Trains And Pollution: What's The Real Damage?

Trains are widely considered to be an environmentally friendly mode of transport. However, they still produce pollution, which can affect air quality and public health. Pollution from trains is primarily caused by the use of diesel engines, which emit harmful gases and particles that contribute to air pollution and can lead to health issues such as asthma and lung disease. Electric trains, on the other hand, are emission-free and more environmentally friendly. The construction and operation of railways can also cause soil and water pollution and impact wildlife through noise and vibration. While trains are generally better than planes and cars in terms of emissions, the type of train and the source of electricity used can significantly impact their environmental footprint.

Trains are a more environmentally-friendly mode of transport than cars or planes

Trains are widely considered to be a more environmentally-friendly mode of transport than cars or planes. This is largely due to the fact that trains can carry a larger number of passengers than cars, and emit less CO2 per passenger kilometre than planes. According to Greenpeace, on about a quarter of European routes, train tickets are not only cheaper but also more eco-friendly than plane tickets. For example, travelling by train from Berlin to Prague is not only more cost-effective and time-efficient, but also 30 times more environmentally friendly than flying.

However, the reality is more nuanced than a simple comparison between trains, cars, and planes. The environmental impact of a journey depends on various factors, such as the type of energy consumed (petrol, diesel, or electric) and the number of passengers. For instance, travelling in a fully-packed low-emission or electric vehicle can result in lower emissions per person than travelling by train. Similarly, the type of train ticket matters, with first-class travel often doubling the carbon footprint due to the reduced number of seats.

Additionally, the problem of air pollution is not just about the direct emissions of particulates and gases from fossil fuel combustion, but also how these interact with meteorological conditions and chemicals in the atmosphere to create other pollutants. For example, while reducing emissions from highways and increasing them on railways can lead to a decrease in NO2 and primary PM2.5 near highways, it can also increase EC concentrations near railways.

Nevertheless, trains are becoming increasingly environmentally friendly over time, with the electrification of railway networks and the development of more energy-efficient models. In contrast, the quick renewal rate of cars means that new technology appears on the roads relatively quickly, potentially outpacing the improvements in the train industry. Furthermore, choosing public transportation over driving has broader implications beyond just emissions. It demonstrates a public need for this infrastructure, pushing for greater investment and leading to cities that are safer and more conducive to biodiversity.

Diesel trains emit more than electric trains

Trains are considered an environmentally friendly mode of transport. However, diesel trains emit more pollution than electric trains. Electric trains are emission-free at the point of use, while diesel trains emit large quantities of pollutants, leading to poor air quality.

In the UK, about 41% of train tracks are electrified. The remaining tracks rely on diesel-powered trains, which emit harmful pollutants such as particulate matter, nitrogen oxides, hydrocarbons, and carbon monoxide. 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 highly dependent on diesel traction.

Diesel trains emit nitrogen dioxide (NO2) and particulate matter (PM2.5), which can negatively impact air quality and pose health risks to passengers and workers in enclosed railway stations. An independent study evaluated the air quality at London's Paddington Station, finding that emissions from diesel trains exceeded European recommendations and breached limits for outdoor air quality.

To address this issue, governments are introducing initiatives such as the Intercity Express programme, which includes the deployment of electric and bi-mode trains. Electric trains offer carbon-free journeys and emit 20-35% less carbon than diesel trains. Additionally, train manufacturers are exploring hydrogen technology for propulsion, resulting in zero direct greenhouse gas emissions.

While diesel trains have historically contributed to pollution, advancements in technology and the transition to electric and alternative fuel sources are helping to reduce emissions and improve air quality. These efforts are crucial, especially considering the growing demand for rail transport and the need to provide sufficient rail capacity while minimizing environmental impact.

Trains can cause noise and air pollution in stations

Trains are widely recognised as an environmentally friendly mode of transport. They are more efficient than cars, emitting 80% less greenhouse gases per kilometre, and they can move far more people per hour than a freeway lane. However, trains can cause noise and air pollution in stations, particularly when diesel engines are used.

The main source of train pollution is the use of diesel engines. Electric trains are emission-free at the point of use, but about 20% of Europe’s current rail traffic is hauled by diesel locomotives, with some countries, including the UK, being highly dependent on diesel traction. Diesel trains emit more than twice the carbon of electric trains, and their use in enclosed stations can pose a significant health risk to passengers and workers. A study of London’s Paddington Station found that emissions of nitrogen dioxide during peak times far exceeded European recommendations, and were higher than those on a nearby busy road.

The UK has legislation in place to limit the environmental impact of diesel train engines, and EU standards require diesel engines greater than 130 kW to reduce exhaust emissions. However, it is technically and economically challenging for rail operators to replace older diesel locomotives with more efficient engines. The UK government admits that indoor public health standards for train stations are neither well understood nor controlled by a specific agency, and air quality within stations is poorly documented.

While trains can cause noise and air pollution in stations, particularly with diesel engines, they are still a much more environmentally friendly mode of transport than cars, and electric trains are even better for the environment than diesel trains.

Trains can disturb wildlife and their natural habitats

Trains can have a significant impact on wildlife and their natural habitats. There are four main ways in which trains disturb wildlife: wildlife mortality, the barrier effect, habitat fragmentation/loss, and disturbances.

Firstly, wildlife mortality refers to the risk of animals being killed in collisions with trains. This can directly impact the connectivity and reproductive success of sub-populations. Certain species, such as moose, bear, and deer, are larger and more likely to cause financial impacts when collisions occur. Smaller species, such as birds, mammals, and herpetofauna like the eastern box turtle, are also at risk of being struck by trains or becoming entrapped in the rails.

Secondly, the barrier effect describes how railways can act as physical and behavioural barriers to wildlife movement. They can prevent species from moving freely across the landscape, leading to reduced connectivity and potential isolation of sub-populations. This effect is particularly pronounced for smaller vertebrates, as they are reluctant to cross open spaces due to the high risk of predation.

Thirdly, habitat fragmentation and loss occur when railways are constructed, leading to the removal and disturbance of natural habitats. This can result in biodiversity loss and the creation of ideal conditions for invasive plant species to take root. Additionally, the regular mowing and herbicide treatment of railway verges can alter the vegetation composition, creating an environment that favours generalist and open-environment species over native species from the surrounding habitats.

Lastly, disturbances caused by trains can include pollution from diesel engines, sound, and vibrations. These factors can further deter wildlife from crossing train tracks and impact their overall well-being.

To mitigate these impacts, various measures have been proposed, such as wildlife passes, exclusion fences, and olfactory repellants. However, it is important to note that some mitigation strategies, such as exclusion fences, can increase the barrier effect if not combined with measures to facilitate wildlife movement across railways. Overall, trains can have significant disturbances on wildlife and their habitats, and careful consideration and effective mitigation strategies are essential to minimize these impacts.

Trains can reduce congestion and the number of cars on roads

Trains can indeed reduce congestion and the number of cars on roads. Rail service increases do decrease vehicle travel, but only by a small amount. However, it is important to note that no transit project or service has ever been the direct cause of a substantial drop in traffic congestion.

In the Pacific Northwest, 65% of the region's emissions come from transportation, with personal-use vehicles contributing to 43% of Portland's transportation emissions. The Washington State Department of Transportation's Cascadia High-Speed Rail project is expected to reduce the region's carbon emissions by six million metric tons. The project will also absorb at least 20% of intercity trips, including auto, air, and bus travel.

High-speed rail infrastructure can be incorporated along highway corridors, providing an alternative commuting option for drivers and reducing congestion in urban cores. For example, a high-speed rail station in Downtown Seattle would provide convenient access to the convention center and tech offices in South Lake Union. People could easily walk from Capitol Hill to a restaurant downtown or take a 15-minute train ride home to Tacoma or Everett.

Light rail systems can also reduce congestion by attracting new riders and promoting car-to-transit shifts. However, certain conditions must be met for this to occur, such as a net increase in transit service and accessibility, the potential demand for transit travel within the corridor, and ensuring that the new transit system does not interfere with or slow down roadway traffic.

In addition to reducing congestion, trains are also more environmentally friendly than cars. Electric trains, in particular, emit 20-35% less carbon than diesel trains and offer carbon-free journeys when powered by renewable energy. The greenhouse effect of gas emissions per kilometer on railway transport is 80% less than that of cars.

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