three-car APT-E to emerge from the shop in August 1973. The train then started a testing series lasting eight months, covering details of the suspension, braking, curve performance and drag. However, reliability was a serious problem and it returned to the shops for a second overhaul in March 1974. Among the many changes for this round was the switching of the turbines formerly dedicated to power delivery for the passenger cars to add additional power to the traction motors, while at the same time replacing all of the turbines with an upgraded {{convert|330|hp}} version, improving total power per car from {{convert|1200|to|1650|hp}}. Other changes included new motor bearings and the return and similar modification of the second power car, formerly used at the lab.{{sfn|Gilchrist|2006|p=34}}

The rebuilt four car train returned to service in June 1974. On 10 August 1975 it hit {{convert|152.3|mph|km/h|abbr=on}}<ref name=BBCcoverarticle>{{cite web |url = http://www.bbc.co.uk/northyorkshire/travel/story/tilting_train/index.shtml |title = To tilt or not to tilt |work = [[BBC News]] |access-date = 3 September 2009 |archive-url = https://web.archive.org/web/20070208064717/http://www.bbc.co.uk/northyorkshire/travel/story/tilting_train/index.shtml |archive-date = 8 February 2007 |url-status = dead}}</ref> on the [[Western Region of British Railways|Western Region]] between Swindon and Reading, setting the UK record.{{sfn|Gilchrist|2006|p=34}} It then set the route record from Leicester to [[London St. Pancras]] in 58 minutes 30 seconds on 30 October 1975, at an average speed of just over {{convert|101|mph}} through this twisty route.{{sfn|Gilchrist|2006|p=34}} It was also tested extensively on the [[Midland Main Line]] out of St. Pancras and on the Old Dalby Test Track, where in January 1976 it attained a speed of {{convert|143.6|mph|km/h|abbr=on}}.

APT-E testing ended in 1976, and the single train was sent directly to the [[National Railway Museum]] in [[York]] on 11 June 1976.{{sfn|Gilchrist|2006|p=34}} During its testing it covered approximately {{convert|23500|miles}}, ending a career that is considered a success, but the train could not be said to have been extensively tested; in three years it covered less distance than the average family car would in that period. In comparison, the first [[TGV]] prototype, [[TGV 001]], also powered by gas turbines, covered {{convert|320000|km}} between 1972 and 1976.<ref name=flop>{{cite journal |first=Mick |last=Hammer |title=The high-speed flop |journal=New Scientist |date=1 August 1985 |page=46 |url=https://books.google.com/books?id=_4SXKOBgJ_kC&pg=PA46 |access-date=8 February 2016 |archive-url=https://web.archive.org/web/20161103220415/https://books.google.ca/books?id=_4SXKOBgJ_kC&pg=PA46 |archive-date=3 November 2016 |url-status=live}}</ref>