The technique was developed by a team of researchers led by Professor Roger Lewis from the university’s Department of Mechanical Engineering. It uses dry ice pellets in a stream of high pressure air which freeze the leaves, then as the pellets turn back to gas they are blasted away from the railhead.
“At the moment, railway lines are cleaned using railhead treatment trains, also known as RHTTs, but there is only a limited number of these trains available so they can’t treat the whole of the network,” said Lewis. “RHTTs are expensive to run, so they are mainly used to clean high-traffic, intercity lines, which means many lines are left untreated.”
Lewis added that the current cleaning system used by RHTTs can damage parts of the track, and the system must be switched off when travelling through stations to avoid spraying passengers, resulting in unclean lines within stations and increased risk of rail delays.
First developed by the group in 2015, their method has been tested on railhead treatment trains over the past two years and on passenger trains in early 2020. According to the team, their technique has proven to be ‘significantly more effective’ at removing leaves from the line, preventing delays and improving trains’ braking distances.
The system is lighter, and can clean parts of the railway network where current methods are unable to reach such as branch lines and track close to station platforms. It doesn’t affect nearby railway infrastructure and is also more environmentally friendly due to its use of reclaimed carbon dioxide, researchers said.
Its successful deployment onboard passenger trains in a collaboration with Northern was the first time that passenger trains have been used to clean the track anywhere in the world. This could reduce congestion on the railway, as extra railhead treatment trains wouldn’t need to be added to the network.
Seasonal improvement manager at Northern, Rob Cummings, described leaves on the line as one of the ‘biggest risks to performance’ during October and November.
Further passenger train trials with Northern will now be carried out through the autumn and winter 2021/22, with the system currently going through approval procedures to run on an in-service line. Network Rail’s Performance Innovation Fund is supporting the trials, and the system is expected to be rolled out widely by 2023/24.