Network Rail

AC Electrified Lines Traction Bonding – Requirements for Signal Engineering Involvement and Track Circuit Testing
 N TI 172 ISSUE 1

Annotation

This instruction applies to traction bonding arrangements on a.c. electrified lines where train detection is provided by

-

d.c. track circuits

-

HVI track circuits

-

Audio frequency track circuits (e.g.TI21 or EBITrack)

-

axle counters

-

Reed track circuits

For the purposes of this instruction, traction (i.e. “Non-Signalling”) bonds include:

-

structure to rail bonds

-

traction rail to rail bonds

-

impedance bond centre plate connections (on all types of track circuits employing impedance bonds).

-

OLE along track conductors, including earth wires, return conductors and associated connections to traction rails

-

Return screening conductors and associated connections to traction rails