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 E49 of 52
Figure E51 gives details of Orange Group Cables (For Pin Drive Connections).
Note Orange Group cables are shown for reference only – preferred rail
connection is by 12mm dia. stud (pin brazed or Cembre).
Item Cable Connection Orange Label Legend Catalogue
No
Length
(mm)
Lug
Types
1 P3 Bond to Rail Top P3 to Pin Drive Top 88/29477 765 B & H
2 P3 Bond to Rail Bottom P3 to Pin Drive Bottom 88/29476 715 B & H
3 Busbar to Rail Long Busbar to Pin Drive Long N/A 1070 C & A
4 Busbar to Rail Short Busbar to Pin Drive Short N/A 690 C & A
5 M Bond to Rail Top M to Pin Drive Top 88/29475 765 D & D
6 M Bond to Rail Bottom M to Pin Drive Bottom 88/29474 715 D & D
7 M2, 5 & 6 Bond to Rail Top M2, 5, 6 to Pin Drive Top 88/29473 685 D & A
8 M2, 5 & 6 Bond to Rail Bottom M2, 5, 6 to Pin Drive Bottom 88/29472 660 D & A
9 B Bond to Rail Top B to Pin Drive Top 88/29471 690 F & A
10 B Bond to Rail Bottom B to Pin Drive Bottom 88/29470 690 F & A
11 DE Bond to Rail DE to Pin Drive 88/29469 765 C & A
12 DD Bond to Rail DD to Pin Drive 88/29468 485 C & A
13 S or MR Bond to Rail S or MR to Pin Drive 88/29467 740 G & A
14 Busbar to Pin Drive Busbar to Pin Drive 88/27723 800 G & H
Figure E51
18.2 Side Lead Connection
In order to minimise imbalance of traction return current in the impedance bond
traction coil, every attempt should be made to ensure electrical balance of the
two sets of rail to impedance bond connections. Only aluminium conductors
should be used. Copper and aluminium side leads should not be mixed on the
same impedance bond as they have different characteristics and the bond will
become unbalanced.
When a Type 3 impedance bond is used at a site requiring only two side leads
these should be connected to the impedance bond lugs using the two holes
nearest to the impedance bond casing. At all sites where the impedance bond
lugs are at different heights, the side lead connections to the higher lug must be
fixed to the underside of the lug.
If only the side leads on one side of the impedance bond are renewed, the
balance should be checked afterwards, as the new ones may have been
installed with a high resistance or the existing leads on the other side may not be
as good as the new ones.
Before any connections are made to the aluminium plate, any burrs or
protrusions should be removed from the mating surfaces of the plate, lug,
washers and nuts. A wire brush or steel wool should then be used to make
these surfaces clean and bright.
R A I L T R A C K E 49