Commuter Trains: City Pollution Or Green Transport?

Trains are considered to be a more environmentally friendly mode of transportation than cars or planes. However, the type of train and energy source can significantly impact the level of emissions produced. Electric trains are emission-free, while diesel trains produce harmful pollutants such as nitrogen oxides and particulate matter, which can negatively affect air quality and cause health issues. In cities with high rail usage, such as London, enclosed train stations with diesel trains have been found to exceed recommended emission levels, posing risks to passengers and workers. While some countries are transitioning to cleaner technologies, such as hydrogen fuel cells, others are facing challenges in replacing older diesel locomotives. Overall, the environmental impact of commuter trains depends on various factors, and efforts are being made to reduce emissions and improve air quality in cities.

Electric trains are emission-free, but 20% of Europe's trains run on diesel

Electric trains are emission-free, but diesel trains produce pollution. According to the European Commission, about 20% of Europe's rail traffic is hauled by diesel locomotives, with countries like the UK, Greece, Estonia, Latvia, and Lithuania being highly dependent on diesel traction. Diesel trains emit harmful pollutants, including nitrogen dioxide (NO2) and particulate matter, which can reduce air quality and pose health risks to passengers, workers, and nearby communities.

The use of diesel trains contributes to poor air quality in enclosed railway stations, as evident in a study conducted at London's Paddington Station, which found emission levels exceeding European recommendations. The study by the University of Cambridge and other institutions published in the journal Environmental Research Letters highlighted the potential risk to individuals in train stations due to poor air quality. While electrification of train lines is a step towards reducing emissions, approximately half of Europe's train lines remain non-electrified.

The UK, with only 41% of electrified train tracks, faces challenges in improving air quality within train stations. Public Health England estimates that 29,000 deaths annually in the UK are linked to air pollution, emphasizing the urgency for emission reductions. EU regulatory frameworks, such as the Stage IIIA and IIIB standards, aim to mitigate the environmental impact of diesel train engines. Additionally, initiatives like the Low Carbon Sustainable Rail Transport Challenge strive to decrease emissions further.

To address the issue of polluting diesel trains, some countries are exploring alternative energy sources for rail transport. For example, Germany has introduced hydrogen fuel cell trains, providing a lower environmental footprint than diesel. In the US, there is growing recognition of the pollution caused by freight trains, particularly in communities of color and low-income areas. California has taken a lead role in this matter by passing rules to fund cleaner, zero-emission locomotives and reduce rail idling near residential areas.

While electric trains are emission-free, the continued reliance on diesel trains in Europe and other parts of the world contributes to air pollution and poses health risks. Efforts to electrify train lines, implement stricter regulations, and explore alternative energy sources are underway to reduce emissions and improve air quality, particularly in areas heavily impacted by locomotive pollution.

Diesel trains at London's Paddington Station exceed European emission recommendations

The UK is highly dependent on diesel locomotives, with about 20% of Europe's rail traffic hauled by diesel engines. While rail accounts for only 0.8% of the transport sector's global emissions, diesel trains in enclosed stations emit large quantities of pollutants, threatening the well-being of travellers and workers.

A study by the University of Cambridge, the University of Minnesota, and Minnesota State University Mankato evaluated the air quality in London's Paddington Station, a major hub serving 38 million passengers annually. The study found that peak-time emissions from diesel trains exceeded European recommendations for outdoor air quality and were higher than nearby roadsides on most days.

The study identified elevated levels of pollutants, including particulate matter, nitrogen dioxide (NO2), and sulphur dioxide (SO2), which are linked to lung disease, heart problems, and premature deaths. These emissions reduced the air quality within the station, posing a risk to passengers and workers.

While UK railway stations are not required to comply with EU air quality standards, the study highlights the need for improvement in the railway sector to reduce emissions and improve air quality in enclosed stations. The electrification of train lines and the replacement of old diesel locomotives with newer, more efficient models or electric trains are potential solutions to this issue.

Rail travel is generally cleaner than driving or flying

Rail travel is generally considered a cleaner mode of transport than driving or flying. This is due to several factors, including the energy consumption and emissions associated with each mode of transport.

Firstly, rail transport has a lower energy footprint than trucks and passenger cars. The steel wheels of trains on steel rails have lower resistance to motion than road transportation, resulting in better energy efficiency. Additionally, the formation of individual rail cars into trains contributes to their improved energy and environmental performance. Freight rail, for example, accounts for about one-third of ton-miles but consumes only around 2% of transportation energy in the United States. This equates to freight railroads being able to move a ton of cargo for approximately 479 miles on a single gallon of fuel, which is around 11 times more energy-efficient than trucks.

Secondly, rail transport can be electrified, reducing emissions. While some trains still rely on diesel engines, which produce pollution, electric trains are emission-free at the point of use. In regions with a less greenhouse gas-intensive electricity generation mix, rail systems can benefit from reduced emissions. Additionally, rail companies are exploring less polluting energy options, such as liquefied natural gas and advanced diesel engine technologies, to reduce emissions on non-electrified lines.

Thirdly, investing in trains and public transportation is argued to be crucial for making transportation cleaner. Initiatives like the Green New Deal advocate for expanding high-speed rail to decrease greenhouse gas emissions from transportation. Upgrading existing lines or building new infrastructure for high-speed rail can make rail travel more competitive with other modes of transport in terms of journey times.

However, it is important to acknowledge that rail travel is not without its challenges. In the context of commuter trains and city pollution, enclosed railway stations with diesel trains can pose risks to passengers and workers due to reduced air quality from exhaust emissions. Upgrading or replacing older diesel locomotives with cleaner alternatives can be economically and technically challenging for rail operators. Nevertheless, advancements in technology and infrastructure are being explored to reduce emissions and improve air quality in and around railway systems.

Freight trains emit more carbon pollution than many US states

Trains are a more environmentally friendly mode of transport than cars or planes. Taking a train instead of a car for medium-length distances reduces emissions by 80%, and taking a train instead of a domestic flight reduces emissions by 86%. However, this is only true for electric trains, as pollution produced by trains is caused by the use of diesel engines. Electric trains are emission-free at the point of use.

In the context of freight transportation, freight trains emit more carbon pollution than many US states. Over 13 million people in the US, predominantly people of colour and lower-income individuals, live and work near railyards, rail lines, and ports, and are directly impacted by locomotive pollution. Locomotive exhaust contains pollutants like particulate matter (PM), which can burrow deep into the lungs, and nitrogen oxides, which create a lethal form of air pollution called smog that is directly linked to heart, lung, and cardiovascular disease and asthma.

The problem is exacerbated by the fact that rail companies often "remanufacture" old locomotives, essentially repairing them just enough to keep them running, which has huge health consequences for nearby communities. These trains need to be replaced with clean, zero-emission locomotives. While the US Senate has started holding hearings to address this issue, and states like California have passed rules to fund cleaner locomotives, the industry is pushing back with an aggressive legal strategy.

To address freight train emissions, strategies that target both greenhouse gases and black carbon are necessary. This includes adopting modern engines, low-carbon fuels, and more efficient practices, such as using vehicle space more efficiently or reducing freight demand.

Rail travel is more energy-efficient than road transportation

The energy efficiency of a transportation mode can be calculated by dividing the useful travelled distance of passengers or goods by the total energy put into propulsion means. In this regard, trains are superior to road transport. For example, freight railroads in the US move a ton of cargo for around 479 miles on a gallon of fuel, while trucks only achieve 42 miles per gallon on a ton-mile basis. This makes freight rail around 11 times more energy-efficient than trucks.

In addition to being more energy-efficient, rail travel is also cleaner than road transportation. Rail transport has lower resistance to motion and the convoy formation of individual rail cars into trains improves energy and environmental performance. Data shows that rail has a significantly lower energy footprint than trucks and passenger cars.

However, it is important to note that the environmental benefits of rail travel are diminished when diesel trains are used. In the UK, only 41% of train tracks are electrified, with the remaining trains relying on diesel engines. Diesel trains produce harmful emissions, including nitrogen dioxide (NO2), which can reduce air quality and cause health issues for those exposed.

To improve the energy efficiency and environmental impact of rail travel, electrification of train lines and the adoption of cleaner energy sources are necessary. In the US, California has taken a leading role by passing rules to fund cleaner, zero-emission locomotives and reduce rail idling near residential areas. Despite pushback from rail companies, these initiatives are crucial to decarbonizing the transportation sector and improving air quality for communities affected by locomotive pollution.

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