Precautions staff must take
When you are on a section of line which is adjacent to or
passesover Network Rail lines electrified by the 25kV (A.C.)
Overhead Line Equipment (OLE) system, you must always:
•
•
•
•
consider the overhead lines and attachments to be live
at all times and extremely dangerous to life
make sure that you, your clothing and any articles you
are carrying, are at least 2.75 metres from:
- anything attached to or hanging from the OLE
equipment
- any broken or disconnected wire connected to the
OLE
- equipment, whether it is hanging or lying on the
ground
make sure that any articles do not come within 2.75
metres, by:
- carrying long articles horizontally
- keeping paint, water and other liquids well away
from where they might be thrown, fall or splashed
onto OLE
- keeping tools and equipment, including ropes,
wires, tapes and surveying equipment, well clear
of the OLE 
take extra care to make sure you do not come within
the 2.75 metres when you are:
- on a structure of any kind
- standing on a vehicle
Railway Group Standard GE/RT8000 – AC outlines
safe systems of work for ‘Persons Working On or
Near to A.C. Electrified Lines’.
Restrictions
Do not attempt to remove objects of any description from
the OLE equipment.
Do not carry out any work above OLE equipment (e.g.
bridges, embankments and building roofs) unless:
• there is a physical barrier protecting the work area from
the OLE equipment
OR
• the correct isolation and earthing arrangements have
been made by a Network Rail approved person, and
the relevant Network Rail isolation/immunisation
forms have been issued to the controller of site safety
/ protection controller.
You must treat broken or displaced wires and
anything attached to or near to the OLE as live and
dangerous to life.
REMEMBER
• You must wear LU approved high visibility clothing at all
times when you are on or near the track.
• Be aware of the danger from moving trains.
• Obey all safety signs and warnings when you are on or
near the track.
25kV (A.C.) OLE immunisation arrangements
At some locations, LU running rails carry a proportion of
the return current of the Network Rail electrification. At
these locations ‘red bonds’ are used which if disconnected,
might under normaloperating conditions result in either the
bond, or the equipment to which it is attached, rising to a
dangerous voltage.
‘Red bonds’ must only be disturbed by authorised
personnel.
Do not cut a water, gas, air main or other metal pipe, or
metallic sheath in an area where ‘red bonds’ are used, unless
a temporary electrical continuity jumper cable, fitted by an
authorised person, has been connected across the point
where the cut is to be made. The authorised person must
not remove the jumper cable until the pipe/sheath is again
complete.
There are also supplementary bonds fitted at some locations
for metal cased equipment, metal structures and fittings to
prevent dangerous levels of touch voltages occurring. These
bonds arecovered green and yellow and must not be cut or
disturbed by anyone who is not qualified to do so.
If an emergency isolation of 25kV (A.C.) OLE is required, the
request must be made to the relevant LU controller
25kV (A.C.) OLE immunisation bonds locations
Immunisation bonds are found on Network rail lines that run
adjacent to the following LU lines:
Hammersmith and City line:
- Westbourne Park to Paddington (Suburban), both
roads.
Central line:
- Ealing Broadway to Bridge 29, both roads.
- Railtrack bridge which crosses over LU lines at
North Acton.
The above diagram shows an image of overhead line equipment
District line:
- Ealing Broadway, all roads from the platform buffer
stop end to the ends of Nos. 24 and 25 sidings
roads east of the station.
- West end of Earl’s Court station to Kensington
(Olympia).
- Turnham Green to Gunnersbury, both roads.
District and Piccadilly lines:
- Bridge 29 at Hanger Lane Junction.
Metropolitan and Jubilee lines:
- Bridges MR10 and MR10A between West
Hampstead and Kilburn.
Bakerloo line:
- At Queen’s Park.
Rescuing a person from the OLE
When any part of the person’s body is above, or is within
1 metre of the live OLE, you must make sure that the
electricity is switched off before you approach that person.
London Underground
OS No. LF07
You must always make sure that an emergency
isolation has been taken.
If you become involved in rescuing a person after an
emergency isolation has been taken, you may have to come
into contact with the:
•
OLE, or
•
the person touching the OLE.
In either case, you must make sure your hands are
covered with something dry which will not
conduct electricity. This is because a residual
voltage may be present even though the electricity
has been switched off.
Warning signs indicate the areas electrically
‘immunised’ by red and green and yellow bonds.
If you are going into any of these areas, you must
make sure that your manager or supervisor has
fully briefed you on the safety procedure that you
must follow.
Transport for London
25KV (A.C.)
Overhead Line
Equipment (OLE)
When the person is completely below and no part of their
body is nearer than 1 metre to the live OLE, you must make
sure (whenever possible) that an emergency isolation has
been taken.
However, if you become involved in rescuing a person, it
is not essential for the electricity to be switched off if you
are sure that no part of your body, or clothing, or anything
you are holding will come within 1 metre of the live OLE or
anything else which is in contact with it, and the person you
are rescuing is:
•
completely below the live OLE, and
•
not nearer than 1 metre to it.
If you are not sure whether you or the person you
are rescuing is within 1 metre of the live OLE, you
must make sure that an emergency isolation has
been taken.
You must also make sure that, once rescued, the casualty
does not come within 1 metre of the live OLE or anything
which is in contact with it.
Best practice for staff working /
walking near OLE
Operational Standards
Issue 04