Why doesn t high speed rail turn? How high speed rail turns

First of all, the construction of high-speed rail should take into account social factors, high-speed rail is not only through the starting point and end of the two cities, it also needs to communicate along the various stations, such as the world's longest Beijing-Guangzhou high-speed railway, it passes through Shijiazhuang, Zhengzhou, Changsha and other important cities, these cities are not in the same straight line, natural high-speed rail can not be built in a straight line.

Secondly, the natural conditions also have a great impact on the construction of high-speed rail, as we all know, our country has a vast territory and complex mountains and rivers. For example, the Beijing-Shanghai high-speed railway not only crosses the flat North China Plain, but also passes through the Jiangnan region, which is covered with a dense river network. Generally speaking, the cost of building a bridge is much lower than that of drilling, if it is built according to the straight-line distance between Beijing and Shanghai, this high-speed railway is only more than 1,000 kilometers, but in order to avoid the mountainous area, the high-speed rail can only bypass Jinan and Xuzhou, the distance has reached more than 1,300 kilometers.

Finally, the technical difficulty also limits the construction of high-speed rail, high-speed rail is not better than the road, the turning arc of high-speed rail is relatively large, that is to say, it can not make drift, sharp turn and other actions, if there is an obstacle ahead, the high-speed rail will turn in advance, draw a large arc, so as to avoid the train derailment due to too rapid turn, so we see the high-speed rail will show a curved state. At present, the construction of high-speed rail in our country is still limited by the three elements of economy, nature and technology.

In fact, the high-speed rail has to turn the same, but the amplitude of its bend is very small, and it is basically impossible to see, so it is said that there is no turn.

aqui te amo。

Because the speed of high-speed rail is generally faster, it is more dangerous if there is that kind of turn, so the route of high-speed rail is generally straight.

The high-speed rail will turn, just because the radius of the turn is too large for the person sitting in the car to feel, which makes many people mistakenly think that the high-speed rail does not turn.

The high-speed rail can turn slightly, but the amplitude of the turn can not be too large, because if the high-speed rail steering is too large, he has a different wheelbase and one of the important functions of the bogie, which may have a certain period of time, and the speed is too fast, and the turning is easy to produce friction.

The reason why this is so is because the speed of the high-speed rail is relatively fast, and it can't be said that he doesn't turn, but the turning amplitude is relatively large, so it looks like there is no turn! The speed is too fast, and it is relatively big from the heart!

The high-speed rail does not turn because it has a speed limit, and if he turns the case, he will not be able to reach that speed, so the high-speed rail is in a straight line.

It's fast, you can't turn a corner.

Too fast to turn.

High-speed rail does not have a steering wheel, but it has a bogie, which is equivalent to the role of a steering wheel. The only difference is that the bogie is not in the cab, but under the car. Everyone knows that the speed of high-speed rail can be maintained at the fastest speed of more than 300 kilometers per hour, and the body of high-speed rail is very long, so the radius when turning is very large.

When the high-speed rail enters the curved rail, the outer wheel side is wide and the inner surface of the outer rail is in contact, and in the process of squeezing each other, a force will be generated, which can make the bogie rotate along the curve of the rail, so that the high-speed rail can turn.

The turning radius of high-speed rail is relatively large, and the turning radius of the track with a general speed of 350 kilometers per hour is more than 8 kilometers, because the faster the speed, the larger the turning radius. When turning, the outside of the track will be a little higher than the inside of the track. Of course, turning also depends on the train's bogie with good performance.

First of all, it is necessary to see how the wheels and rails are in contact with each other.

Turns are achieved by changing tracks and directions.

Trams need an intersection where they make a left turn, and if parallel social vehicles make a U-turn at this intersection again, there will be a conflict in the trajectory. The design of the no-U-turn marking is precisely to prevent such traffic accidents.

As of December 31, 2019, Chinese mainland has opened a total length of urban rail transit lines, including metro kilometers, light rail kilometers, monorail kilometers, urban express rail kilometers, modern tram kilometers, maglev transportation kilometers, kilometers.

In the past, they could be distinguished by the weight of the rails, but today both rail systems use the same weight rails; It can only be distinguished by the type of vehicle body, system capacity (load and capacity); The traditional tram does not belong to the scope of light rail, and its capacity cannot meet the standard of the People's Republic of China on light rail (100,000 passengers per day, 10,000 passengers per hour at the peak), and can only be classified as a bus; Although the traditional tram can also increase the marshalling, it is greatly limited to transport.

Although the traditional tram can also increase the marshalling, it is very limited, and the traffic capacity is far from reaching the minimum of 10,000 people per hour and 5,000 per hour. This capacity is not easy to reach even with modern trams. The departure interval of general vehicles is about 5 minutes, the most dense is 2 3 minutes, the tram is seriously affected by mixed traffic, so the limit of peak transmission capacity is only a theoretical value, the peak transmission capacity of the actual tram is very difficult to exceed 10,000, mixed traffic is also a factor that distinguishes the tram from the light rail and subway.

1] Light rail features.

1) Train operation uses an automated signaling system.

2) Trains operate on dedicated tracks and stations.

3) The maximum speed of the train can reach 200 kilometers per hour.

4) The maximum train formation is 4 cars.

5) The light rail line has a one-way hourly capacity of 130,000 people (up to 370,000 people in the subway).

Radius + centrifugal force = inclination of the two tracks.

The high-speed rail bogie is actually a "small car" composed of two wheelsets on the frame, which is about the same size as an ordinary car, and the EMU carriage rests on this "small car", and it can rotate to a certain extent. There are two under each carriage, and because they are installed under the carriage, it is not easy for us to see what it looks like.

What does a bogie really look like? Take a look at the picture below and you'll see it clearly.

One of the important functions of the bogie is that it is used for railway vehicle steering, that is, cornering.

We know that trains don't have steering wheels, so how does it get through curves? When the vehicle begins to enter the curve at a certain speed, the outer wheel rim of the front wheel pair is in contact with the inner side of the outer rail, and the guiding force is squeezed to produce a guiding force, and the guiding moment is caused by the guiding force, so that the bogie rotates relative to the line.

In addition, the railway gauge is fixed, with the outer track long and the inner track short on the curve. The part of the wheel that is in contact with the rail is called the tread, and the tread is designed to be tapered in order to solve the problem of the wheelset passing through the curve. When the wheelset passes through the curve, because the tread has a taper, after the wheelset moves outward, the diameter of the contact point between the outer rail and the wheel is large, and the walking distance is long, and the diameter of the contact point between the inner rail and the wheel is small, and the walking distance is short, so that the curve can be passed smoothly.

Schematic diagram of the bogie passing through the curve principle.

Another benefit of the taper tread of the wheels is that they are self-centering in straight lines. The trajectory of the vehicle is actually a snake movement, due to the swing of the wheels from side to side, the contact diameter is constantly changing, and the use of taper tread plays the role of automatic centering.

How does a bogie adapt to high-speed operation?

With the increase of speed there is a problem, the serpentine movement of the vehicle will be unstable, once unstable, the wheels will violently impact the rail, and even cause derailment and overturning, which is absolutely not allowed by railway safety. Instability in serpentine motion must be avoided.

Schematic diagram of the principle of the serpentine motion of the vehicle.

Is there a way to make the EMU run at high speed without snake movement instability? The answer is yes. The high-speed bogie adopts axle box elastic positioning, air springs, axle box springs, various shock absorbers, arc wheel tread and other measures to ensure that there is no snake movement instability within the range of vehicle running speed.

Through the optimized design, the critical speed of instability of the bogie of the high-speed EMU can reach more than 500 km h.

In addition to supporting the carriage, the bogie is also responsible for transmitting the traction and braking force of the train to the wheels.

The bogie is divided into bullet car bogie and trailer bogie, the motor car bogie is equipped with traction motor, gearbox, wheel disc brake, etc., the trailer bogie is equipped with axle disc brake, and the high-speed bogie is generally made of high-strength alloy steel lightweight frame, hollow axle, aluminum alloy gearbox, air spring, shock absorber, etc.

To sum up, the bogie mainly has the functions of bearing, guidance, vibration damping, traction, braking, etc., and the high-speed EMU is inseparable from the "scud" of the bogie to run fast. (Xi'an EMU Depot).

You can search for high-speed rail bogies and general-speed train bogies.

It may also be understood by the turn of the car.

Because it is necessary to turn, it is possible to turn.

The railway curve is basically a large slalom, and the track is higher than the inside on the inside and outside of the curve radius, and the centripetal force generated is greater than the centrifugal force, so it will not roll over.

From a physical point of view, the railway curve is basically a large gyration, and the track is higher than the inside on the inside and outside of the curve radius, and the centripetal force generated is greater than the centrifugal force, so it will not roll over.

High-speed rail: Definition: High-speed rail (high-speed rail) has different standards depending on the era and different countries.

For example, in the early days of Western Europe, high-speed railways were designated as high-speed railways with a speed of 250,300 kilometers per hour for new construction and 200 kilometers per hour for the reconstruction of old lines. However, in 1985, the United Nations Economic Commission for Europe signed an agreement on international railway trunk lines in Geneva, stipulating that the speed of new high-speed railways for passenger trains should be more than 350 kilometers per hour, and the speed of new high-speed railways for mixed passenger and freight trains should be more than 250 kilometers per hour.

Because when the high-speed rail is turning, the track will be inclined to a certain extent, helping to overcome the centrifugal force when the high-speed rail is turning.

There is no mechanism on the high-speed railway, because the speed does not produce centrifugal force within a certain range, so it will not roll over, and when the speed reaches the maximum value, it will roll over.

The speed of the high-speed rail is very fast, and the reason why the high-speed rail rarely rolls over when it turns is because the high-tech instrument operator will not let him overturn.

The secret lies in the rails, when turning, the outer rails are higher than the inner rails, and the train passes through the arc rails at a certain speed, and the centrifugal force is equal to gravity, so that the balance can be maintained without overturning.