According to the weight, rails can classify to 38kg/m rail, 43kg/m rail, 50kg/m rail, 60kg/m rail, 75kg/m rail, etc. 43kg/m rail and above rails are commonly referred to as heavy rail.
It is mainly divided into hot rolled rail and heat treatment rail. In fact, the rail is produced by hot rolling process. The heat treatment rail is retreated again after hot rolling, which is divided into two kinds of on-line heat treatment and off-line heat treatment. The on-line heat treatment is already the mainstream, and it is more energy saving and more efficient.
The rail is a complex alloy. In addition to the main component iron (Fe), there are five major elements, carbon (C), manganese (Mn), silicon (Si), phosphorus (P), and sulfur (S). Of course, there are also a number of decisive micro Yuan Sufan (V), chromium (Cr), and some rare earth elements. These elements are fused with each other. Different manufacturing processes create different physical properties of rails.
High Speed Rail: the track in the station (the parking lot) uses 60kg/m rails (some station uses 50kg/m rail), the main line (including the station line, auxiliary line) is also 60 kg/m rail, but the rail of the high speed rail is very high, the flatness and the dimensions of each part are higher.
Ordinary railway: the passenger and freight railway before the completion of the high-speed rail (now still in operation), the depot and the parking lot are 50 kg/m rails, the main line is the 60 kg/m rail.
Heavy Haul Railway: similar to the great Qin, Shuo Huang railway and Shenhua coal special line and so on, the train axle is very important and the weight is large. The load of a train can reach more than 10 thousand tons (as a contrast, about 100 tons of ordinary subway). This type of railway generally uses 75 kg/m rail specially made, which can greatly increase the service life.
Alpine Railway: in particular, the Qinghai Tibet railway, which passes through the permafrost zone, has a very high requirement for cold resistance and corrosion resistance of rail, and uses the 60 kg/m rail specially manufactured.
Metro: the domestic subway is basically used in the parking lot with 50 kg/m rails, and the main line has 60 kg/m rails. Of course, the old metro line uses 50 kg/m rails...
Tram: trams are easy to derail because of their small wheels, small turning radius and small turnout numbers, so they choose the grooved rail with their own guard rail.