We’ve all heard about ’Leaves on the line’ and moaned about it, but we look at how they affect rail services and how Network Rail keeps those seasonal delays down.
Potentially one of the more embarrassing excuses given for train delays, but nevertheless a serious seasonal problem that Network Rail has to prevent, or at least aid, so that trains run as smoothly as possible.
In the autumn and early Winter to mid December, “RHTT” or Rail Head Treatment Trains operate in order to get rid of “contamination” on rails. Leaves that fall become pressed onto the railhead creating a slippery film between the wheels and rails.
Drivers have to brake more gently and cannot accelerate as fast with slippery rails, as with driving on icy roads. The reduced performance can cause delays between September and December and some timetables are adjusted by a few minutes to keep punctuality statistics higher.
Network Rail operates with Direct Rail Services and DB Schenker across the country to ensure that Britain’s rail network is performing as well as a dry summer’s day, even in the worst of Autumn’s weather.
With bases from Cornwall to the Highlands, and Anglia to Wales, barely any of the country is left without these pivotal services. They have an intelligent system on board which allows them to spray water at such velocities that leaf matter and “contamination” is eradicated instantly, with sandite being added afterwards to further add grip.
Without these services, train services would have to operate to a greatly amended timetable, or would operate with excessive delays. Recently, it was reported that train punctuality had reduced; this occurs every year, during Autumn, as trains battle to maintain competitive headways despite challenging conditions.
When you consider that the size of the contact patch between a train wheel and the track is the same as a 5p coin, it becomes easier to understand why rails have to be kept clean.
When heavy rain falls, it washes the railhead increasing adhesion. If there is heavy fog or drizzle, then this ‘sits’ on the railhead and in essence ‘lubricates’ it and slipping takes place.
The 0645hrs Charing Cross to Hastings train slid for over three miles over a six minute period out of control on November 8. The incident happened at 0810hrs passing through Stonegate station in Sussex with the brakes applied due to poor rail conditions.
The train passed through the station and a level crossing and ironically it turned out nobody wanted to get off at Stonegate anyway!
While a slide of this duration and distance this is exceptional, it shows how a train weighting maybe 400 tons has the kinetic energy to carry on even if the wheels are locked.
The train was a class 375 No. 375711 four car electrostar unit ten years old.
The Rail Accident Investigation Board announced on November 18 that the RHTT train had worked properly but the weather had largely dissipated the effects of the treatment. The passenger train did not deposit sand as it was meant as its supplies had run out and the driver was unaware of this.
There was also a light drizzle at the time, perfect for poor railhead conditions.
Leaves on the line should not be the butt of the media’s jokes.