Peristaltic pump clears the way for Network Rail

When Network Rail looked for new ways of dealing with autumn leaf fall problems, it turned to Portec Rail Products (UK) to manufacture a trackside traction gel applicator.

When Network Rail looked for new ways of dealing with autumn leaf fall problems, it turned to Portec Rail Products (UK) to manufacture a trackside traction gel applicator that would break down the cellulose film generated from crushed leaves.

Watson-Marlow Bredel peristaltic pumps were specified as part of this project to handle the sand-based gel.

A specialist in supplying rail maintenance equipment, Portec Rail Products was approached by Network Rail to design a trackside applicator that could apply a substance called Sandite on to the head of the rail.

The pump is a critical component of the applicator, and so selecting one that could handle Sandite and the harsh environment was a priority.

Portec Rail Products (UK) carried out trials with a number of pump types, such as impeller pumps.

But these soon clogged, and were unable to cope with the sand slurry that forms part of Sandite.

"Unlike other pumps, the Watson-Marlow 701R pumpheads could handle the fluid without difficulty".

"Traction control is a big issue in the autumn, particularly when braking and accelerating".

"Maintaining grip on the line is especially important when approaching and departing from a station, making total reliability from all components in the applicator essential", comments Chris Twigg, Manager at Portec Rail Products (UK).

Previously, crushed leaf deposits on Network Rail's lines had been dealt with by a special Sandite train.

This would travel the length of the track, depositing the abrasive gel in known areas of low rail adhesion.

On busy lines the effect of the Sandite on the track is lost after a number of trains have passed over it.

Using a trackside applicator, Sandite can be applied each time a train approaches.

The trackside applicator consists of a cabinet located 5-6m away from the line, which is linked to an induction wheel sensor attached to the track.

The sensor recognises an approaching train, and signals a controller in the cabinet to actuate the 701R peristaltic pump.

The 701R pumphead draws Sandite from an integral storage hopper in the cabinet and pumps it to spreaders clamped onto the field side of each railhead.

The gel then flows out of the spreader's 6mm holes onto the railhead to form a pool of Sandite that is transferred by the train wheels down the track.

The Sandite combined with the pressure of the wheels breaks down the leaf material.

When asked why Network Rail had specified the use of Watson-Marlow pumpheads, Andy Scobie, Weather Strategy Manager, said: "We had previously used them on a similar application, and having experienced such good results we chose to use them again".

Although the trackside gel application units are only used for ten weeks of the year, they play a vital role in keeping the countries trains running on time.

Located in leafy areas and places with a history of low rail adhesion, they provide a simple solution to the familiar problem of delays associated with leaves on the track.

The Watson Marlow 701R pumphead has driven rollers to provide smooth, low pulse flows up to 2kl/h at 360rev/min, and can accept tubes in five different sizes and seven materials to cope with a wide range of fluids.

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