TfL Ref: 1999-1920

Thank you for your request received by us on 3 October 2019 asking for information about London Underground service updates.

Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy. I can confirm that we hold the information you require. You asked for:

the objective criteria used to determine when a tube line is categorised as having "Minor Delays" and which objective criteria are used to define "Severe Delays" and also, how quickly after the actual change of status of a tube line is the TFL Status Board updated online?

Please find attached the current version of the Service Status matrix; the guide we use when declaring the status of services for London Underground lines.

Once the status has been decided, the Network Information Manager enters the details in our system and this is displayed on Electronic Service Update Boards across the London Underground network and on the Transport for London (TfL) website within 60 seconds. The system refresh rate for each is 60 seconds, therefore it may seem that an update appears more quickly if we save the message half way through the cycle, for example.

If this is not the information you are looking for, or if you are unable to access it for any reason, please do not hesitate to contact me.

Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.

Yours sincerely

Jasmine Howard
FOI Case Officer
Information Governance
Transport For London

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