Low Adhesion Issues Slip Away with New Sanders
Sanders are routinely used on trains to reduce the impact of slippery rail head conditions by blasting sand between the wheel and the rail. RSSB undertook research to find out how the rail industry can optimise the use of sanders. A three-month programme of full scale testing at the Rail Innovation and Development Centre at Melton Mowbray, using two new Class 387 trains loaned by Great Western Railway, generated a robust dataset from over 220 test runs covering various configurations of sanders, test speed and train formation.
This research has proven that changing the approach to sanding by introducing double variable rate sanders, which automatically apply more sand when braking at higher speeds, dramatically reduces braking distances and provides assured 6%g braking performance, which is the basis for timetable planning. In particular, double variable rate sanders can improve stopping distances on a 4-car train by around 50% compared to a single fixed-rate sander.
These are game changing findings because they demonstrate how existing technology can be deployed more effectively to overcome the ‘leaves on the line’ problem and year-round delays caused by poor adhesion. Moving to double variable sanders will reduce delays, platform overruns and signals passed at danger due to low adhesion conditions. Also, by improving the consistency and predictability of train braking, this will be a key enabler to delivering increased capacity.
Two dedicated briefing events (6 February in London and 7 February in Birmingham) brought industry together discuss the findings and explore opportunities and barriers to adopt the new recommended sanding configuration from Autumn 2018.