General Information on Track Circuits - RGS Online

Railway Group Approved Code of Practice
GK/RC0752
Issue Two
Date December 1998
Page E10 of 52
Withdrawn Document
Uncontrolled When Printed
<strong>General</strong> <strong>Information</strong> on Track Circuits
8.4 Cembre
Cembre is a method by which a copper bush is expanded inside a 22mm hole
drilled into the rail web. A bolt is then passed through the copper bush and is
used to fix a cable lug to the rail. The copper bush should be inserted and
expanded a soon as the hole has been drilled. If this is not possible, the hole
should be given a protective coating of jointing paste at the time of drilling and
thoroughly cleaned, in the same manner a described for pin drive fittings when
the bush is fitted. Refer to clause 8.6
Cembre Parts Catalogue No.
Rail lead installation kit (M12 steel screw with hollow : 86/017025
hex. head, flat steel washer & self locking nut)
Copper bush for 22mm dia. hole : 86/017026
Expansion plunger. Calibrated high tensile steel : 86/017027
Hydraulic tool with hand pump c/w carrying case : 86/017028
Go/No Go gauge for checking 22mm rail hole : 86/017029
To ensure that the drilled hole is the correct size a gauge is used as detailed
below and shown in Figure E6 :
a) Insert the Go/No Go gauge into the hole.
b) The hole may be used only if the green part passes through and the red part
does not.
c) If the red part passes through, redrill a hole in a different position.
d) The inside of existing holes should be thoroughly cleaned and bright.
Red (No GO Column)
GO / No GO Column
Figure E6
Green (No GO Column)
E 10 R A I L T R A C K
22 Dia
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