Why is there water on the subway tracks? How deep is the subway?

Subway is a form of rail transportation, referring to an urban rail transit system that mainly runs underground. It is the abbreviation of underground railway or subway. With the increase in rail transportation volume, as well as the increase in axle weight and travel speed of locomotives and vehicles, many new types of tracks have appeared one after another. Many friends are very curious about why there is water on the subway track. Let's take a look!

Contents of this article

1. Why is there water on the subway tracks?

2. How deep is the subway?

3. Why does the subway make a whistling sound?

Why is there water on the subway tracks?

The sources of water in the subway tracks include: water leakage in the section. According to the specification, cracks are allowed in the concrete of underground projects. Under the premise of "prevention first", the groundwater that leaks into the structure is diverted away by drainage. This is how the water in the track groove appears. A small part of the water is condensed water from the subway air conditioner.

Track refers to the route paved with steel strips for trains, trams, etc. to run.

With the increase in railway transport volume and the increase in axle weight and running speed of locomotives and vehicles, many new types of tracks have emerged one after another.

The classification of tracks includes seamless tracks, wide sleeper tracks, integral ballast tracks, slab tracks, etc.

How deep is the subway?

Subways are generally built about 20 meters underground. The four subway cities of Beijing, Tianjin, Guangzhou and Shanghai are built about 20 meters underground. The depth of Beijing's Line 5 reaches 24 meters. The depth of subway construction will vary depending on the soil, geology and line distribution.

The subway is a form of rail transportation, referring to an urban rail transit system that mainly runs underground. It is the abbreviation of underground railway or subway.

Subway is a fast, high-capacity, electric-powered rail transit system built in cities. Trains run on fully enclosed lines. Lines in the central city are basically built in underground tunnels, while lines outside the central city are generally built on viaducts or on the ground.

Why does the subway whistle?

Because the tunnel inside the subway is a relatively sealed environment, although there are ventilation holes in designated places, it is still relatively closed. When the train is running, the tunnel will have piston wind, which causes a certain squeezing state of the air, resulting in a whistling sound.

The whistling sound on the subway is the Doppler effect. When the train is approaching, the sound will become sharper and sharper, and when the train is moving away, the whistling sound will become duller and duller. And the faster the train is driving, the more obvious the Doppler effect will be.