[ThomasJ]

http://www.irishrail.ie/news_centre/...ew&news_id=947

Current delays to services due to low rail adhesion by Corporate Communications


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Low rail adhesion, poor rail conditions, wheel slip, poor weather conditions, or even the dreaded “leaves on the line”. There are different ways of describing it, but the seasonal problem causing delays to services in recent weeks is a familiar foe at this time of year.

It’s something this and every other railway has to face, and as the railway’s least favourite ‘season’ is underway, we want to explain to customers how exactly ‘a few leaves’ can cause tonnes of train to be delayed.

When leaves fall on to the line, particularly in wet or damp conditions, the rolling action of passing wheels compresses them, causing a greasy ‘mulch’ to cover the rail. This mulch is to rails what ice is to roads. It reduces the adhesion, or ‘co-efficient of friction’ to use the technical term, between wheel and rail.

If you’re travelling on a train that is covered in this greasy substance, you’ll feel the effect. Acceleration must be reduced to prevent the wheels "slipping", and braking distances extended. This causes delays. The leaf mulch can also affect the operation of track circuits.

Iarnród Éireann has machinery to address this problem, which spreads “Sandite” across the busiest and worst affected lines.

On a nightly basis at the moment, we drive the Sandite machinery across DART and Commuter lines around Dublin, as well as daytime operation between Thurles and Farranfore, and other problem areas as required.

This work can only reduce the impact of leaf mulch rather than eliminate it. The mulch is Teflon-like, and even hand-scrubbing could not remove it.

As you’ll have noticed, this year these conditions are having a particularly bad and ongoing effect on services. Regular minor delays at best are being experienced. The mild, damp and relatively calm conditions have not helped. However, we do expect delays to ease as the leaf fall concludes.

We apologise for the delays caused, and thank you for your patience, and we will continue to work to minimise the effect.