Why do trains squeal on corners?

Rail squeal is a screeching train-track friction sound, commonly occurring on sharp curves. Squeal is presumably caused by the lateral sticking and slipping of the wheels across top of the railroad track. This results in vibrations in the wheel that increase until a stable amplitude is reached.



People Also Ask

There is a lot of friction between the flanges and the ball of the rail. This friction is what generates the sound.

MORE DETAILS

Wheels and rails have the shape they do to allow curves to be negotiated – if there was less clearance between the rails and the wheels, they would constantly be rubbing and making flange strike the gauge face, causing the high pitch noise and excessive wear on wheels and rails.

MORE DETAILS

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.

MORE DETAILS

Generally, squeal noise of 100–110 dB is generated when a train passes through a curve about 7.5 m from the center of the rail; this is 15–20 dB higher than the rolling noise of the vehicle, and one or more pure tone noises occur at frequencies of 400–10,000 Hz [5].

MORE DETAILS

The clickety-clack of a train rolling along a railroad is a familiar sound to many people. This unique sound is caused by train wheels passing over rail joints, which are used to hold sections of rail together. The joints are needed in locations where full welded rail is not possible.

MORE DETAILS

Siegel: Now, Eric told me that the screeching happens when trains are going around a curve — where you have steel from the wheels rubbing against more steel from the tracks. And the Green Line in particular has a lot of these sharp turns.

MORE DETAILS

The horn needs to sound 15 to 20 seconds before the train arrives at a grade crossing, an area when road and rail intersect. They are also required to sound a short blast of noise if they see anything on the tracks. If it's an animal, a deer or cat, a sharp report from the horn usually scares it away.

MORE DETAILS

Why do trains sound their horn? Federal law requires the train crew when approaching a road crossing to sound the horn at all public crossings for the protection and safety of motorists and pedestrians regardless of whether crossings with gates and lights are present.

MORE DETAILS

Locomotive horns are required to sound for 15-20 seconds before entering all public grade crossings, but not more than one-quarter mile in advance. The required pattern for blowing the horn is two long, one short and one long sounding horn, repeated as necessary until the locomotive clears the crossing.

MORE DETAILS

But what was measured exceeds that limit: The samples show the average noise levels on all subway platforms and on all subway rides (inside subway trains) is between 72.5 and 76.5 dB and between 74.1 and 75.8 dB, respectively.

MORE DETAILS

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.

MORE DETAILS

Trains can't stop quickly or swerve. The average freight train is about 1 to 1¼ miles in length (90 to 120 rail cars). When it's moving at 55 miles an hour, it can take a mile or more to stop after the locomotive engineer fully applies the emergency brake.

MORE DETAILS

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.

MORE DETAILS