At present, urban rail transit can be divided into metro and light rail system. For the difference between the two, some people think that the underground rail transit is called subway, whereas it is light rail. Some people think that the light rail is light rail, heavy is the subway. Neither division is scientific. So what's the difference between a subway and a light rail?

In fact, whether light rail or subway, can be built underground, ground or viaduct; Although the rail weight of subway is generally greater than that of light rail, in order to enhance the stability of the rail, reduce the workload of maintenance and repair, increase the reflux section and reduce stray current, both subway and light rail tend to choose heavy rail. The basis for the division of the two shall be the size of one-way maximum peak hour passenger flow. The maximum one-way peak hour passenger flow that the subway can adapt to is 30,000 to 60,000 person-times, and the maximum one-way peak hour passenger flow that the light rail can adapt to is 10,000 to 30,000 person-times. The design of metro and light rail, the difference between them in the first place in the subway is generally greater than 13 tons of axle load and the light rail less than 13 tons, second, in general, the plane curve radius should not less than 300 meters, and light rail is in commonly 100 meters to 200 meters, in addition, the number of subway each marshalling than light rail, vehicle capacity is also more.

In terms of transportation capacity, vehicle design and construction investment, light rail differs from subway. In fact, the ultimate difference, or the essential difference, is the traffic volume. The one-way capacity of the subway line reaches 30,000 to 70,000 person-times in the peak hour, while the capacity of the light rail line is 0. 60,000 to 20,000 person-times. The size determines the number of marshalling capacity (subway train up to 4-10 knots, light rail train for 2-4), determines the vehicle, decided the axle load, determines the length of the platform, is very important, involving the reserved land, land for urban is money, underground station directly involve the cost, so the prediction is very important).

To paraphrasing what our textbook says, "subway has actually become a historical term. Today's subway is not limited to the form of underground tunnels, but refers to the mass transit system with a one-way capacity of 30,000 to 70,000 people in rush hours. Operation line diversification, underground, ground, elevated three organic combination. In fact, in some foreign cities, the subway has been renamed, such as New York, San Francisco, Hong Kong and other places, has been called 'Mass Transit Rail' or 'Rapid Transit System'. This kind of rail transit system is usually constructed as a tunnel line in the downtown area and a ground or elevated line outside the downtown area.

In addition, for the subway and light rail, there is a misunderstanding from the perspective of vehicles, which is that the subway vehicles use the third rail for power supply while the light rail USES the catenary. In fact, now the power supply mode can not become a sign of difference, now a lot of new subway vehicles have adopted the catenary, after all, this way from the safety and other aspects have the third rail incomparable advantages.

Underground, Underground,Subway,Metro;

Light Rail Transit,LRT;

The subway is fast and the traffic volume is large, but the cost is high and the construction is difficult.

The light rail is also faster, but not as fast as the subway.

It is the appellation that convention becomes actually, essential distinction is hard to say, volume of traffic? Heavy rail? Axle load? Speed? There seems to be no accepted definition.

Check out Vukan Vuchic's Urban Public Transportation. He is an authority on international Public Transportation.

According to the categories of electromagnets used in maglev trains, they can be divided into two types: normal attraction type and superconducting repulsion type. The maglev train with normal guide magnet and guide rail is used as the magnetic conductor to make the body leave the guide rail through the mutual attraction between different magnetic poles. The air gap sensor is used to adjust the suspension gap (the suspension height is 10mm). It is suitable for medium and low-speed transportation in urban and suburban areas with low cost. Japan's HSST and Germany's TR express are both normally-guided maglev trains. Repulsive superconducting maglev train, it is operated and low temperature superconducting magnet technology to realize suspension, the suspension height is 100 mm, the immersion (268.8 oC) in low temperature superconducting materials electromagnetic coil groove, installed in the car, the coil resistance is zero, which produces a powerful magnetic field, to bury in the inductive magnetic field of the closed loop aluminum circle on the tracks of interaction, repel each other, and float, this type maglev train can run ultra-high speed can reach 1000 km/h (theory).