A railway line with a travel speed higher than 200km/h can be called a high-speed railway, which can be fully enclosed, with (or without) special signals and safety systems, and has little to do with whether it is a bullet train or not. But this definition is difficult to achieve, so almost all high-speed trains are high-speed trains. As for the bullet train, it refers to a rail vehicle that has its own power and can walk on a heavy-duty track by virtue of power. Whether it is high speed or not, as long as it can load the payload by itself and run. Subway and light rail are also a kind of bullet train.
EMU refers to the type of train. It is a unique name in China, which is different from the previous ordinary trains. Under normal circumstances, ordinary trains are towed by locomotives, and the carriages themselves have no power; The train car itself has power. When running, there are both locomotives driving and "running by themselves", so that the power can be dispersed and the running speed will be faster. At the same time, compared with ordinary trains, EMU has less vibration and noise. Therefore, bullet trains are different from ordinary trains. In China, trains with a speed of 200 and above and using CRH Harmony are called "EMU".
At present, there are CRH 1, CRH2, CRH3, CHR5, CRH6, CRH380 and other different models in China (there is no CRH4, because "4" is a homonym of "death", which is considered unlucky; Each model has a small division, such as CRH 1A, CRH 1B, etc. CRH6 has not been officially put into operation), which is called Harmony in Chinese and CRH in English, and is the abbreviation of "China Railway Expressway". Actually, no matter on the "high-speed rail line" or the so-called "bullet train line" in China, bullet trains run. The difference lies in the different models: CRH 1, CRH2 (except CRH2C) and CHR5 are all 200 km, with the designed operating speed of 200KM/H and the highest operating speed. CRH2C, CRH3 and CRH380 are 300 km models, with a design running speed of about 350KM/H and a maximum running speed of 380KM/H 1. High-speed railway refers to the transformation of existing lines (linearization and gauge standardization) to make the operating speed reach more than 200 km/h, or to build a new "high-speed line" to make the operating speed reach one hour.
2. According to international standards, urban rail transit trains are divided into three types: A, B and C, which correspond to train widths of 3m, 2.8m and 2.6m respectively. All rail transit lines using A-type or B-type trains are called subways, and 5-8 trains are used. The rail transit line with C train is called light rail (except subway line 8), and 2-4 trains are used.