Traction Current Flashcards
What categories are London Underground track divided into?
Line Clear - Tunnel Sections
Line Safe - Open Sections
Depots
When requesting traction current be switched off what details must you give?
Who you are
Where you are
Why traction current needs to be turned off
ALWAYS GET CONFIRMATION TRACTION CURRENT IS OFF.
Who is the responsible person in regards to traction current being switched off
The person who requested the switch off
What is a line clear, line safe message?
A confirmation to the Power Control Room that all staff and equipment are away from the track and it is safe to run trains
Who is responsible for making sure traction current is switched off at the published or amended times?
The Controller
What is the procedure for switching off traction current at the end of traffic hours?
The Signaller will check all scheduled trains, engineering trains and special trains have cleared the section and inform the power Control room. The PCR operator will then contact the controller who will trip the tunnel telephone circuit for that section confirming with Power Control traction current is off.
What does a T board displayed on a head wall mean?
Tunnel telephone and associated apparatus is defective
How do you operate the Headwall Tunnel telephone?
Lift Handset and depress button for 3 seconds. If no direct contact is available you must contact the controller by other means within 5 mins or the controller will turn current back on.
What equipment is available for directly switching off traction current?
Headwall Tunnel Telephone
Section ahead / section in the rear plungers
Short Circuit Devices
What ways can you communicate with a controller in order to turn traction current off in an emergency?
Radio (handheld or train) using mayday button
Auto Phone - use 9XX emergency number for relevant line
Signal post phone
Network Rail emergency phone - to network rail ECO
Public telephone
A controller must not authorise traction current to be switched back on until?
the responsible person has informed him that all staff and equip are clear of the track and it is safe to do so.
What should a controller do if the tunnel telephone system fails to reset?
Ask the Power Control Room to apply overrides
What is the procedure for switching traction current back on at or after the published switch off time?
The controller must talk to the Track Access Manager
Explain why traction current needs to be restored
Request special line clear/line safe message be passed to the PCRO
The controller will then need to talk to the PCRO and
Tell them traction current needs to be switched back on
Wait for a special line clear/line safe message from TAC
Once special line clear/line safe is received the PCRO will contact the controller who will reset the TT and authorise switch in of traction current.
What are the different types of traction current switches, how are they operated?
Section switch - divides a traction current section
Isolating switch - isolates a bay road, siding or terminal platform
Changeover switch - changes over traction current feed in a section of track
Coupling switches - joins two traction current together.
Switches can be controlled either manually or motorised.
Once a section switch has been operated what additional precautions should you take
You must place a hand lamp displaying a red aspect at the foot of the section switch that has been operated
You must also place a second hand lamp displaying a red aspect in the four foot facing all trains as a warning to stop.
