Single switch classification

Single-track turnouts are classified according to rail types, including 60, 50 and 43㎏/ m single-track turnouts. One-way turnouts are classified according to turnout numbers, including No.6, No.7, No.9, 12, 18, No.24, No.30, No.38, etc. Among them, No.6 and No.7 one-way turnouts are only used under the internal railways or humps of factories and mines, and other numbers are suitable for the main railway lines and station lines, with No.9 and 12 being the most commonly used. The turnout number n is calculated according to the cotangent of frog angle α, that is, cotα. According to the plane form of turnout, there are mainly single turnout with straight track frog, single turnout with bending center track and single turnout with bending center track frog. According to the structural types of turnouts, there are single-opening turnouts, interval turnouts and flexible single-opening turnouts with common and special rail sections. According to the frog structure, there are fixed and movable rail single turnout. One-way turnout is classified according to the type of turnout sleeper, including wooden turnout and concrete turnout.

In the past, turnout sleepers were mainly wooden sleepers, but now concrete turnout sleepers with 50㎏/ m and 60 kg/ m rails are widely used, with the number 12. In order to prevent conversion equipment from occupying sleeper space and meet the needs of large-scale road maintenance machinery and equipment, steel turnout sleepers are adopted in the design of speed-increasing turnout. The turnout sleepers laid on the switch and connecting part of single-track turnout are perpendicular to the straight line direction of turnout; The turnout sleeper in the frog part is perpendicular to the angle bisector of the frog angle, starting from the second turnout sleeper in front of the frog tip, and gradually turning from the direction of the vertical angle bisector to the direction perpendicular to the straight strand. In order to improve the running conditions when the train passes through the straight turnout, the turnout sleepers in the speed-increasing turnout are all arranged in the direction perpendicular to the straight track, with a spacing of 600㎜.

The cross section of wooden turnout sleeper is slightly larger than that of ordinary wooden sleeper, and the length of 0 degree is divided into 12 grades, of which the shortest is 2.60 m, the longest is 4.80 m, and the grade difference is 0.20 m. The wooden turnout sleeper and the backing plate are connected by spiral spikes.

The longest concrete turnout sleeper is 4.90m, and the grade difference is 0 0. 10/0m ... The concrete turnout sleeper and type III concrete sleeper have considerable effective supporting area and are in the form of no shoulders. The plastic sleeve is embedded in the turnout sleeper, and the lateral load is borne by the friction between the fastener and the screw screwed into the sleeve, and the reinforcement is φ 7 mm ..

The electrical conversion equipment of steel turnout sleeper is installed in the inner cavity of steel turnout sleeper, which can ensure that sufficient tamping space is formed between steel turnout sleeper and adjacent turnout sleeper. There are insulators between the steel turnout sleeper, the pad and the external locking equipment, which are welded at the bottom, and the bottom baffle has irregular strips to increase the friction coefficient with the ballast bed.

The parts to be considered in widening the turnout gauge include: the gauge of the joint before the basic rail, the gauge at the tip of the switch rail, the gauge at the heel of the switch rail, the gauge at the middle of the guide curve and the gauge at the end of the guide curve. The gauge of each part of the turnout is widened and appropriate gauge reduction is adopted to ensure the stability of traffic. In the newly designed turnouts (such as speed-increasing turnouts) in China, except for the widening of the gauge structure at the 2 mm width of the point rail, the rest of the gauge is1435 mm.

Geometrical dimensions of turnouts The dimensions of turnouts mainly include curved switch rail length, vertical switch rail length, front end length of basic rail, rear end length of basic rail, curved radius of switch rail, switch angle of switch rail and switch heel distance of switch rail. The frog size mainly includes toe distance, heel distance and frog length. In addition, there are the length before turnout, the length after turnout, the theoretical length of turnout, the actual length of turnout, the length of straight line inserted after guide curve or the radius of guide curve.

classify

Since there are single turnouts, there are double turnouts, three turnouts and multiple turnouts (multiple turnouts).

Double turnout is Y-shaped, that is, the two lanes connected with the turnout branch to both sides.

A three-way switch is like a ψ-shape, which connects three tracks at the same time. Two sets of switch machines operate two sets of switch rails.

The composite turnout is X-shaped, which is actually equivalent to the combination of four groups of one-way turnouts and a pair of rhombic crossings.

In addition, there is a kind of crossing equipment, which is usually called diamond crossing. It consists of two groups of acute frog and two groups of obtuse frog, but there is no turnout, so it is impossible to change lanes between tracks.

If the upper two points and the lower two points of the X-shape of the composite turnout are connected respectively, it is a crossing line. It can not only drive in more directions, but also occupy less land, so it is often used in stations.