General Information on Track Circuits - RGS Online

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<strong>General</strong> <strong>Information</strong> on Track Circuits
Railway Group Approved Code of Practice
GK/RC0752
Issue Two
Date December 1998
Page D11 of 20
individual pieces of rail which are bonded together with fishplate bonding. There
are four types of jumper bonding:
Standard Jumper Bonding
A jumper bond between sections of rail which is proved intact as part of fail–safe
series bonding and does not form any part of a traction current system.
It is a light current cable installed by the Signal Engineer.
Yellow Standard Bonding
Used on non–electrified lines or long spurs of insulated (signal) rail on electrified
lines.
A jumper bond between sections of rail which is not proved intact by fail–safe
series bonding. Safety is assured by installing at least three alternative jumpers,
such that two jumper disconnections are not, by themselves, unsafe. It is a
mechanically robust light current cable installed by the Signal Engineer and
identified either by a yellow sheath or a yellow sleeve at its termination. Its
mechanical strength allows its electrical integrity to be inferred from regular visual
inspection.
Traction Jumper Bonding
Traction rated bonding attached to the traction rail of electrified lines but which is
not relied upon for the integrity of track circuit operation.
Yellow Traction Bonding
Provided in accordance with the same design principles as Yellow Standard
Bonding, except that it is traction current rated.
It is installed by the Electric Traction Engineer (except impedance bond end
connections which are connected by the Signal Engineer).
13.2 Design Principles for Yellow Bonding
The design principles whereby the need for yellow bonding is identified are the
same for both non–electrified and electrified lines. Electrification only affects the
rating of bond to be installed and the organisation responsible for its installation
and subsequent maintenance.
Yellow bonding shall ensure that a single or double disconnection will not result
in an unsafe condition. See GK/RT 0252.
13.2.1 Yellow Bonding
Where separate sections of rail are required to be electrically interconnected in
parallel, each section is to be bonded to the adjacent section at each point of
abutment using a yellow bond.
Each spur extremity is to be bonded to another part of the same electrically
common network, which is not itself a part of the same spur, using a yellow
bond.
In addition to any switch reinforcement yellow bond, each section must have at
least three yellow bonds attached to it in different physical locations, which
should be a minimum of 20m apart. Additional yellow bonds are to be installed
to achieve this and, wherever possible, the additional bonds must connect to a
different section from those already fitted.
In the case of non–electrified multiple track plain line, the common rails of parallel
tracks must be cross bonded together using yellow bonds at the site of
feed/relay ends and at least 1km intervals.
Yellow bonds are to be clearly identified on bonding plans as shown in Part C.
RAILTRACK D11