<p>In 1992 Brecknell Willis supplied 368 top running pneumatically operated retractable third rail collector shoes to Brush Traction for use on British Rail Class 92 freight locomotives (12 per loco). The sparks and arcing seen here are caused by ice deposited on top of the third rail as frost being vapourised between the collector shoe and third rail. Damage can occur to both the retractable collector shoe and conductor rail at the interface when arcing occurs. Class 92s are high power locomotives so prone to arcing. For this reason the microprocessors are programed to detect arcing from the shoes in the leading bogie so automatically cuts back power to reduce arcing in the trailing bogie when it reaches the same point.
</p><p>To reduce the risk of breaking down in the Channel Tunnel class 92s were designed with the aim of duplicating each system where possible, each bogie and its drive working independently of the other. Three sets of retractable shoegear are attached to the side of each bogie (6 per side) but due to the greater need to avoid gapping (loss of contact with the third rail and so loss of power where gaps occur) the distance between contact shoes is maximised by relaxing the requirement for independent systems. Instead the inner most collector shoe on the trailing bogie is cross-connected to the two outer most collector shoes on the leading bogie and vice versa.
</p><p>According to Realtime Trains the route and timings were;
Dollands Moor Sidings .......0646.........0652.........6L
Ashford International T.......0700.........0702.........2L
Maidstone East [MDE] 1.......0733 1/2...0722........11E
Otford Junction[XOT]..........0818..........0819...........1L
Swanley [SAY] 1.....................0830.........0828........2E
St Mary Cray Junction.........0835.........0832.........3E
Bickley Junction[XLY]..........0836 1/2..0834........2E
Bromley South [BMS]...........0840.........0838 1/2...1E
Shortlands Junction.............0843.........0842.........1E
Bellingham [BGM].................0846 1/2..0844........2E
Nunhead [NHD] 1..................0855.........0854.........1E
Peckham Rye [PMR].............0859.........0856.........3E
Crofton Road Junction........0901.........0857..........4E
Denmark Hill [DMK] 1...........0902........0858.........4E
Voltaire Road Junction........0906 1/2..0902.........4E
Latchmere Junction.............0911 1/2....0908.........3E
Kensington Olympia 2.........0922........0914 1/2....7E
North Pole Junction.............0925........0918 1/2...6E
Mitre Bridge Junction..........0926 1/2..0921.........5E
Willesden West Londn Jn...0928.........0922........6E
</p>
Wembley Eur Frt Ops Ctr....0939.........0928........11E
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<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/99279135@N05/16154761965/">92042 Dollands Moor to Wembley</a>