Why are trains not aerodynamic?

Why aren't subway trains aerodynamic? Speed and capacity are the main reasons. In terms of speed, a lot of it has to do with how frequently the train starts and stops, as well as the track conditions.



It is a common misconception that trains are not aerodynamic; in fact, high-speed trains (like the Shinkansen or TGV) are among the most aerodynamically engineered vehicles on earth. However, for "standard" commuter or freight trains, they often look "blocky" because of operational practicality and speed thresholds. Aerodynamic drag only becomes a major energy-waster at speeds above 60–70 mph (100 km/h). For a slow-moving freight train or a subway car that stops every mile, the cost of adding complex aerodynamic fairings outweighs the fuel savings. Additionally, trains must be "double-ended" so they can travel in both directions without being turned around, which often results in a less-than-perfect "tail" design. There is also the issue of train-track interaction; a train's wheels are tucked under the body, and the gap between the cars creates "vortex shedding" that is very difficult to smooth out without making the train a single, inflexible unit. Finally, many trains are shaped to fit within "loading gauges" (tunnels and bridges) built over a century ago, forcing a rectangular profile that prioritizes passenger head-room over a sleek, teardrop shape.

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If you can't walk or cycle, then public transport is usually your best option. Trains are particularly low-carbon ways to travel. Taking a train instead of a car for medium-length distances would cut your emissions by around 80%. Using a train instead of a domestic flight would reduce your emissions by around 86%.

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Usually, planes are faster than trains, but if a plane flies very slow and a train moves very fast, they can travel at the same speed.

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Over time, ballast is crushed or moved by the weight of trains passing over it, periodically requiring relevelling (tamping) and eventually to be cleaned or replaced. If this is not done, the tracks may become uneven, causing swaying, rough riding and possibly derailments.

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However, as an energy researcher, my decision was motivated by the fact that trains, whether for cargo or passengers, pollute much less than airplanes, sometimes by as much as 73%, and they are more easily electrified than planes.

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Railroad tracks guide the train, acting as the low-friction surface on which the train runs and often transferring the weight of the train to the ground below. The track may also provide electrical power along the third rail, as you'll recall.

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But trains are still only the second-safest option, with the first-safest option being — you guess it — flying. According to that same study, the number of deaths per billion passenger-miles caused by airplanes is a measly 0.07. And this statistic is just one of many that illustrate just how safe air travel is.

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Size and Length: Freight trains are typically very long and can consist of dozens or even hundreds of cars. Because of their size, it takes more time for the entire train to pass a fixed point, giving the impression of slower movement.

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Finally, the plane is the most polluting means of transport and the one that generates the most greenhouse emissions.

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These massive, track-mounted vehicles, which use a diesel generator to power electric motors and move rail cars carrying cargo or passengers, are major polluters, responsible for a growing share of the emissions that increase cancer risk, shorten lives and worsen smog across California.

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If we take an overall view of the transport sector, 71% of transportation related carbon emissions come from road users, whereas only 1.8% of emissions stem from rail travel. So in absolute terms, trains are responsible for a lot less emissions than cars.

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Generally laid perpendicular to the rails, ties transfer loads to the track ballast and subgrade, hold the rails upright and keep them spaced to the correct gauge. Wooden ties are used on many traditional railways.

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Wood has the natural flexibility that is perfectly suited for the loads running on railroad tracks every day. Wood ties are engineered to perform under heavy load conditions. The durability of the wood tie means lower costs for railroads.

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Narrow gauge railroads tend to cost less to build, but may have lower weight limits. Standard gauge lines may cost more initially, but typically weight limits will be higher.

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