1) What was the reason behind the decommissioning of the platform emergency plungers along the Jubilee line? 2) Do you have a record of how many times these plungers were activated prior to their decommissioning? 3) Have alternative options been considered? 4) How much money is being saved by no longer maintaining the system? I also have the exact same 4 questions for the tunnel telephone wiring. I am referring to the two wires that go down the tunnels, which train operators could pinch and rub together to discharge traction current, or connect a telephone to each wire to talk to the controller or other appropriate person. 1) What was the reason behind the decommissioning of the tunnel telephone/tunnel emergency wiring along the Jubilee line? 2) Do you have a record of how many times these wires were activated prior to their decommissioning? 3) Have alternative options been considered? 4) How much money is being saved by no longer maintaining the system?

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TfL Ref: FOI-2700-1819

Thank you for your email received on 14^th January 2019 asking for information about the use of emergency plungers and telephone wiring on the Underground

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 some of the information you require. Your request was in two parts, which are addressed in turn below. Firstly, you asked:

“1) What was the reason behind the decommissioning of the platform emergency plungers along the Jubilee line?

2) Do you have a record of how many times these plungers were activated prior to their decommissioning?

3) Have alternative options been considered?

4) How much money is being saved by no longer maintaining the system?”.

Emergency plungers on the Jubilee line were never ultimately commissioned. While the plungers themselves were installed they were not wired into the signalling system, as before they went live TfL risk-assessed their requirement and determined that they were not needed. Given the plungers were not commissioned, we are unable to answer your questions above.

You then asked:

“I also have the exact same 4 questions for the tunnel telephone wiring. I am referring to the two wires that go down the tunnels, which train operators could pinch and rub together to discharge traction current, or connect a telephone to each wire to talk to the controller or other appropriate person.

1) What was the reason behind the decommissioning of the tunnel telephone/tunnel emergency wiring along the Jubilee line?

2) Do you have a record of how many times these wires were activated prior to their decommissioning?

3) Have alternative options been considered?

4) How much money is being saved by no longer maintaining the system?”.

These questions are answered in turn as follows:

Question 1: The main functionality of the tunnel telephone wiring was to discharge traction current in the event of an emergency. Its secondary function was a communications link to the controller. Both of these functions can now be carried out using the connect radio system instead.

Question 2: There is no comprehensive record of how many times these wires have been used in the past – note that the system was first introduced on the Underground network in the 1930s; it was then updated in the 1960s and again in the 1970s. That said, our records show that there has been no use of the tunnel telephone wires to discharge traction current or to communicate with service control since 2013, and the last time such functionality was used is likely to have been long before that.

Question 3: As mentioned above in the answer to question 1, the alternative option is the connect radio system.

Question 4: The resources used to maintain the tunnel wires will be utilised instead to run the solid core replacement cabling, so there is no cost savings as a result. There will, however, be a benefit to customers due to the reduction in delays caused by wire breakages.

If this is not the information you are looking for 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,

David Wells

FOI Case Officer

FOI Case Management Team

General Counsel          

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