Leaves On The Railway Line

It's that time of year again. Everyone has heard the apologies for delays due to "leaves on the line" - but what does that mean?  How can a small thing like leaves affect a big heavy train.

How leaves on the line affect train services

The leaf fall in autumn often causes poor rail head conditions and can affect train performance and punctuality in a number of ways.

When leaves fall on to the line, particularly in damp or wet weather, 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 between wheel and rail - hence the phrase "low rail adhesion".  The leaf mulch can also affect the operation of track circuits, which is a key element of train signalling. The contamination is very difficult to remove from both wheels and rails and is often compared to Teflon, being very difficult to remove and very slippery.

In order to comply with safety requirements Train Drivers adopt defensive driving techniques. This includes reducing speed to prevent slipping or over running platforms or signals, and as braking can be affected, braking distances are extended.

If you’re a regular rail traveller, you can probably sense the wheel “slipping” on a train if you’re travelling through an affected area. This is usually why delays are more prevalent at this time of year, particularly in the early morning and early evening.

See how BBC's Bang Goes The Theory demonstrated the effect.

How we tackle low rail adhesion

Iarnród Éireann have adopted proactive and reactionary measures to reduce the adverse impact LRA can have on Safety and Performance:

• Vegetation Management: Managing trees and other vegetation, in line with environmental and biodiversity controls, such as avoiding bird nesting periods.  New drone technology is used to identify at risk trees. €9.6m was invested in 2024 to cover tree felling and vegetation control across the three CCE divisions.
• Specialised Water-Jetting and Gel Application Machine: A Multi-Purpose Vehicle (MPV 790) operates late at night Monday to Saturday in the Dublin Commuter area to clean the track before the early morning peak, covering 70 shifts. It first clears fallen leaves and contamination by cleaning the railhead with a high powered water jet at the front of the train and then applying a special ‘gel’ substance to the rail. The specially formulated gel consists of sand, antifreeze and steel shot that improves adhesion between train wheels and the railhead.
• Traction Gel Applicators (TGAs): 127 solar powered TGAs are installed across the network in known LRA hotspots. When a train passes over the unit, it dispenses traction gel which improves the grip between the wheel and rail interface. The gel dispenser is topped up before the LRA season and is regularly checked. 5 new TGAs have been commissioned for the 2025 season at Woodbrook, Glenageary, Kilcoole & Ballyhale.
  
• Manual Gel Application and LeafGuard: Hand held gel applicators & specialised rail-head scrubbers are positioned at strategic locations, near junctions etc. and are utilised by specially trained maintenance staff in order to provide a rapid response when necessary. Increased use of Interflon LeafGuard OTR, a biodegradable railhead cleaner which improves wheel traction for up to 7 days. It showed up to 70% LRA improvement on 2024 DART & Maynooth test sites with further improvements in application being tested for 2025 in Limerick Jctn. and Athlone divisions.
  
• On-Board Sanding Equipment: All IÉ passenger rolling stock and 201 class locos are equipped with on board sanding systems which dispense sand when wheel slip is detected.  Drivers can also manually dispense sand when required.  Sand boxes are regularly checked during the LRA season. Sanding was added to Enterprise carriages during 2024 (2 sand boxes per set). CME issue Knowledge bulletins briefings to staff on sanding importance & awareness of differences between different fleet types.
• Data Collection: A dedicated team of people continuously work on ways of tackling the issues LRA present.  Continuous monitoring and recording forms the basis of a valuable database to allow IÉ focus on specific LRA contributory elements, such as known hotspots.  Weather and Leaf fall rates are also captured. In 2024, 40,000 delay minutes were caused by LRA conditions, compared to 26,000 minutes in 2023.
• Frontline Staff: Colleagues from CCE, CME, SET and Ops work to ensure our rail system operates safely in these conditions. SET have upgraded train detections and track timer installations.
• Competent Drivers: In order to comply with safety requirements Train Drivers adopt defensive driving techniques.  This includes reducing speed to prevent slipping or over running platforms or signals as well as carrying out frequent running brake tests.  As braking can be affected, braking distances are extended. All Drivers are briefed before the LRA season commences on the risks they’ll experience through the provision of handbooks and posters.
• LRA Risk Forecast: From late September to early December, a 5 day risk forecast is issued advising all staff if the risk of an LRA event is:
  • Low (Green)
  • Moderate (Yellow)
  • High (Red) or
  • Severe (Black)

This allows all colleagues to prepare and anticipate LRA occurring.

• LRA Timetable – NEW for 2025: A LRA Timetable will commence from mid-September and end on 12th December ahead of the new Timetable on 14th December.  Timetable adjustments will add over 2,600 additional runtime minutes per week in the greater Dublin area.  Where possible morning peak times are advanced by 3 to 5 mins and evening peaks have additional runtime.
• Best Practice: LRA affects many countries with a temperate climate and IÉ are a member of a group consisting of UK Train Operating Companies, which meet on a regular basis to tackle the problem.
• Customer Impact: Customer queries can be directed to this website, which highlights the issues and actions to limit its impact. This will be complimented shortly by a news story, regular tweets and a “Leafometer” when we enter the peak LRA season.

Michael Danaher our Infrastructure Manager in the East Region tells us more:

The number of weeks this can continue for varies from year to year, depending on weather conditions. However, we will continue to work throughout the period affected to minimise delays on services, and apologise for the inconvenience caused.

For daily updates on service impacts from low rail adhesion and for the latest service information and news from Iarnród Éireann, follow us on Twitter. 

Check out our Autumn Leafometer for how many leaves are left on the trees which we will keep updated throughout the season;