Demonstration of train track change principle

Demonstrate the principle of train track change;

1. Relationship between train wheels and rails: The wheels of the train press on the rails to transmit the gravity of the train. The red part of the picture shows that there is a circle of disks with a larger radius inside the train wheel. This thing is called "rim". This thin layer of things makes the wheels not only pressed on the track, but also "stuck" in the track. This structure can ensure that the wheels always run on the track without derailment, which is used to control the running direction of the train.

2. Switch principle: The wheel rim is used to control the running direction of the train. "Turnouts can control the position and mode of the rim to realize rail change.

The schematic diagram of the first turnout has a moving part. When there is a small slit in this part, the rim can pass through the small slit and travel in the direction guided by the external rail. When the two tracks are closely attached, the rim is guided in the direction of the inner track.

When the red point rail on the picture is close to the right, open the A-B direction ... If you insist on the left, open the A-C direction.

Therefore, the running direction of the train depends on the opening direction of the turnout. The running direction of the train at the turnout is not controlled by the driver at all, but the opening direction of the turnout is controlled by the ground.

However, before the general train enters the station, the driver still needs to know the route, what turnout to pass, which track to enter and which direction to turn off.

3. "Interlocking" is a mechanism to ensure the mutual restriction between the route, turnout position and signal.

For example, a train should pick up from the downward direction and stop at the station 1 lane. Then the signalman will give an instruction to arrange the route to enter 1 lane in the interlocking system, and then the switches related to this instruction will start to switch, and all related switches will switch to the direction leading to 1 lane. The system will automatically detect whether all switches are in place. If all the switches are in place, the system will turn on the signal to protect this line, indicating that the train can enter. At the same time, shield other routes that conflict with this route.

In a word, under the constraint of interlocking rules, it can ensure that trains pass through different routes in the station and conflict at different times, so as to avoid train collision.