Leaves on the Line: The Railway's Seasonal Foe

The railway is a marvel of modern engineering, connecting people, businesses, and communities. However, it faces unique challenges with each changing season.

As autumn arrives, so do cooler temperatures, wetter and windier conditions, and falling leaves. While autumn's beauty is undeniable, it poses a significant challenge to railway operations. In this article, we delve into the impacts of autumn on the railway and how the industry works tirelessly to ensure safe and timely services despite the obstacles.

Autumns Grip on the Railway

Autumn is a season of transition, the nights begin to draw in, the air gets crisper, and foliage turns golden. While this change in scenery is appreciated by many, it can significantly impact railway delivery and performance.

One of the most notorious issues that arises during autumn is the problem of fallen leaves. There are millions of trees alongside the railway, and these trees shed thousands of tonnes of leaves every autumn. This seemingly harmless foliage becomes a substantial challenge as it accumulates on the tracks.

The Slippery Challenge

Leaves on the tracks pose a problem beyond mere inconvenience. As they get wet and compact under the weight of passing trains, they form a slippery mulch that sticks to the rails. What's intriguing is that the rails, made of carbon steel, react chemically with the leaf mulch, creating a black contaminant. This leads to what's known as low adhesion, making it challenging for trains to brake and accelerate predictably, much like the black ice of the road.

Leaves on the railhead can create a barrier between the train wheels and track circuits, creating uncertainty about a train's exact location. Train drivers must also exercise extra caution, slowing down earlier for stations and signals.

The low adhesion risk can translate into thousands of delay minutes each year, station overruns, and signals passed at danger. All these factors contribute to increased journey times and regrettably, delays and disruption.

Managing the Autumn Challenge

The industry works hard to maintain safety and punctuality. Planning and preparation for autumn are critical to keeping tracks and fleets in optimal condition. Here's how the industry keeps the network moving.

Vegetation Management: With the potential of large volumes of leaves falling onto the tracks each autumn, maintaining trees and foliage near the railway is a priority. Network Rail routinely inspects and cuts back vegetation close to the track, especially in high-risk areas where vegetation poses a risk to the safe operation of the railway. They also replace vegetation with species that are less prone to dropping leaves on the track and contaminating the railhead. This careful management allows trains to operate safely while protecting and respecting the natural biodiversity and habitats along the railway.

Railhead Treatment: Dedicated leaf-busting trains equipped with high-pressure pumps clean the rails by spraying them with high-pressure water to remove problematic leaf mulch. These specialist trains can also apply a gritty adhesive gel to the railhead to improve wheel grip. Passenger trains also help to improve adhesion by dispensing sand to provide extra grip on the railhead. Using carefully sourced, screened, and cleaned super fine traction sand, a perfect amount is distributed along the railhead. It can be dispensed by a push of a button by the driver, or even by a train’s management system. 

Forecasting and Planning: Accurate seasonal forecasting plays a critical role in strategic planning. By maintaining a vigilant watch on weather patterns, Network Rail receives leaf-fall projections that indicate which areas require the most attention from its leaf-busting trains. This proactive approach helps target efforts and resources, ensuring the smooth and safe running of the railway.

Operations: During autumn train crew may receive additional information and briefings around high-risk routes, operational changes, safety notices and driving techniques ensuring they are equipped with the latest information to carry out their duties safely. In areas with heavy leaf fall, some operators introduce speed restrictions or publish special autumn timetables with adjusted journey timings to allow train drivers to drive more cautiously.

Preparing Rolling Stock: Ensuring good fleet availability and reliability is vital for navigating the challenges of autumn. This includes conducting checks on wheelsets, ensuring wheel slide protection systems are in good working order, proactively planning tyre turning, and maintaining wheel lathes to ensure optimal performance. It is also important to check scrubber blocks and sanding equipment health, establishing a robust sanding regime to ensure that trains have a sufficient supply of sand.

Looking Ahead

Low adhesion is ever present in railway and although it can occur at any time of year, it is particularly severe in autumn. Operators need robust and effective management plans, taking onboard previous lessons learnt to drive continuous improvement. Collaborative cross industry workshops can drive planning, ensuring plans are effective and responsive to the unique challenges of seasonal operations.

As weather patterns continue to change and become increasingly difficult to predict, the rail industry continues to adapt and innovate. From science and modelling that looks at leaf biochemistry, physics of wheel and rail surfaces to train design, sensing and railhead cleaning technologies, ongoing research and development will ensure that the railway remains a symbol of connectivity and progress, no matter the season.