Supply of Third Rail Insulators

open to the material, currently polymer but must meet the standard. If SUPPLIER proposes non-polymeric third rail insulators, a modified type test may be proposed for PURCHASER approval.

requirements for supply of third rail insulators and associated components for use in the Strathclyde Partnership for Transport (SPT) Subway.

The insulators shall be suitable for use in the Subway 600V dc traction system and for use in Subway traction system as modified to 750V dc.

The conductor rail system is designed for current collection at all speeds up to 58kph and under certain conditions a limited degree of arcing can occur. The insulators shall withstand resulting transient effects.

The insulators shall withstand the impact, shocks, strains, stresses and vibrations associated with anchored or unanchored conductor rails, which are subjected to longitudinal, vertical and lateral movements.

The insulators shall withstand the effects of short circuits of varying severity as are likely to occur due to the system environment.

Third Rail

Insulators shall accommodate Subway steel third rail and maintain it in orientation with top surface nominally parallel with plane of rail. The steel third rail has an ‘L’ section. There is some variance in third rail cross sectional profile which shall be accommodated.

Support Brackets

Insulators for use in the system shall be suitable for installation on existing support brackets When installed within a support bracket assembly the insulator shall be shaped and dimensioned to achieve:

The insulator shall be designed for minimum withstand voltages of 25kV dc (dry) and 3.5kV dc (wet).

the insulator colour shall be proposed for PURCHASER acceptance and shall not be green, amber or red.

The insulators shall be suitable for use in a sub-surface environment and shall be Low Smoke Zero Halogen (LSZH) type.