Also known as the maximum journey time, this is an area where TfL have been reluctant to publish details in the recent past. However, after a referral and discussion with the Information Commissioner, TfL have now supplied a spreadsheet containing all the information. This is a significant step towards a more transparent attitude to PAYG charging. Thanks must be noted to Alan, a forum user, who made this recent request and followed it all the way through.
I have used the spreadsheet supplied to add a new panel to the fare finder results page on this site. It’s the purple section after the fares for every route combination have been displayed. There is only one set of times allowed, which apply whichever route is chosen. Each set comprises a base time for weekday daytimes, a 10% addition for weekday evenings and Saturdays, and a 20% addition for Sundays and Public Holidays. The latter uplifts are rounded to the next 5 minutes above if necessary.
Within zones 1 to 6 the base time is 60 minutes, plus 10 minutes for every zone used. Duplicated zones are counted twice, so zone 4 to zone 4 via zone 1 is 7 zones. Additional time is allowed for many journeys within zones 1-4 in recognition of the fact that some lengthy journeys can be made. Where a journey starts and/or ends at a dual zoned station the time allowed includes the other (unused) zone. Thus Hatton Cross (5/6) to Hammersmith (2) is charged as a 4 zone journey (2-5) but timed as a 5 zone journey (2-6). It appears that the time allowed for multi route journeys is based on the highest number of zones, so an avoiding zone 1 journey will be allowed the same time as if zone 1 had been used.