How Are Modern Railways Constructed?

Summary

This video from Railways Explained delves into the world of heavy railway machinery, exploring track laying, renewal, and maintenance machines. It covers the evolution of these machines, their functions, and the processes involved, from laying ballast to tamping and cleaning, highlighting the complexity and efficiency of modern railway infrastructure.

Takeaways

• 🚂 The script discusses the complexity and multi-dimensionality of the railway system, highlighting the specialized machinery involved in railway construction and maintenance.
• 🛠️ The development of railway machinery has evolved from manual construction to mechanized operations, which are more efficient and reduce the need for manual labor.
• 🏗️ Railway track laying machines are designed for continuous-action and assembly-line methods, ensuring cost-efficiency in track construction.
• 🛤️ The process of laying railway tracks involves several steps including earthworks, laying of the track formation, ballast, sleepers, and rails.
• 🔄 There are two primary methods for laying tracks: one where sleepers and rails are laid separately, and another where they are pre-assembled and laid together.
• 🔩 Railway track renewal machines are complex, capable of removing old sleepers, untying rails, and preparing the track bed for new materials.
• 🚆 High-speed railways often use thermite welding or continuous welded rail to connect rail sections for a stable and smooth track.
• 🛠️ Ballast tamping machines are used to pack the ballast under tracks, improving the durability of the track's superstructure and substructure.
• 🔄 Ballast cleaning machines specialize in cleaning and maintaining the railway track ballast, removing worn materials and replacing them with fresh ballast to ensure proper drainage and track stability.
• 🛑 The script mentions the use of a Virtual Private Network (VPN) for internet security and access to geo-restricted content, as a sponsored message within the video.
• 👥 The video is aimed at railway enthusiasts and those interested in learning about the heavy machinery and processes involved in railway infrastructure.

Q & A

What is the main focus of the 'Railways Explained' video?

The video focuses on the heavy railway machinery used for constructing and maintaining railway tracks, which might not be well known to the general audience.

Why is it suggested to watch the 'What are the Purpose and Elements of the Railway Track?' video before this one?

It is recommended because understanding the elements of the railway track is fundamental to fully comprehend the complex machinery and processes discussed in the video.

How have railway lines traditionally been built and maintained?

Traditionally, railway lines were built and maintained manually with simple equipment, tools, and construction technology.

What is the significance of the track formation in railway construction?

The track formation serves as a stable foundation for the sub-ballast and ballast layers, significantly impacting rail track performance and maintenance.

What is the difference between the two methods of track-laying mentioned in the script?

The difference lies in the order of laying sleepers and rails. In one method, sleepers are laid first, then rails are fastened to them. In the other, rails and sleepers are combined to form a track grid and laid together.

How does a track construction machine with a self-propelled gantry function?

The self-propelled gantry moves to the sleeper receiving conveyor, deposits the sleeper, and returns to the supply car for another load, ensuring a continuous supply of sleepers to the construction site.

What is the purpose of the thermite welding method in high-speed railways?

The thermite welding method is used to link rail sections, creating a continuous welded rail that is crucial for the smooth operation of high-speed trains.

What does the railway track renewal machine do and why is it complex?

The railway track renewal machine removes old sleepers and rails, prepares the track bed for new materials, and lays new sleepers and rails. It is complex due to the integration of multiple machinery units for various tasks involved in track renewal.

What is the role of the ballast tamping machine in maintaining railway tracks?

The ballast tamping machine packs the ballast under the railway tracks to increase the durability of the superstructure and substructure, ensuring a stable and long-lasting track foundation.

How does a ballast cleaning machine improve the effectiveness of the ballast?

A ballast cleaning machine removes worn and rounded ballast, screens it, and replaces it with new ballast, restoring the angularity and interlocking properties that are essential for good track support and drainage.

What is the advantage of combining tamping and lining into a single machine?

Combining tamping and lining into a single machine saves time and resources, as it allows for both functions to be performed in one pass over the track, improving efficiency in track maintenance.

Outlines

00:00

🚂 Introduction to Heavy Railway Machinery

This paragraph introduces the topic of the video, which is heavy railway machinery. The narrator acknowledges the complexity of the railway system and the challenges in covering all its aspects. The video aims to explore this machinery, which might be unfamiliar to many, especially those not in the railway industry. The narrator also suggests watching a previous video for better understanding of the railway track elements and explains the evolution of railway track construction technology, emphasizing the shift from manual labor to mechanized operations for efficiency and reduced manpower.

05:04

🛠️ Machines for Railway Track Laying and Construction

This paragraph delves into the machines used for laying railway tracks. It discusses the development of track construction technology and the two primary methods of track-laying, both of which require earthworks to be completed first. The track formation serves as a stable foundation for the sub-ballast and ballast layers, which are crucial for track performance and maintenance. The video explains the process of laying ballast and the division in track-laying approaches, highlighting the use of specialized machinery for laying sleepers and rails either separately or together. The description of the machinery includes the role of caterpillars, control operations, self-propelled gantries, and conveyor systems in efficiently placing sleepers and rails.

10:08

🛠️ Machines for Railway Track Renewal

This paragraph focuses on the machinery used for railway track renewal, which is more complex than track-laying machines. It covers the stages of track renewal, starting with the removal of old sleepers and the release of rail fastening systems. The machinery involved in this process includes devices for untying rails from sleepers, lifting old rails, and inserting new ones. The video also describes the process of clearing the ballast bed, laying new concrete sleepers, and the use of automatic track copying to match the original geometry of the old tracks. The paragraph concludes with a discussion on the final steps of track renewal, including the use of ballast handling units and the importance of tamping and leveling the track.

🛠️ Ballast Tamping and Cleaning Machines

This paragraph discusses the purpose and function of ballast tamping and cleaning machines in the railway maintenance process. The tamping machine is described as a device that packs the ballast under railway tracks to enhance the durability of the superstructure and substructure. It also corrects the alignment of the rails for a smoother train ride and reduced mechanical strain. The paragraph explains the process of tamping, including lifting and lining the rail and sleepers, and the use of vibrating tines to compact the ballast. The ballast cleaning machine is highlighted as a specialized tool for cleaning the railway track ballast, removing worn ballast and replacing it with new material to maintain track stability and drainage. The video concludes by thanking the viewers and patrons for their support and encouraging them to engage with the channel.

Keywords

💡Railway System

The railway system refers to the complex network of tracks, trains, and infrastructure that facilitate rail transport. In the video, it is highlighted as multidimensional, indicating its vastness and complexity, which includes various aspects such as construction, maintenance, and operation of railways.

💡Heavy Railway Machinery

Heavy railway machinery encompasses the large, specialized equipment used in the construction, maintenance, and renewal of railway tracks. The video discusses these machines as essential tools that have evolved with the growth of railway traffic and the need for efficiency and reduced manpower.

💡Track Formation

Track formation is the platform, including the sub-ballast and ballast layers, upon which the track superstructure is built. It serves as a stable foundation and is crucial for rail track performance and maintenance. The script mentions that earthworks are completed first to establish this formation.

💡Ballast

Ballast is the crushed stone material used to support the sleepers and keep the rails in place. The script explains the process of laying the ballast in the bottom layer and its importance in forming a solid track foundation.

💡Sleepers

Sleepers, also known as ties, are the rectangular or wooden blocks that support the rails. The script describes how sleepers can be laid first and then rails fastened to them, or laid together with rails as a track grid.

💡Track Laying Machine

A track laying machine is a specialized piece of equipment used to lay down railway tracks efficiently. The video describes its components, such as the caterpillar, main control operation, and self-propelled gantry, and how it places sleepers and rails onto the ballast layer.

💡Thermite Welding

Thermite welding is a method used to join rail sections together, especially for high-speed railways. The script mentions this method as an alternative to fish plates and bolts, creating a continuous welded rail for better track performance.

💡Track Renewal Machine

A track renewal machine is used to replace old or worn-out railway tracks with new ones. The video details the stages of track renewal, including the removal of old sleepers, insertion of new rails, and the preparation of the ballast bed for new sleepers.

💡Ballast Tamping Machine

A ballast tamping machine is used to compact the ballast under the railway tracks, ensuring a stable and durable track structure. The script explains how this machine corrects the alignment of rails and packs the ballast to maintain the track's integrity.

💡Ballast Cleaning Machine

A ballast cleaning machine specializes in cleaning and maintaining the railway track ballast. The video describes how it removes worn ballast, screens it, and replaces it with new material to improve track drainage and flexibility.

💡Continuous Welded Rail

Continuous welded rail refers to the practice of welding together rails to form a single, unbroken length that can be several kilometers long. The script mentions this as a modern method used in railways to enhance track stability and reduce maintenance.

Highlights

Railway systems are multidimensional and complex, with no single expert capable of knowing all aspects.

Heavy railway machinery can be surprising to those not familiar with the industry.

The development of railway equipment and specialized machinery has been driven by increased traffic density, train speeds, and safety requirements.

Railway track construction technology has evolved with continuous-action and assembly-line methods for efficiency.

Two methods for track-laying involve either laying sleepers first or combining sleepers and rails into a track grid.

Track construction machines feature caterpillar systems, control operations, and self-propelled gantries for efficient sleeper and rail placement.

Pre-assembled rail and sleeper sections can be installed using machines with jib cranes for simplified logistics.

The top ballast is crucial for forming a solid track foundation and involves a series of processes including unloading, spreading, lifting, lining, and tamping.

Modern railways often use continuous welded rail to create long, uninterrupted sections for improved performance.

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Railway track renewal machines are complex, integrating multiple units for a stage-by-stage renewal process.

Old sleepers and rails are removed, and new ones are inserted using machinery designed for efficient track renewal.

Ballast excavating and cleaning processes are part of track renewal, with some machines able to screen and reuse old materials.

Automatic track copying ensures new sleepers and rails match the original geometry for consistent performance.

Ballast tamping machines are essential for maintaining the durability and service life of the track superstructure and substructure.

Some modern tamping machines also correct rail alignment for a smoother train ride and reduced mechanical strain.

Ballast cleaning machines specialize in restoring the effectiveness of ballast by removing worn materials and replacing them with fresh ones.

The Railways Explained channel provides educational content for rail enthusiasts and professionals alike.

Transcripts

Hello guys.

Welcome back to Railways Explained.

In today s video, we are taking deep dive into something which, to be honest, to some

extent was not well known even to us.

If you closely follow our work, you might already guess that the railway system is so

multidimensional that there is no expert in the world capable of knowing all its aspects.

Anyway, as we decided to break the rules of physics and to cover all possible railway

topics, we decided to give it a try.

Today we are talking about the heavy railway machinery, which might knock you off the chair

in case you are not from the railway industry.

Of course, we will not cover all such machines, at least today, but in the future, who knows.

Before we proceed, one disclaimer.

If you are not familiar with the elements of the railway track, it might be a bit difficult

for you to fully understand this video.

So, we recommend first watching our old video What are the Purpose and Elements of the Railway

Track?

Now, like everything else at the beginning, the railway lines were built manually with

simple equipment, tools and construction technology.

The same was true for maintenance.

But as traffic density, train speeds, loading, safety requirements, and demand for railways

grew, so did the development of equipment and specialized machinery that enabled these

activities to be conducted efficiently and with reduced manpower.

As you ll see these machines are characterized by continuous-action and an assembly-line

method within a mechanized operation which has proven to be the most cost-efficient.

Let's start with the first machine.

Machines for railway track laying

The railway track manufacturing is fast developing these years, as well as the railway track

construction technology.

The process of building railway tracks has evolved in the late years.

There are two methods for track-laying, both having in common that earthworks are completed

first, thus establishing track formation.

The track formation is the platform upon which the track superstructure is constructed.

Its main function is to be a stable foundation for the sub-ballast and ballast layers.

This is a very important component, which has a significant impact on rail track performance

and maintenance.

The next step is laying the ballast in the bottom layer, mainly the ballast belt in the

area below the two rails.

After this step, there is a division in the track laying approach.

When the railway lines were built manually, the sleepers were laid first and then rails

were fastened to the sleepers.

And according to that technology, the special machine was invented.

However, sleepers and rails can be laid together at one time if the rails and sleepers are

combined previously, forming the track grid.

In case the sleepers and tracks are laid separately, one typical track construction machine is

composed of a caterpillar, the main control operation, and a self-propelled gantry.

In this case, the new rails were previously positioned along the sides of the track formation

that threaded to the rails guides located at the front of the track laying machine.

The self-propelled gantry keeps sleepers supplied to conveyor systems.

The gantry moves to the sleeper receiving conveyor, deposits the sleeper and returns

to the sleeper supply car for another load.

After being deposited by the gantry, the sleepers move by a conveyor system through the sleepers

drop area.

The sleepers are discharged from the sleeper placement mechanism and are precisely spaced

on the ballast layer to the exact position required by the specification.

After the rail passes through the rail guides, it is guided into a gauging station.

The final placing of the rail to the sleepers is controlled by an operator who guides the

rail onto the sleeper seat.

At this time, there will be workers operating equipment to fasten the rail fasteners, so

that the rail is fixed to the sleeper seat.

Another way of railway track installation is laying rails pre-assembled with sleepers.

Sections of rails and sleepers are placed together in advance at the logistic area.

This machine has a simple structure with a jib crane that lifts the assembled rails down

to the ballast.

After one section is finished, another lift begins to connect the two parts of the rails.

As we stated before, only the bottom ballast has been laid.

The top ballast is needed to form a solid track foundation.

The procedure mainly includes ballast unloading, ballast spreading, track lifting, track lining,

and tamping.

After track laying and ballasting, the rail sections need to be fixed to form a stable

line.

Fish plate and fish bolts are usually used to connect rail sections of ordinary railways.

For high-speed railways, the thermite welding method is usually used to link rail sections.

Most modern railways utilize continuous welded rail where rails are welded together to make

a single continuous rail that might be a few km long.

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Machines for railway track renewal

The railway track renewal machine is even more complex than the previous.

Namely, this machine also contains additional units of machinery and materials required

for track renewal.

All these units are combined into one fantastic machine that moving forward allows the track

renewal process stage by stage.

The first stage of track renewal is the removal of old sleepers.

The releasing rail fastening system from the sleepers may be part of this process.

Some machines integrate the devices to allow machine operators to manually position the

device to each clip and trigger it to automatically release the clip or automatically remove spikes

in the older type of wooden sleepers.

After the rails are untied from the sleepers, those old rails will be lifted and pushed

towards the sides of the train.

The new rails are also fed in near the sides of the machine in preparation to be inserted.

The track renewal machine is equipped with a device that pulls the old sleepers out from

the ballast.

These old sleepers are delivered into the conveyors to move them out for storage at

the rear of the train.

The ballast bed is then cleared in preparation for laying new concrete sleepers.

In case there is a need to lower the ballast bed the ballast excavating process will be

done.

This feature is integrated only in some models of the track renewal machines.

Excess ballast in that case will be moved out through the conveyor belt to the ballast

storage area.

Those old ballast materials will be screened and cleaned to be reused.

The unusable ballast will be kept in separate storage to be discarded.

Some machines have an automatic track copying.

It is done by recording the track geometry of the old rails prior to the removal, and

then calculating the exact amount to clear the ballast bed, to prepare for laying new

sleepers and rails to match the original geometry of the old ones.

This is followed by a new sleeper laying.

This machine has gantry cranes attached to the top of the machine that are used to transport

old sleepers into the storage area and bring the new ones into the working area.

The new sleepers are delivered by the cranes to feed into the machine.

The machine puts sleepers onto the ballast bed and spaces them to the exact position

required by specification.

After the new sleepers are laid, the new rails will be pushed from the side of the machine

into position on the sleepers.

After the track renewal machine completes the tasks, the ballast will be put back on

the track.

Some track renewal train units have the ballast handling included such that the entire process

of shoulder cutting, cleaning and placing of ballast is fully integrated.

For track renewal machines that do not have ballast excavating machines included, workers

will use a shoulder ballast cleaner machine.

For track renewal machine that do not include track copying or leveling, a ballast tamping

machine will be used to make final adjustments to the track to the correct specification.

Ok, if you survived watching the video this long, it only can mean that you are nothing

but a real rail lover!

Hold your seats, we are jumping to the ballast cleaner and ballast tamping machine.

Ballast Tamping machine

The purpose of ballast tamping machine is to tamp or pack the ballast under railway

tracks.

It is done to make the superstructure and substructure more durable in terms of the

service life.

Prior to the introduction of mechanical tampers, this task was done by manual labour with the

help of beaters.

At its most basic level, a tamping machine only packs the ballast according to the parameters

defined by regulation.

Some modern machines, sometimes known as tamper-liners or tamping and lining machines, also correct

the alignment of the rails to make them parallel and level, in order to achieve a more comfortable

ride for trains and to reduce the mechanical strain applied to the rails by passing trains.

This is done by finding places where the sleepers have sunk from the weight of the passing trains

or frost action, causing the track to sag.

The tamper lifts each sleeper and the rails up, and packs ballast underneath.

When the sleeper is laid down again, the sagged rails now sit at the proper level.

Combining tamping and lining into a single machine saves time and money, as only one

machine needs to be run over the track to perform both functions.

Tamper machines are built in many different varieties depending on their purpose.

Plain line tamping machines are used on line sections which have no points or other complex

track structures, while switch tamping machines are used to tamp switches, crossings and other

complex track structures.

The tamping process from any type of tamper consists of the following basic steps.

The lifting, lining unit moves the rail and sleepers under the tamping unit into the desired

vertical and horizontal position.

At this stage, the desired position of the rails and sleeper will only be maintained

as long as the lifting, lining unit holds the track in position.

The tamping units drive vibrating and oscillating tines of optimum 35 Hz into the ballast on

both sides of the sleeper parallel to the rails until squeezing depth is achieved.

The rapidly vibrating and oscillating tines in effect liquefy the ballast to allow easy

insertion of the tines.

The vibrating tines are pushed together underneath the sleeper to pack ballast underneath the

sleeper being held in position by the lifting, lining unit to ensure it holds position when

released by the lifting, lining unit.

The tamping unit retracts to the rest position, slightly above the top of the rails.

The track and sleeper are released by the lifting, lining unit and maintain their position

thanks to the modification of the ballast done in the previous step of the process.

Then the tamping machine moves to the next sleeper and begins a new cycle.

Ballast Cleaning machine

Ballast cleaning machine is a machine that specialises in cleaning the railway track ballast.

Why there is a need for ballast cleaning?

Over time, ballast becomes worn, and loses its angularity, becoming rounded.

This hinders the tessellation of pieces of ballast with one another, and thus reduces

its effectiveness.

Fine pieces of granite, like sand, are also created by attrition, known simply as "fines".

Combined with water in the ballast, these fines stick together, making the ballast like

a lump of concrete.

This hinders both track drainage and the flexibility of the ballast to constrain the track as it

moves under traffic.

This machine removes this worn ballast, screens it and replaces the "dirty" worn ballast with

new and fresh.

Ballast cleaning machine use a cutter bar that runs beneath sleeper level excavating

all of the ballast under the sleepers to a specified, variable depth.

A conveyor then moves the ballast into the cleaner, where it gets forced through a mesh

by a shaking chamber.

Ballast stones which are smaller than the mesh size fall through and are removed, while

those that are bigger than the mesh are returned to the track along with new ballast.

Some ballast cleaners have both ballast and spoil wagons attached to it, to which the

materials are fed by a series of conveyor belts.

Others simply undercut the ballast, and allow for a work train to come through to dump fresh

ballast.

After the track has been filled with cleaned ballast, the ballast is compacted around the

sleeper ends.

This achieves an immediate fixation of the track grid in the cleaned ballast bed.

You were watching the story of amazing heavy railway machinery on Railways Explained.

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Until the next time, goodbye!