Railroad Trains: Air Polluters Or Environmentally Friendly?

Trains and the railway system have played a pivotal role in the economic growth of nations. They are a fast, safe, and effective way of transporting passengers and freight across countries and continents. However, the railway system has also contributed to environmental degradation and pollution. The primary sources of pollution are diesel engines, with locomotive exhaust containing pollutants like particulate matter (PM) and nitrogen oxides, which have been linked to serious health issues. While electric trains are emission-free, about 20% of Europe's rail traffic is hauled by diesel locomotives, and in the UK, only 41% of train tracks are electrified. The age of the trains and tracks, as well as the lack of electrification, contribute to poor air quality and health risks for travellers, workers, and communities living near railway infrastructure.

Electric trains vs diesel trains

Trains are considered one of the greenest modes of transportation available. While the entire transport sector contributes about 22% of global emissions, rail only accounts for 0.8% of this. However, the pollution produced by trains, specifically diesel trains, is still a cause for concern, particularly in communities near freight railroad infrastructure, who are disproportionately impacted by locomotive pollution.

In the UK, only 41% of train tracks are electrified, and British rolling stock has a mean age of 18 years, with many trains deployed before EU emissions regulations came into effect. As a result, diesel trains operating in enclosed stations emit large quantities of pollutants, threatening the health and well-being of travellers and workers. Diesel trains emit pollutants such as particulate matter, which can burrow deep into the lungs, and nitrogen oxides, which create smog, which is linked to heart, lung, and cardiovascular disease and asthma.

Electric trains, on the other hand, are emission-free at the point of use and are considered greener than their diesel counterparts. Electrification of railways is an important part of reducing carbon emissions, with electric trains emitting 20-35% less carbon per passenger mile than diesel trains. This benefit is expected to improve as the electricity generation industry reduces its carbon output.

The case for electric trains is further strengthened by the potential for zero-emission, battery-electric propulsion. Studies have shown that a 241-km range can be achieved using a single standard boxcar equipped with a 14-MWh battery and inverter, consuming half the energy of diesel trains. At future battery prices, battery-electric trains can be cost-effective, especially when environmental costs are considered.

While rail companies may face technical and economic challenges in replacing or retrofitting older diesel locomotives, the renewal of the fleet is necessary to achieve emission reduction goals. Governments in the UK and Wales have recognized this, investing in projects to electrify more railways, reduce carbon emissions, and improve air quality.

Locomotive exhaust and health issues

Locomotive exhaust is a major contributor to air pollution and has significant health implications for those exposed to it. Diesel trains emit large quantities of pollutants, including particulate matter (PM), nitrogen oxides, hydrocarbons, and carbon monoxide. These emissions have been linked to a range of health issues, including respiratory problems, cardiovascular disease, and lung cancer.

The impact of locomotive exhaust on human health has been demonstrated in various studies. One study conducted in the greater Copenhagen area, Denmark, found that diesel trains had significantly higher emission rates of PM, UFP, and black carbon compared to electric trains. The high particle concentration in diesel-powered trains has raised concerns about the long-term health effects on train staff and commuters. Another study, which exposed 29 healthy volunteers to diesel exhaust while sitting as passengers in trains, found that combustion-derived air pollutants were considerably higher in the passenger carriages of diesel trains compared to electric trains.

The health effects of locomotive exhaust exposure can be immediate and severe. Philip Kashap, the director of the Huntsville Suzuki School of Music, experienced breathing difficulties due to exhaust fumes from an idling locomotive, which required the use of inhalers. Similarly, a student at the school became ill, and a parent insisted on relocating classes to their home due to the poor air quality caused by the locomotive exhaust.

The issue of locomotive exhaust pollution is particularly prevalent in older trains, some of which have been running since the last century. These "zombie trains" continue to poison communities with their emissions, leading to health issues for those living nearby. The rail industry has been criticized for remanufacturing these old locomotives instead of replacing them with cleaner, zero-emission alternatives.

To address the health issues associated with locomotive exhaust, several measures can be taken. Regular maintenance and proper ventilation can help minimize soot buildup, optimize engine performance, and reduce emissions. Additionally, addressing sensor failures and replacing malfunctioning oxygen sensors can improve engine performance and lower emissions. Replacing old diesel locomotives with electric trains or cleaner, zero-emission alternatives is crucial to mitigating the health impacts of locomotive exhaust.

Rail companies and pollution

In the United States, the rail industry has been criticised for prioritising profits over the health and well-being of communities, especially those of colour and low-income communities, who bear the brunt of pollution from freight trains. The Association of American Railroads has been accused of "remaufacturing" old, polluting locomotives to extend their lifespan, resulting in decades of harmful emissions.

In the UK, the situation is somewhat similar. While railway travel is considered one of the greenest modes of transportation, with rail accounting for only 0.8% of transport emissions between 1990 and 2009, the ageing fleet of trains and lack of electrification contribute to air pollution. Only 41% of train tracks are electrified, and the mean age of British rolling stock is 18 years, with many trains deployed before EU emissions regulations came into force. This results in poor air quality in enclosed stations and poses a risk to the health of travellers and workers.

However, it's important to recognise that efforts are being made to address these issues. In California, for example, the Air Resources Board has passed rules to fund cleaner, zero-emission locomotives and reduce rail idling near homes and schools. In the UK, the government has initiated various programmes to improve air quality, and the newly formed Great British Railways has been tasked with improving the environmental impact of the rail system.

Overall, while rail companies do contribute to air pollution, there is a growing recognition of the need to transition to cleaner, zero-emission technologies and improve the environmental sustainability of the rail industry.

Rail infrastructure and communities

Rail infrastructure has long been integral to the economic prosperity of nations. However, it has also been at some cost to the environment and the health of communities living near rail lines. While railway travel is considered one of the greenest modes of transportation, rail companies' use of diesel engines and the ""remanufacturing" of old locomotives have led to harmful emissions and air pollution.

In the UK, only 41% of train tracks are electrified, and British rolling stock has a mean age of 18 years, with many trains deployed before EU emissions regulations came into effect. As a result, diesel trains operating in enclosed stations emit large quantities of pollutants, threatening the health and wellbeing of travellers and workers. Poor air quality caused by diesel emissions has been linked to serious health issues, including heart, lung, and cardiovascular disease and asthma.

The environmental impact of rail infrastructure is particularly acute in communities of colour and low-income communities, who bear the brunt of pollution from freight train routes. More than 13 million people in the US live and work near railyards and rail lines, suffering from the health consequences of locomotive pollution. In addition to air pollution, rail infrastructure can also cause soil and water contamination due to fuel combustion, track abrasion, and freight leakages.

To address these issues, governments and rail companies are taking steps to improve the environmental sustainability of rail transport. California, for example, has passed rules to fund cleaner locomotives and reduce rail idling near homes and schools. In the UK, the recently announced Great British Railways authority aims to improve the environmental impact of the rail system, including reducing carbon emissions and encouraging biodiversity. While electrification of train lines and the adoption of zero-emission locomotives are key solutions, the renewal of the fleet is a significant challenge, especially for older diesel locomotives.

Railway pollution in the UK

While the UK's railway system is one of the greenest modes of transportation available, it still contributes to air pollution. In this context, the UK faces challenges due to its extensive use of diesel engines, with about 20% of Europe's rail traffic being hauled by diesel locomotives. The UK is highly dependent on diesel traction, with only 41% of train tracks electrified. This reliance on diesel engines is a significant source of pollution, as they emit harmful pollutants such as particulate matter, nitrogen oxides, hydrocarbons, and carbon monoxide.

The impact of railway pollution is particularly concerning in enclosed stations, where diesel trains can emit large quantities of pollutants, posing risks to passengers and staff. A study at London's Paddington Station found that emissions within the station exceeded European recommendations and were higher than those on a nearby busy road. This highlights the potential for significant air quality issues in specific areas, even if rail's overall contribution to national emissions is relatively small.

To address these issues, the UK railway industry has developed strategies to improve air quality. The Rail Safety and Standards Board (RSSB) has published an Air Quality Strategic Framework, which focuses on modelling, mitigating, and monitoring emissions. The industry has also launched the Clean Air Research Programme (CLEAR) to gather data and better understand the impact of rail on air quality. Additionally, the use of active air filtration systems in carriages can help reduce exposure to particulate matter and other airborne pollutants.

While the UK rail industry is taking steps to reduce its environmental impact, there are challenges in replacing or retrofitting older diesel locomotives to meet tighter emission limits. The UK government has implemented legislation to reduce emissions from diesel engines, such as the Stage IIIA and IIIB standards, but it is technically and economically demanding for rail operators to comply with these stricter standards. As a result, the renewal of the fleet with more efficient and environmentally friendly locomotives is being prioritized to achieve emission reduction goals.

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