Editing Advanced Passenger Train (section)

===Further development===
In 1981, BR hired the consulting firm Ford & Dain Partners to produce a report on the APT project and make any suggestions to improve it. It produced an interim report in November 1981, and a final version that December.<ref>{{cite tech report |title= Advanced Passenger Train: interim report by Ford and Dain Partners |date=November 1981 |url=http://discovery.nationalarchives.gov.uk/details/record?catid=8412824}}</ref><ref>{{cite tech report |title= Review of the Advanced Passenger Train: final report by Ford and Dain Partners |date= December 1981 |url= http://discovery.nationalarchives.gov.uk/details/r/C11183015 |access-date= 9 February 2016 |archive-url= https://web.archive.org/web/20161104011058/http://discovery.nationalarchives.gov.uk/details/r/C11183015 |archive-date= 4 November 2016 |url-status= live}}</ref> Their reports first suggested that the technical aspects of the design were largely complete, although they drew attention to the braking system, but that the management structure was a serious problem and there had to be a single manager in charge of the entire project. This resulted in the appointment of John Mitchell to the position of manager of the APT.{{sfn|Wickens|2002}} Matters immediately improved.

Among the improvements was a fix for the motion sickness being experienced by passengers. The commissioning team had been well aware of this problem before it entered service, but this was not mentioned to the press when it was noticed on the public runs. The problem was due to two effects. One was that the control system did not respond instantly, so the cars tended to not respond when the curve first started, and then reacted rapidly to make up for this lag. The fix for this was to take information on the tilt from the car in front, giving the system the slight time advantage it needed. The other problem was similar to [[sea sickness]], but in reverse. Sea sickness is caused when the body's [[equilibrioception]] system can feel movement, but inside a closed room this movement cannot be seen. On APT, one could easily see the tilting as the train entered turns, but there was no perception of this motion. The result was the same, a confusion between the visual and the equilibrioception system. The solution was almost trivial; slightly reducing the amount of tilt to be deliberately less than needed resulted in a small amount of leftover centrifugal force that was perceived by the equilibrioception system as being perfectly natural, which proved to cure the effect.

This also led to a further embarrassing discovery. The work that suggested the amount of tilt needed to reduce the lateral forces to acceptable levels was eventually traced to a short series of studies carried out by a steam train on a branch line in northern Wales in 1949. A series of updated studies carried out in 1983 demonstrated less tilt was needed, about six degrees. This was within the range possible through superelevation, which suggested tilting might not be needed at all.<ref name=flop/>