Trains are fascinating and that’s nothing new about it. But there are some parts hardly noticed by the average passenger, yet very important in safe railway operations. Made you curious? Follow along…
Do trains have suspension?
To answer your question, yes, trains do have suspensions.
In order to go into details and talk about train suspensions, we have to find out a little bit about bogies(trucks).
And here comes the part I was mentioning earlier. Bogies are very important parts of a train, although hard to be noticed by passengers. A bogie( mostly called trucks in North America) is a frame, placed under the trains, onto which the wheels of the railway vehicle are fixed.
They are an essential part of the train, its drive system and guidance mechanism having the following role:
- Support the mass of the train firmly
- Stability on both straight and curved track
- Provide good ride comfort against the shocks transmitted from the track by absorbing vibration
Each railway vehicle (wagon, coach or locomotive) will usually have two bogies, generally located towards the vehicle's ends, 4 wheeled or 6 wheeled, used to provide vehicle body traction and for braking.
The wheels are pressed on to the axle so that they both rotate together.
A main component of bogies are suspensions. Their role is to absorb shocks between the bogie frame and the rail vehicle body and reduce vibrations felt inside the vehicle. This usually consisted of a leaf steel spring mounted on the axles, but progressed over the years into a more detailed suspension system.
There are two main types of suspension systems used in trains:
- Primary suspension system
- Secondary suspension system
The primary suspension include spring and damper components that are placed between the bogie and the wheel set, in order to support the structural suspension of the carriage and the rest of the train and to ensure low track forces, low wear and good behavior in curves.
The secondary suspension connects the body of the car with the bogie and offers comfort to passengers by isolating the vehicle from vibrations transmitted from the track.
The air spring is part of the secondary suspension of most modern passenger rail vehicles and is placed between the car body and bogie. Its main task is to reduce car body accelerations in the lower frequency range.