Permanent way facts for kids
The permanent way is the special path that trains use to travel. It includes the rails (the metal tracks), the ties (also called "sleepers" in some places), and the ballast (the crushed stones underneath). This strong structure is built to safely carry trains. It's called "permanent" because, a long time ago, workers would first build temporary tracks to move materials. Once the main work was done, these temporary tracks were removed, and the strong, lasting "permanent way" was put in place.
Contents
What Makes Up a Railway Track?
A railway track is made of several important parts working together. These parts help trains stay on the track and travel smoothly. Understanding each part helps us see how the permanent way supports heavy trains.
Rails: The Train's Path
The rails are the long, strong metal bars that trains roll on. They are usually made of steel. Rails are shaped to guide the train's wheels. This shape keeps the train from leaving the track. Rails must be very strong to hold the weight of trains.
How Rails Are Joined
Rails are often joined together to make very long tracks. In the past, rails were bolted together. This created small gaps for expansion in hot weather. Today, rails are often welded together. This creates a smooth, continuous track. Welding makes the ride much smoother for passengers. It also reduces wear and tear on the trains and tracks.
Sleepers: Holding the Rails Together
Sleepers (or "ties" in North America) are the pieces laid across the track. The rails are fastened to these sleepers. Sleepers keep the two rails at the correct distance apart. They also help to spread the weight of the train evenly. This prevents the rails from sinking into the ground.
Types of Sleepers
Sleepers can be made from different materials.
- Wood sleepers are common and have been used for a long time. They are treated to last longer.
- Concrete sleepers are very strong and durable. They are often used on busy lines.
- Steel sleepers are also used, especially in some parts of the world.
Ballast: The Stone Foundation
Ballast is the layer of crushed stone under the sleepers. It looks like a bed of rocks. Ballast does several important jobs:
- It holds the sleepers firmly in place.
- It helps to drain water away from the track.
- It spreads the weight of the train over a wider area of the ground.
- It allows for small adjustments to the track's position.
Track Foundation Layers
Below the ballast, there are other layers. These layers are called the formation. They are carefully prepared to support the heavy track. Sometimes, special mats are used under the ballast. These mats can help reduce noise and vibrations. They also improve drainage.
Different Kinds of Tracks
Not all railway tracks look exactly the same. Different types of tracks are used for different purposes. Some tracks are designed for high-speed trains. Others are for lighter trains or special uses.
Ballastless Track
Some modern high-speed railways use ballastless track. This means there are no crushed stones. Instead, the rails and sleepers are fixed directly onto a solid concrete slab. This type of track is very stable. It needs less maintenance than tracks with ballast. It is often used for very fast trains.
Ladder Track
Ladder track is an older or specialized type of track. It uses long sleepers that run parallel to the rails. These are connected by cross-ties, making it look like a ladder. This design can be very stable. It is sometimes used in places where space is limited.
Guided Busways
Sometimes, buses can also run on special tracks. These are called guided busways. The buses have small guide wheels that follow a raised track. This allows buses to travel quickly and smoothly. It combines features of both roads and railways.
Keeping Tracks in Good Shape
Railway tracks need regular care to stay safe and efficient. This work is called maintenance of way. Special teams and machines work to keep the permanent way in top condition.
Track Maintenance Tasks
- Inspecting tracks: Workers regularly check the rails and sleepers for damage.
- Replacing parts: Worn-out rails or broken sleepers are replaced.
- Adjusting ballast: Machines called tampers pack the ballast tightly around the sleepers. This keeps the track level and stable.
- Lubricating curves: In tight curves, special oilers apply grease to the rails. This reduces wear on the rails and train wheels.
- Repairing pull-aparts: Sometimes, in very cold weather, rails can shrink and pull apart. Workers use heat to expand the rails so they can be joined again.
Specialized Maintenance Machines
Modern railway maintenance uses large, powerful machines. These machines can do many jobs quickly.
- Track renewal trains can replace old tracks with new ones very fast.
- Tamping machines precisely adjust the position of the track and pack the ballast.
- These machines help keep trains running safely and on time.
Images for kids
-
New railway concrete sleeper.
-
Section through railway track and foundation showing the ballast and formation layers. The layers are slightly sloped to help drainage. Sometimes there is a layer of rubber matting (not shown) to improve drainage, and to dampen sound and vibration
-
Ballastless high-speed track in China
-
Diagram of cross section of 1830s ladder type track used on the Leeds and Selby Railway
-
Ladder track at Shinagawa Station, Tokyo, Japan
-
Bonded main line 6-bolt rail joint on a segment of 155 lb/yd (76.9 kg/m) rail. The alternating bolt head orientation is to prevent complete separation of the joint in the event of being struck by a wheel during a derailment.
-
Welded rail joint
-
A pull-apart on the Long Island Rail Road Babylon Branch being repaired by using flaming rope to expand the rail back to a point where it can be joined together
-
An expansion joint on the Cornish Main Line, England
-
Panama Canal construction track
-
Circa 1917, American section gang (gandy dancers) responsible for maintenance of a particular section of railway. One man is holding a lining bar (gandy), while others are using rail tongs to position a rail.
-
Flange oilers lubricate wheel flanges to reduce rail wear in tight curves, Middelburg, Mpumalanga, South Africa
-
Intercity-Express Track, Germany
-
On this Japanese high-speed line, mats have been added to stabilize the ballast
-
Buses driving on tracks
-
Track of Singapore LRT
-
Maintenance of way equipment in Italy
-
A track renewal train in Pennsylvania
-
Plasser & Theurer 09-32 CSM continuous action levelling, lining and tamping machine of the Romanian Railways
See also
In Spanish: Vía férrea para niños
