scope:

This Technical Instruction applies to all installations of standard TPWS transmitter loops (TCL Part No. 604369-02) on concrete slab track formations of the types found on Network Rail Infrastructure prior to January 2003. A definition of concrete slab track is given within section 4.1 below.

The installation of TPWS transmitter loops on novel forms of concrete slab track introduced to Network Rail infrastructure after January 2003 is not included within the scope of this Technical Instruction, and the effects that these track formations can have on the fields radiated from the TPWS Transmitter Loops will have to be assessed.

Special installation measures are also required for the installation of buffer stop mini-loops (TCL Part No. 604369-12) on concrete slab track, which are described within Network Rail TPWS Technical Instruction No. 27.