London Underground Speed Limits and Signal Information
Request ID: FOI-2639-2122 Date published: 14 March 2022
You asked
As a rail enthusiast, could I please see documents for:
- The speed limits of each section of track on the Underground
- Signal diagrams or other signal-related documents from the Northern and Jubilee lines prior to the implementation of ATO
We answered
TfL Ref: FOI-2639-2122
Thank you for your revised request received by us on 24 February 2022, asking for actual speed limits and signal diagrams on the London Underground.
Your request has been considered under the requirements of the Freedom of Information Act 2000 and our information access policy. I can confirm we do hold the information you require.
However, in accordance with the FOI Act, we are not obliged to supply the speed and signal information you have requested as it is subject to statutory exemptions to the right of access to information, under Section 38(1)(b) and Section 24 of the Act.
In this instance the exemptions have been applied as disclosure of this information would be likely to adversely affect the safety and security of TfL employees and members of the general public as well as national security.
Disclosure of this information to you has to be regarded as a disclosure to ‘the public at large’. This information could potentially be obtained and utilised by individuals who may wish to use this detailed level technical information to cause disruption or harm to the London Underground network. It is our concern that the release of details about the operating environment could be combined with other information already in the public domain to help plan an attack. The signal information provides precise locations of key parts of the network which could be used to gain access to these areas. Disclosure could compromise the security and safety preparedness on the London Underground’s network and disrupt our services by highlighting areas on the network which could be susceptible to being targeted.
Whilst we make no suggestion that you would use the information for anything other than your own personal interest and the use you outlined in your request, the London Underground system is an attractive terrorist target for several reasons including its importance to London and the knock on effect to the nation’s economy if it is disrupted, the publicity gained from attacking an iconic transport system and the attractiveness of the system for a mass casualty attack due to its open, mass transport nature. It is also important to the functioning of London and its economy.
The use of these exemptions is subject to an assessment of the public interest in relation to the disclosure of the information concerned. We recognise the need for openness and transparency by public authorities, but in this instance the public interest in applying the exemption, in order to minimise risks to operational resilience, safe operation of the London Underground network, the welfare of staff and members of the general public, outweighs the public interest in disclosure.
