According to reports in the press, there was a wrong-side signalling incident on Saturday 14th October on the Piccadilly and District Lines in the vicinity of Barons Court, involving a defect in the Surface Stock Detector tubes and a signal not being returned to danger when it should have been. Please provide copies of any reports or investigations into this incident and plans by TfL to ensure there is no repeat of any such wrong-side failure.

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Our ref: FOI-2560-1718

Thank you for your email received on 6 December 2017 asking for information about a signalling incident near Barons Court on 14th October 2017. I apologise for the delay in replying to you.

Your request has been processed in accordance with the requirements of the Freedom of Information Act and our information access policy. You asked:

According to reports in the press, there was a wrong-side signalling incident on Saturday 14th October on the Piccadilly and District Lines in the vicinity of Barons Court, involving a defect in the Surface Stock Detector tubes and a signal not being returned to danger when it should have been.

Please provide copies of any reports or investigations into this incident and plans by TfL to ensure there is no repeat of any such wrong-side failure.

Please find attached the Daily Performance Report which covers the incident at the time. Additionally the photographs below are the key aspect of the findings. Prevention plans for similar future incidents are still being prepared, however we have checked all similar types of relays on the system to ensure they are in good condition.

The investigation team found that the left hand spindle pivot pin was contaminated with what appears to be the build up of verdigris which was also present in the right hand jewel bearing. Whilst not conclusive it is likely that the presence of this matter prevented the relay from releasing. Arrangements have been made for the spindle and jewels to be sent to a specialist test house for scientific analysis, which help the investigation to reach firm conclusions.

Please note that names, email addresses and telephone numbers have been redacted from the report. This is done in accordance with TfL’s obligations under the Data Protection Act 1998 (DPA), as required by section 40(2) of the FOI Act. This is because disclosure of this personal data would be a breach of the DPA, specifically the first principle of the DPA which requires all processing of personal data to be fair and lawful. It would not be fair to disclose this personal information when the individuals have no expectation it would be disclosed and TfL has not satisfied one of the conditions of Schedule 2 of the Data Protection Act which would make the processing ‘fair’. This exemption to the right of access to information is an absolute exemption and not subject to an assessment of whether the public interest favours use of the exemption.

If this is not the information you are looking for, please feel free to contact me.

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

Yours sincerely,

Melissa Nichols

FOI Case Officer

FOI Case Management Team

General Counsel

Transport for London

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