Why are train brakes so loud?

The squeal noise is supposed to be the result of the sound radiation of the structural components of the brake system in self-sustained vibrations. The self-sustained vibrations are supposed to be due to the dynamic instability of the sliding equilibrium of the system.



Train brakes are loud primarily because of the intense friction and vibration generated when stopping thousands of tons of moving metal. Most freight and many older passenger trains use "tread brakes," where a high-friction brake shoe (made of cast iron or composite material) is pressed directly against the steel wheel's running surface. This "metal-on-metal" contact creates high-frequency vibrations that we perceive as a piercing screech or squeal. Additionally, modern passenger trains often use compressed air systems (Air Brakes) to actuate the braking mechanism; when the brakes are released, the sudden "hissing" sound is the result of pressurized air being exhausted into the atmosphere. On high-speed trains, "disc brakes" are used, which are quieter than tread brakes but still produce a significant "whirring" or grinding sound due to the massive heat and force required to slow a train from 200 mph. The "shuddering" sound you sometimes hear at a stop is the anti-skid system (similar to a car's ABS) pulsing the brakes to prevent the wheels from locking up and sliding on the tracks.

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he brakes will be quickly applied. Typical noise levels due to air-brake operation range from 95 to 115 dB(A), in some cases as high as 120 dB(A).

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The squeal noise is supposed to be the result of the sound radiation of the structural components of the brake system in self-sustained vibrations. The self-sustained vibrations are supposed to be due to the dynamic instability of the sliding equilibrium of the system.

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Roughness and irregularities on the wheel and rail surfaces are a source of noise and vibration. Rail joints and squats on the rail cause a familiar clickety-clack sound as train wheels roll over them.

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Earplugs: Wearing earplugs can combat the train noise and help you sleep through the night. White noise: A white noise machine or app will provide a constant low-level background noise that can help you sleep through occasional train whistles.

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Noise pollution and vibrations are some of the biggest concerns, particularly for people who live within one-third of a mile of railroads or railyards, says Natalia Caldeira Loss Vincens, an expert in public health at the University of Gothenburg in Sweden.

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The reason that trains honk their horns so much at night is because it's dark and the trains aren't so easy to see. Even though the lights are on, we sometimes can't see them coming, especially around the many blind curves near or ahead of the train station.

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Trains also use horns, whistles, bells, and other noise-making devices for both communications and warnings. The engines in diesel locomotives and DMUs produce significant amounts of noise. Newer locomotives have become much quieter in recent years due to noise regulations being implemented by countries and regions.

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Why do trains honk so loud at night? To warn other vehicles they are coming. Particularly at junctions with roads. Usually its cooler at night, and colder air seems to transmit sound more readily.

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a magnet on the track, when the train runs over the magnet it will warn the driver to stop; a transmission loop that tells the train the signal is red, this will trigger the train computer to apply the brake.

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The mechanism of an emergency brake may differ, depending on railcar design. Emergency-braking a train (without track brakes) will give about 1.5 m/s2 (0.15 g) deceleration. The braking distance will be approximately 250 m (820 ft) at 100 km/h (62 mph) and 600 m (2,000 ft) at 160 km/h (99 mph).

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At age 62, I could push a train car down a track. Unlike a steam engine that would hammer the rails (a main reason why they were retired), modern railcars glide with low friction, and crushed rock underneath the tracks helps diminish impact. You won't hear it or feel it, Rangel says.

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Locomotive horns serve a utilitarian function and in North America with its wide open spaces, sparsely populated areas between cities and infrequent rail traffic (compared to Europe) a louder horn and more frequent blasting makes practical sense.

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If for no other reason, the horn can alert those folks to get to safety. either to alert people when they enter the tunnel(like MOW, or trespassers) or in some cases, to be friendly at kids(or railfans) at the tunnel entrance.

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Have you ever thought why trains blow their horns so often and so loudly? The truth is that they have to. And the main reason for that is safety. Locomotive engineers are required to honk every now and then, which is written down in the regulations called the Final Rule on the Use of Locomotive Horns.

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The length, height, width, and composition of the building and its distance from the tracks, determines its natural oscillating frequency and the train's length and speed must create an oscillation that closely matches the building's frequency (or its harmonics), so that the small train vibrations get amplified to ...

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“People assume that trains are loud, but that assumption is based on the fact that when a train's gone past them in a station it's noisy. That's because the noise a train makes is mainly projected to either side. When trains are moving directly towards you they are barely audible–until it's too late.”

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