What Is The Rail Track Switch?

1.Overview of A Rail Track Switch

1.1 A rail track switch is a line connection device that enables locomotives and vehicles to transfer from one track to another. It is also one of the weak links in the track and is usually laid in large quantities at stations and marshalling yards. With rail track switches, the passing capacity of the line can be fully utilized. Even on single-track railways, by laying rail track switches and building a crossover line longer than the train length, trains can run in opposite directions. Rail track switches play an important role in railway lines.

2.Characteristics Of The Rail Track Switch

2.1 Due to the characteristics of a large number, complex structure, short service life, speed restriction for trains, low safety during operation, and high maintenance costs, rail track switches are regarded as one of the three weakest links in the track, along with curves and joints. There are three basic forms of rail track switches: connection, crossing, and the combination of connection and crossing. Common types of connection rail track switches include various types of single and double rail track switches; crossing types include vertical crossing and diamond crossing; and the combination of connection and crossing includes crossover and double crossover, etc.

2.2 Rail track switches are a large family, with the most common being the ordinary single rail track switch. It consists of three units: the switch, the connecting part, and the frog and guard rail. The switch includes the basic rail, the point rail, and the switch mechanism. When a locomotive or vehicle needs to transfer from track A to track B, the switch mechanism is operated to move the position of the point rail. Point rail 1 is in close contact with basic rail 1, and point rail 2 is separated from basic rail 2. In this way, track B is opened and track A is closed. The locomotive or vehicle enters the connecting part and transitions along the guide curve rail to the frog and guard rail unit. This unit includes the fixed frog heart, wing rail, and guard rail, whose function is to ensure the safe passage of the wheels through the intersection of the two tracks.

You may have noticed that there is a gap between the narrowest part of the wing rails and the tip of the heart. This is the harmful space of the rail track switch. When the wheels pass through this area, they may enter the wrong frog slot and cause derailment. The purpose of setting guard rails is to force the wheels to follow the correct direction. However, the existence of this harmful space limits the speed of trains passing through the rail track switch, which is very unfavorable for high-speed train operation.

2.3The fundamental solution to the harmful space of rail track switches is, of course, to eliminate it. Since ordinary rail track switches cannot do this, special rail track switches – movable heart rail track switches – must be developed.

3.The Feature Of The Rail Track Switch

The most significant feature of movable heart rail track switches is that the frog heart rail can be moved. When we need to open a certain direction of the track, the movable heart rail of the frog heart rail is in close contact with the wing rail in the opening direction and separated from the other wing rail. In this way, the harmful space of the ordinary rail track switch does not exist. Practice has proved that eliminating the harmful space of the rail track switch makes the operation more stable, and the speed limit for passing through the rail track switch is smaller. Therefore, it is particularly suitable for lines with large traffic volume and the need to operate high-speed trains.

4. Classification Of The Rail Track Switch

Rail track switches are important equipment for track switching and are widely used on railway lines. Nowadays, electro-hydraulic-controlled automatic rail track switches have replaced the outdated manual ones. Due to the large number of joints and complex curves in the rail track switch area, it is often a high-risk zone for train operation safety. Common types of rail track switches include single rail track switches, three-way rail track switches, crossover rail track switches, double crossover rail track switches, and connecting rail track switches etc. The structures of various rail track switches are shown in Figure 1.

4.1 A single rail track switch has a main line and a side line. The movement of the switch rail switches the rail track switch, and the switch machine controls the side line and main line switch. The single rail track switch is the most commonly used and typical type of rail track switch in the field.

4.2 A symmetrical rail track switch is a special type of single rail track switch. The entire rail track switch is symmetrical to the center line of the main line or the bisector of the frog angle. There is no distinction between the straight and side directions when a train passes through. When the switch rail lengths are the same, the angle formed by the switch rail’s working edge and the main line direction is approximately half that of a single rail track switch. When the radius of the guide curve is equal, the length of the symmetrical rail track switch is shorter than that of the single rail track switch. Under the same conditions, the radius of the guide curve of the symmetrical rail track switch is about twice that of the single rail track switch. When the radius and length of the curve remain unchanged, a smaller number of frogs can be used compared to the single rail track switch. Therefore, under the condition of a fixed rail track switch length, using a symmetrical rail track switch can result in a larger guide curve radius, which can increase the rail track switch speed. Under the condition of maintaining the same rail track switch speed, the symmetrical rail track switch can shorten the rail track switch length, thereby shortening the station length and increasing the effective length of the track. These characteristics of the symmetrical rail track switch make it applicable in hump yards, triangular lines, industrial railway lines and urban light rail lines.

4.3 A three-way rail track switch, also known as a compound asymmetrical symmetrical rail track switch, is a commonly used type of compound rail track switch. It is equivalent to two single rail track switches connected in the opposite direction, but its length is much shorter than the sum of the lengths of the two single rail track switches. Therefore, it is often used in the approach lines of railway ferries, hump marshalling yards, and areas with narrow terrain and special needs. A three-way rail track switch consists of one set of switch machines, one set of guide curves, and one set of connecting curves. Due to its complex running conditions, it should not be used unless it is necessary.

4.4 A double crossover rail track switch is equivalent to two single rail track switches laid in opposite directions, achieving the crossing of non-parallel tracks. It has the advantages of short rail track switch length, multiple switch routes, and both main running directions being straight. Therefore, it can save land, improve shunting capacity, and improve train operation conditions. A double crossover rail track switch consists of a diamond crossing, switch machines, and connecting curves.

Supplier

Luoyang Fonyo Heavy Industries Co., Ltd,founded in 1998,is a manufacturer in railway casting parts.Our factory covers an area of 72,600㎡, with more than 300 employees, 32 technicians, including 5 senior engineers, 11 assistant engineers, and 16 technicians.Our production capacity is 30,000 tons per year. Currently, we mainly produce casting, machining, and assembly for locomotive, railcar, high-speed trains, mining equipment,wind power,etc.
We are the railway parts supply to CRRC(including more than 20 branch companies and subsidiaries of CRRC),Gemac Engineering Machinery,Sanygroup, Citic Heavy Industries,etc. Our products have been exported to Russia, the United States, Germany, Argentina, Japan, France, South Africa,Italy and other countries all over the world.