turnout is put a rail branch into two or more than two track
the locomotive is composed of a line is transferred to another line of the basic settings
turnout number using crossing number to represent the angle, fork heart on both sides of the working edge,
called the crossing angle, crossing angle of the cotangent value called a marsupial frog.
common switch is divided into single turnout turnout, symmetrical, double slip switches and cross line
turnout is a special rail equipment, not only affects the safe operation of the train, and the service life is short than other equipment, on-site maintenance workload.
china's most commonly used single turnout, its main line is straight line, lateral line by line to the left or to the right fork, also known as the left and right turnout turnout, which accounted for more than 90% of the total number of various types of switches.
single switch is one of the most common railway fittings, a movable turnout frog, refers to individual components can be moved, by what card train poor when trajectories are continuous, the elimination of single open harmful space existing fixed frog turnout, but also cancel the guard rail, and geometric single turnout frog in longitudinal section the ride can also be greatly reduced, thereby significantly reducing the interaction between single turnout frog parts of the wheel / rail, improve the operation and stability, prolong the service life of the frog.
按尖轨类型，道岔可分为直线尖轨道岔和曲线尖轨道岔两种。直线尖轨道岔的技术特点是尖轨较短，两根尖轨可对称制造，跟端为活接头，扳动灵活，稳定性稍差，需配置一台转辙机，侧向容许通过速度一般为30 km / h。曲线尖轨道岔的技术特点是尖轨较长，两根尖轨不可对称制造，跟端采用接头夹板连接，稳定性好，需配置两台或多台转辙机，侧向容许通过速度一般为 35 km/h。60 kg/m 钢轨9号直线尖轨及曲线尖轨单开道岔在我国城市轨道交通工程中均有广泛应用，技术均较成熟可靠。
according to the rail type, switch can be divided into linear split switch and curve split switch two. the technical features of linear split switch is the switch rail is short, two rail symmetric manufacturing, with end is a movable joint, pulling the flexibility, stability is a bit poor, need to configure a switch machine, lateral allowable by typically 30 km / h. the technical characteristics of sharp rail turnout switch rail curve is longer, two rail can not be symmetrical with the end of manufacturing, using the joint splint connection, good stability, need to be configured to two or more switch machine, lateral allowable by typically 35 km/h. 60 kg/m rail straight switch and curve rail turnout no. 9 are widely used in urban rail transit projects in china, are relatively mature and reliable technology.
1, to reduce the rail with end interval size to meet the requirements of kinetic energy loss;
2, plus a large turnout of guide curve radius to meet the unbalanced centrifugal acceleration and the unbalanced centrifugal acceleration time variable rate requirements, at the same time, proper redundancy;
3, plus a large turnout of guide curve radius is should ensure that the frog heel and the guide rail on curves round shun cohesion;
4, to reduce the rail with end interval size can be realized in the structure design.
turnout general layout design using linear rail, linear frog, curved guide curve, according to the need of insulation is arranged in the straight strands or side shares, such as shown in figure below, the main dimensions are as follows:
the total length of the switch: lq= 29986 mm;
switch front length: a =14 256 mm;
switch back end length: b =15 730 mm;
tongue tip before a basic rail length: q =2 410 mm;
rail length: l0= 6450 mm;
rail with end of the working side and the basic rail distance: t + b =144 mm;
the center of the line guide curve radius: r=190 m;
insert the frog front end section: k=1 558 mm;
the frog and the guard part adopts the structure type and the same original switches.