Switch Machine

The switch machine is an important basic signal equipment, which is used to realize the switch conversion and locking. It is directly related to the safety of driving. It plays a very important role in ensuring the safety of driving and improving the transportation efficiency.

Item 4: basic signal equipment switch machine (theoretical part)

I. Turnouts

Turnout is the line equipment for rolling stock to transfer from one track to another, which is an important part of the track and one of the weak links of the track.

1. Turnout structure

Turnout consists of switch part, connection part and frog part.

(1) Switch part: it is composed of switch rail, basic rail, connecting parts (including connecting rod, sliding bed plate, base plate, rail support, top iron, switch rail heel structure, etc.) and switch machine.

(2) Connecting part: it is composed of guide rail and basic rail, which connects the switch part and frog part into a complete set of turnouts.

(3) Frog part: it consists of frog center, wing rail, guard rail, etc.

According to the purpose and plane shape, turnout can be divided into four types: single turnout, symmetrical turnout, three turnout and cross turnout. The single switch divides a line into two lines, the main line is in a straight direction, and the side line branches from the main line to the left or right side, which is widely used in the line connection.

2. Turnout number

The cotange value of turnout frog angle is called turnout number or frog number.

The standard turnouts commonly used in metro lines are No.7, No.9 and No. 12. 9 turnouts shall be used for main line and turn back line. In order to drive safely and stably, the train crossing speed shall be limited to a certain extent, as shown in table 4-1, in which the turnout in the train yard is basically No.7 turnout, and its lateral passing speed is 25km / h.

2、 Switch machine overview

1. Function of switch machine

In the centralized interlocking equipment, the function of the switch machine is to drive the switch conversion after receiving the command, as shown in Figure 4-2. Its main functions are: switch conversion, switch locking and switch position indication.

The turnout has two movable switch rails, one is closely attached to the basic rail, and the other is left. The position of the two switch rails can be changed at the same time to separate the original close rail. However, the original close rail can be seen that the turnout has two positions that can be changed.

The specific performance is as follows:

1) Switch the switch to the position or reverse position according to the operation requirements.

2) After the switch is switched to the specified position and closely pasted, mechanical locking is automatically carried out to prevent external force from changing the switch position.

3) When the switch rail is closely connected with the basic rail, the position of the switch shall be correctly reflected and the corresponding indication shall be given.

4) In case of switch extrusion and switch being in "four open" position for a long time (switch rail is not closely attached to basic rail), alarm shall be given in time.

2. Basic requirements for switch machine

1) As a converter, it should have enough pulling force to drive the switch rail to move back and forth in a straight line; when the switch rail is blocked and cannot be converted to the end, it should be restored to its original position through operation at any time.

2) As a locking device, when the switch rail and the basic rail are not closely attached, they shall not be locked; once locked, they shall not be wrongly unlocked due to the vibration when the vehicle passes through the turnout.

3) As a supervisor, it should be able to correctly reflect the state of turnout.

4) After the switch is squeezed, the switch shall not be changed before repair.

3. Classification of switch machine

(1) According to the action energy and transmission mode, it can be divided into electric switch machine and electric hydraulic switch machine.

The electric switch machine is powered by the motor and adopts the mechanical transmission mode. ZD6 series and S700K switch machine are all electric switch machines.

The electro-hydraulic switch machine is powered by the motor and adopts the hydraulic transmission mode, which is called electro-hydraulic switch machine for short.

(2) According to the power supply, it can be divided into DC switch machine and AC switch machine.

(3) According to the locking mode, it can be divided into internal locking switch machine and external locking switch machine.

4. Setting of switch machine

Generally, a group of switches are pulled by a switch machine. If No.9 at switch is adopted for the main line, two switch machines are required for the switch track part.

5. Operation and locking of switch machine

(1) There are two ways to operate the switch machine: electric conversion and manual conversion.

When the equipment is normal, the operating personnel use the relevant buttons on the console (or display) for centralized operation.

In case of power failure, switch machine failure and relevant track circuit failure, only the switch can be switched by hand.

(2) Locking means to lock the turnout by mechanical and electrical means to fix the turnout that the train is passing through or has issued instructions to allow the train to pass through (for example, handle the route), so as to prevent the turnout from wrong conversion.

There are two ways to lock turnout: mechanical locking and electrical locking.