What are train couplers

train couplers

The rain couplers and connecting equipment are one important part of the train. They must have enough strength to bear the traction force of the whole train; they also need to have enough safety to avoid accidental disengagement, and they also need to have enough flexibility to provide rotation with buffering. To better meet these needs, the coupler design has also undergone several improvements.

Early train couplers are two hooks with holes, with a metal rod running through them. When the train is connected, the staff needs to insert the metal rod into the hole at the right time. This is a very dangerous job, and workers are often accidentally squeezed out of their fingers. Therefore, a safer and more efficient automatic coupler was born.

There are many types of automatic train couplers, the most common Janney coupler is used, and its basic structure is shown in the picture above. The reason why the Janney coupler is called an automatic coupler is that when either of the two couplers is open, it will automatically complete the connection with the other. When removing the hook, the hook needs to be lifted manually before the hook can be removed.

It should be noted that the ordinary Jen’s coupler can prevent the coupler from disengaging front and rear, but it cannot prevent the coupler from disengaging up and down. Under some extreme conditions, such as a new wheeled, empty truck coupled with a heavily loaded truck with extremely worn wheels, the coupler may disengage up and down when passing through extremely bumpy road sections. However, these only occur when the maintenance is extremely inadequate, and this situation does not occur in normal operation. In addition, the United States requires that tank trucks carrying hazardous chemicals must use Type E or Type F couplers. There are baffles on the upper and lower sides of the coupler to prevent the coupler from disengaging up and down.

Ordinary train couplers are not tightly connected, that is, there is still a certain gap after the coupler is locked. This gap is very important for the train, because when the train stops, due to the transmission speed of the wind pressure signal, there is a certain time difference between the front and rear vehicles braking, which makes the rear vehicle squeeze the front vehicle when braking. , so that the gap between the couplers is vacated. When the train starts, due to the existence of the gap, the locomotive will first drive the first car, then the coupler will be tightened and the second car will be driven, and so on, so as to avoid the train taking all the cars at once, because that will affect the train’s Traction makes higher demands.

There is a buffering device between the coupler and the underframe. This buffering device can reduce the impact of parking, starting, and connecting, and is essential to ensure passenger comfort and cargo integrity. Someone once tried to integrate the buffer device on the underframe of the vehicle, but it was eliminated because of poor effect.

Ordinary couplers cannot be rotated, so ordinary freight trains cannot be unloaded by dumpers. The so-called dumper is a machine that grabs and rotates the gondola, so that the cargo inside the car is dumped from the side, which can greatly speed up the efficiency of cargo loading and unloading. When the dumper is working, the vehicle is not disconnected from the train, so this method of unloading requires the vehicle to be equipped with a rotating coupler. A car only needs to be equipped with a swivel coupler at one end, which will be marked with a yellow square on the hull.

On EMU trains and some light rail trains, since the longitudinal impulse between trains needs to be minimized, tightlock couplers will be equipped on these trains, and some couplers will also integrate the connection of electrical pipelines to become semi-permanent couplers. These couplers are more sophisticated than Jen’s and are often not compatible with each other, requiring special adapters to connect them.