Northern line has recently been upgraded to the new CBTC Signalling system can you provide me information on all the new wayside signage that has been installed and tell what purpose each type of sign servers for the driver. (for each sign please provide a picture) There is also a sign which is not signalling related it is located at east finchley station it is a rectangular board on which the word "PTI RESET" is inscribed what is the purpose of this sign. At edgware station on all platforms there is a new type CBTC signal that on occasion illuminates with acronym of a station when the train is ready to depart what is the purpose of this new signal if everything is controlled on board the train and is it always in operation? The London underground signalling department should hold all the above information.

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TfL Ref: FOI-2279-1920

Thank you for your request received by Transport for London (TfL) on 29^th October 2019 asking for information about signalling on the Northern line.

Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy.

Specifically you ask:

“Northern line has recently been upgraded to the new CBTC Signalling system can you provide me information on all the new wayside signage that has been installed and tell what purpose each type of sign servers for the driver. (for each sign please provide a picture)

There is also a sign which is not signalling related it is located at east finchley station it is a rectangular board on which the word "PTI RESET" is inscribed what is the purpose of this sign.

At edgware station on all platforms there is a new type CBTC signal that on occasion illuminates with acronym of a station when the train is ready to depart what is the purpose of this new signal if everything is controlled on board the train and is it always in operation?”

I can confirm that we hold the information you require. However, the information is exempt from disclosure under sections 24 (National Security) and 38 (Health and Safety) of the FOI Act. In this instance the exemptions have been applied as disclosure of the information you have requested could assist any persons wishing to disrupt London’s transport infrastructure by placing into the public domain information which would otherwise not be available via other means. Whilst we make no suggestion that you would use this information for anything other than you own interest, disclosure of information under FOI has to be regarded as a disclosure to the public at large.  As you will no doubt be aware, the transport system in London has been the target of terrorist attacks in the past. The information you seek details information about the operation of the network which could be of use for anyone seeking to research or plan for such an attack or to cause disruption to the network.

The Information Commissioner’s Office has previously issued a Decision Notice regarding the application of sections 24 and 38 to withhold information in relation to security at transport hubs. Whilst the information requested in this case is different to the information you have requested we believe the same arguments can be applied:

https://ico.org.uk/media/action-weve-taken/decision-notices/2017/2013536/fs50633090.pdf

The use of the section 24 and 38 exemptions are 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, and acknowledge that there may be some public interest in the information in question. However, as we believe this information could potentially be obtained and utilised by individuals who may wish to use it to cause disruption or harm to London’s transport infrastructure, in this instance we believe that minimising the risk to that infrastructure and protecting the safety and welfare of members of the general public and our staff outweighs the public interest in disclosure.

Please see the attached information sheet for details of your right to appeal.

Yours sincerely,

David Wells

FOI Case Officer

FOI Case Management Team

General Counsel

Transport for London

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