FOI request detail

Reliability of TfL's rail network (Underground, Overground, Elizabeth line, and DLR)

Request ID: FOI-2066-2223
Date published: 29 December 2022

You asked

I've come from Singapore whose "MRT" is renowned for the improvements that it has made in terms of it's reliability, and I have recently moved to London and started using the Underground, Overground, Elizabeth line and DLR for commuting. It felt to me that delays were much more frequent on TfL's rail network, which is why I sought information to know what is the reliability of TfL's rail network using a specific measure called Mean Kilometres Between Failure (MKBF) which is a measure of reliability used by train operators around the world, where a failure is defined as a service delay of more than five minutes, and train kilometres are used. I did manage to find an outdated FOI request (TfL Ref: FOI-3074-1819) with a metric called Mean Distance Between Failures (MDBF) and I have a few questions about this. How is a failure defined in MDBF? Is it a service delay of more than 5 minutes as well? Additionally, the data provided in the FOI request made in March 2019 mentioned only covers MDBF until 2018, so have there been any updated figures for each of the types of TFL rail and lines that I have mentioned? Also in 2017, Singapore used to have a train line (North-South Line) with a MKBF of 89,000 km [1], but has managed to improve to 894,000 km in 2018, and the SIngaporean MRT network now has lines with over 1,000,000 km of MKBF [2], yet TfL's network is languishing at below 100,000 km of MDBF, so has there been any steps taken to close the gap with the MRT? I feel that London deserves a world class reliable train system for commuting, but it falls short. Please do include this statistic in any future reports where performance is mentioned such as TfL's annual report so that people can see how much traveling is done by trains before a problem arises, and gauge where London's public transit ranks in the world. References: [1] [2]

We answered

Our ref: FOI-2066-2223/GH
Thank you for your request received by Transport for London (TfL) on 19 November 2022 asking for information about the reliability of TfL's rail network, and for your clarification.

Your request has been considered under the requirements of the Freedom of Information Act 2000 and our information access policy. I can confirm that we do hold some of the information you require.

Please see the attached spreadsheet which provides information for London Underground. On an annual basis we collate all delays of 5 minutes or more and this is included here.

The Fleet MDBF definition is based on the current London Underground scorecard definition.  Note this is different to the definition that would have been used in the previous FOI that you referenced.

Note the format of the data for the two methodologies is different based on the existing reporting needs. 

This performance measure is not recorded for other services – the normal measure used by TfL is a service delay in excess of 5 minutes.

For Rail public measure can all be found on the ORR website…

If you are not satisfied with this response please see the attached information sheet for details of your right to appeal.

Yours sincerely

Graham Hurt

FOI Case Officer
FOI Case Management Team
General Counsel
Transport for London


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