Performance data for Chesham branch of the Metropolitan line
Request ID: FOI-1591-2122 Date published: 11 November 2021
You asked
Please send me a copy of the data tfl use to assess the performance of the Metropolitan line's Chesham branch.
Please also send the nearest equivalent data for the Metropolitan line as a whole and for the Jubilee line.
Please also send me the data used to define whether a delay on the Metropolitan or Jubilee lines is classified as severe or minor.
Data used in the last two reviews? If that doesn’t work for the data tfl hold, data from 1st August to most recent available.
We answered
Our Ref: FOI-1591-2122
Thank you for your request received on 21 October 2021 asking for information performance data for the Chesham branch of the Metropolitan Line.
Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy. I can confirm we hold some of the information you require.
When a train is cancelled or withdrawn, we only record where it was located when it was withdrawn or cancelled – for example in the depot. The recorded information does not tell us if it was a Chesham train or not. Similarly when we record disruptions on the network we record where the disruption occurred such as Harrow on the Hill, as opposed to the locations that may have been impacted as a consequence – such as Chesham.
The data feed for Chesham is unfortunately unreliable and we hope to resolve this problem in the future when the signalling is upgraded. We are able to provide data for Chalfont & Latimer and have attached this, please refer to the “Notes” tab around the limitations of the data.
General reliability statistics for all London Underground lines are published and regularly updated on our website. The main reliability measured currently used are Percentage of Service Operated and Kilometres Operated. Data and definitions for both are available here: https://tfl.gov.uk/corporate/publications-and-reports/underground-services-performance.
If this is not the information you are looking for, or if you are unable to access it for some reason, please feel free to contact me.
Please see the attached information sheet for details of your right to appeal.
Yours sincerely
Gemma Jacob Senior FOI Case Officer FOI Case Management Team General Counsel Transport for London
