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Hydrauilics, Irrigation

Controlled Flooding- 6 Types| Free Flooding| Basin Flooding

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Types of flooding is an important topic in irrigation engineering, but they are usually classified based on the irrigation method rather than flooding itself. It’s mainly divided into three. Surface irrigation where water flows directly over the soil including basin flooding, furrow and border techniques.In subsurface irrigation water is delivered below the soil surface via tubes, minimizing evaporation. In case of sprinkler irrigation pipes and sprinklers are used to distribute water like rainfall.

In this blog, we will delve deep into the different types of controlled flooding in irrigation, exploring methods such as Free flooding, basin flooding, flooding by contour laterals, zigzag method of flooding, border strip flooding and check flooding are the 6 types of controlled flooding which is a subcategory of surface irrigation.

We will examine how these techniques manage water efficiently, their advantages, and their impact on agriculture and the environment.

What is Controlled Flooding Method of Irrigation

In controlled flooding, water is spread or flooded on a rather smooth flat land, without much control or prior preparation. This method is generally used in the inundation irrigation system in which water is forced to spread over vast tracts during the season of high streamflow.

It is a wasteful use of water and is practised largely where irrigation water is abundant and inexpensive.

Controlled flooding techniques in irrigation, including the flooding method of irrigation, optimize water use and minimize damage. Unlike traditional flooding irrigation, which can lead to inefficient water use, controlled flooding carefully manages water levels to enhance efficiency. Techniques such as free flooding, where water spreads broadly, and wild flooding, which lacks control, are contrasted with more precise methods like the check basin method. The check basin method uses barriers to contain and direct water, reducing runoff and erosion. Controlled flooding not only improves water distribution but also conserves resources and enhances crop yields. By managing water flow more effectively, these techniques address the challenges of traditional flooding, ensuring better agricultural outcomes and environmental sustainability.

Types of Controlled Flooding Irrigation


Controlled flooding irrigation includes several methods to manage water levels efficiently. These techniques aim to improve water distribution and reduce waste. let’s peep into the hierarchy of methods of controlled irrigation.

  • Free Flooding irrigation/wild flooding irrigation
  • Contour Lateral Flooding
  • Border Strips Flooding irrigation
  • Checks basin Flooding
  • Basin Flooding
  • Zigzag Method of Flooding
Methods of Controlled Flooding

Free flooding or flooding from field channels

Free Flooding

Free flooding method consists of dividing the entire land to be irrigated into small strips by a number of field channels known as laterals.

  • These laterals may be either at right angles to the sides of the field, or at right angles to the contour lines as shown in figures.
  • When the laterals are aligned at right angles to the sides of the lateral, irrigation is possible only to one side of the lateral. However, when the laterals are aligned at right angles to the contours, irrigation is done to both the sides of the lateral.
  • The field channels receive water from the supply channel and discharge excess water in the waste channel.
  • Water is applied to the strip of a land through feeding points provided at some interval along the laterals.
  • This method of water application can be used both for flat lands as well as for relatively steep lands. The alignment and spacing of the laterals depends upon the type of soil and topography of land.
  • If the slopes are steeper, the closer spacing of laterals is required. Similarly, closer spacing is required for relatively more permeable soils.
  • For flat land and for relatively less pervious soils, the spacing of the laterals may be increased. Normally the spacing of the laterals may vary from 10 to 50 metres.
  • However, the method is more suited for irrigation fields containing medium type soil and having slopes ranging from 1 in 100 to 1 in 300.

Let’s find out about the next method of controlled flooding.

Flooding by contour laterals

Flooding by Contour Laterals

This is a special case of free flooding in which the field channels or laterals are aligned approximately along the contour lines.

This method is applicable to steeper terrain.

The field is cut by a relatively dense network of small contour laterals, the spacing of which depends upon the prominent grade of field between two adjacent ditches or laterals, the uniformity of slope and the soil type.

I have explained the details of border strip flooding and checks basin flooding in previous blogs. So, let’s move on to the next member.

ALSO READ: Rainwater Harvesting Methods: Everything You Need To Know

Border Strips Flooding irrigation

The border strip method, also known as border strip flooding irrigation, involves dividing a field into strips, typically 10 to 20 meters wide and 100 to 300 meters long, separated by low levees or borders. Water is directed from a supply ditch to the head of each strip, flowing down the slope in a controlled sheet, guided by the borders. The surface between the borders is kept level to ensure uniform coverage. Slopes vary from 0.2% to 0.8% along the strip, with cross slopes minimized to prevent uneven irrigation. This method is efficient for forage crops and requires minimal investment and labor. The length of each strip is adjusted based on soil type, infiltration rate, and irrigation stream size. For example, sandy soils typically use shorter strips, while clay soils may use longer ones.

Basin Flooding

Basin Flooding
Basin Flooding

The ring basin flooding is a special form of check basin flooding adapted to orchards.

  • Ring basins are formed for each tree; in some cases, one ring basin may be formed for two or more trees.
  • Water is supplied to these basins through a supply ditch. In some cases, a number of ring basins are interconnected.
  • Portable pipes or large hoses may also be used in place of ditches.

Last, but not the least let me explain about final method of controlled flooding.

Zigzag method of controlled flooding

Zig Zag Method of Flooding
Zig Zag Method of Flooding

It is special method of flooding where water takes circuitous route before reaching the dead end of each plot.

  • The whole area is divided into a number of square or rectangular plots; each plot is then subdivided with the help of low bunds or levees.
  • This method is suitable for relatively level plots. It is, however, highly unsuitable for farming operations with modern farm machinery.

That’s it about the methods of controlled flooding.

MUST-READ: Concept of green building- 4 comprehensive concepts easy read!

I hope you got a fair idea about free flooding, basin flooding, flooding by contour laterals and zigzag method of flooding.

Happy learning!

Intelligent transportation system, TRANSPORTATION ENGINEERING

Electronic toll collection- 4 subsystems full details

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Electronic toll collection is one of the best advancements of Intelligent transportation system in transportation sector. We will see what is electronic toll collection in the next section. Later, I will walk you through four subsystems of ETC. They are automatic vehicle classification (AVC), violation enforcement system (VES), automatic vehicle identification (AVI) and transaction processing, which includes a back office and customer service center. The advantages, cost and disadvantages of ETC will also be discussed.

Moving onto the definition,

What is Electronic Toll Collection?

Electronic toll collection is a wireless system to automatically collect the usage fee or toll charged to vehicles using toll roads, HOV lanes, toll_bridges, and toll_tunnels.

Typical methods for collecting tolls are,

  • Manual collection
  • Automatic toll collection via coin machines
  • Electronic toll collection (ETC)

Manual toll collection is the simplest form of toll collection, in which a collector operating from a booth collects the toll.

Automatic coin machines allow collection of several methods of payments such as coins, tokens, smart cards, and credit cards without the need for a collector.

ETC is the most complex and latest method for collecting tolls. Although it has been in use for more than 20 years, ETC continues to evolve. ETC lanes improve the speed and efficiency of traffic flow and save drivers’ time.

An ETC system is capable of electronically charging a toll to an established customer account.

The system can determine whether a passing car is registered, automatically charging those vehicles, and alert the local highway patrol about users that are not registered. The ETC method allows vehicles to pass through a toll facility without requiring any action or stopping by the driver.

Now let’s see the advantages of electronic toll collection system.

Advantages of Electronic Toll Collection System

Systematic vehicle parking- an application of ITS like electronic toll collection
Systematic vehicle parking- an application of ITS like electronic toll collection
  • Typical ETC systems can improve the traffic flow through the toll area. Manual toll collection lanes handle about 350 vehicles per hour and automatic coin machine lanes handle about 500 vehicles in the same time period.
  • An ETC lane can process 1,200 vehicles per hour when the lane is located in a traditional plaza configuration with island structures on each side of the lane and up to 1,800 vehicles per hour in all-electronic tolling (AET) configurations.
  • An AET lane offers over five times the flow rate of a manual lane and nearly four times the flow of an automatic coin machine lane.
  • Most ETC lanes are less expensive to build and operate than traditional toll collection methods.
  • Cost data averaged for five toll facilities in five states showed electronic toll collection systems provide cost savings of over $40,000 per lane for equipment costs, and $40,000 per lane in annual operating and maintenance costs compared with automatic coin machines, and $135,000 per lane in annual operating and maintenance costs compared with manual tollbooths.
  • ETC lane usage can decrease emissions in the area.
  • Practitioners have reported that the ETC system at three toll plazas in Baltimore, Maryland, with dedicated ETC lanes located in a traditional plaza configuration with island structures on each side of the lane resulted in a 40 to 63 percent reduction of hydrocarbon and carbon monoxide, and approximately 16 percent reduction of nitrogen oxide in the study area.

That’s it about the advantages. Its time to see the principles of electronic toll collection.

Don’t miss out Google position 1st post: Road margins- 6 types of road margins in highway

Principles of Electronic Toll Collection

Typical ETC systems are comprised of four subsystems

  • Automatic vehicle classification (AVC)
  • Violation enforcement system (VES)
  • Automatic vehicle identification (AVI)
  • Transaction processing, which includes a back office and customer service center.

Automatic Vehicle Classification

  •  Automatic Vehicle Classification (AVC) consist of sensors installed in the toll lanes to detect and classify the vehicles for proper tolling.
  • The AVC technique is most commonly performed using overhead equipment (laser or infrared detectors) or intelligent detector loops embedded in the pavement, but the detectors can also be placed on the roadside.
  • The sensors are capable of perceiving and classifying vehicles in the open road tolling or all electronic tolling environments.

Violation Enforcement System

  • The primary goal of Violation Enforcement System is to reduce the number of toll evaders with the assistance of multiple types of solutions.
  • These methods range from fairly basic (audible and/or visual alarms) to complex systems, such as automatic license plate recognition camera-based solutions.
  • Police enforcement and toll gates are other types of successful VES but can be costly and inefficient for high traffic volumes.
  • Camera-based VES captures images of each vehicle’s front and/or rear license plates, depending on the toll authority’s regulations.
  • The necessary equipment consists of a camera (or array of cameras), an illumination system, and a controller card or computer that interfaces with the lane controller and/or the back office.
  • A camera-based VES with plate recognition serves a dual purpose of enforcement and video tolling.

Automatic Vehicle Identification

  •  The Automatic Vehicle Identification systems properly identify each vehicle to charge the toll to a particular customer.
  • This ETC method is typically done with various AVI technologies such as a bar coded label affixed to the vehicle, proximity card, radio or infrared transponder, and automatic license plate recognition.
  • A majority of the AVI systems used involve radio frequency identity (RFID) and plate recognition technologies.
  • The RFID system uses an antenna to communicate with a transponder in each registered vehicle, while video tolling identifies the license plate and charges a customer or sends a bill to unregistered drivers with help from the Department of Motor Vehicle’s address database.

Transaction Processing with Back Office and Customer Service

  • The back office consists of the host and/or plaza system, customer service center, and violation processing center.
  • The main functions of the host and plaza systems are to aggregate transactional data from all the lanes, data summarization, report generation, download of files such as a toll rates, toll schedules, and transponder status list.
  • The customer service center is responsible for processing the AVI and video tolling transactions, matching transactions with account holders, debiting the correct toll amount, managing accounts, generating a valid tag list, and providing customer support to name a few.
  • The violation processing center’s main function is to process the images of the licenses plates, identify violators, and mail notices.

 We have seen all the positives till now. Any topic is incomplete without raising the negative side. I will tell you that now.

Also read: Gauges in railway- All Details About Broad, Metre and Narrow Gauges

Disadvantages of Electronic Toll Collection System

Charging a car- an application of ITS like electronic toll collection
Charging a car- an application of ITS like electronic toll collection

Most of the technological issues have been overcome after two decades of successful ETC implementations. The current issues with implementing ETC systems are related to interoperability and technology selection.

  • There is a lack of interoperability with other states and with toll facilities at border crossings.
  • The need for interoperability between border crossings and toll roads will continue to increase as toll road are built near the border.
  • Technology selection directly impacts interoperability. If a toll agency selects a different RFID protocol then it might not be able to read customers from away agencies.
  • Cities and local toll authorities should work together to create a compatible system throughout the state.

And finally, we have reached at the practical aspect.

Cost of ETC

  • The cost of implementing an ETC system varies widely depending on the scope of the project, making it difficult to provide an exact cost.
  • The system size (number of lanes and collection points), shoulder coverage, gantry type, and type of technology all affect the project price.
  • The cost is also affected by whether the system is new, upgraded, or added onto.
  • The price range will change based on the level of customized software required for the business rules, the back office operation (outsource or in-house), the project location, and the necessary signage.
  • The cost per ETC lane in an AET or ORT environment ranges from $100,000 to $200,000 for the cost of the lane equipment and its installation, and assuming the project reuses existing back office software, gantry, and right of-way.

MUST READ: Bitumen for road- Grade and properties of bitumen

Hope the article benefited you. So, electronic toll collection is an amazing tool, right? Let me know that in the comments.

Enjoy learning!

Hydrauilics, Irrigation

Check flooding and Border strip methods of irrigation| Types of surface irrigation

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Check flooding and border strip method are two types in surface irrigation, one of the major methods of irrigation. In the blog, we are going to learn everything about these two with figures.

Before we begin, let’s look at the classification of surface irrigation. Check flooding and border strip method are two that comes in the bottom. I will surely cover other main categories in another blog.

We saw the hierarchy of methods of surface irrigation. Let’s jump right into the first method which is border strip method.

Figure shows methods of irrigation

Border strip method in detail

The diagram below shows border strip method.

Figure shows border strip method
Diagram showing border strip method

Border strip method is otherwise called border strip flooding method. The main points regarding this are,

In the border strip flooding method, the farm is divided into a series of strips 10 to 20 metres wide and 100 to 300 metres long.

These strips are separated by low levees or borders and run down the predominant or any other desired slope.

To irrigate, water is turned from the supply ditch onto the head of the border. Water advances confined and guided by two borders in a thin sheet towards the lower end of the strip.

The surface is essentially level between two borders so that the advancing sheet of water covers the entire width of the strip.

The lengthwise slope varies from 0.2 to 0.8 %. The border strip should be level cross wise.

Cross slopes within border strips cause water to concentrate along the lower side of the strip causing uneven irrigation.

This method is especially suited to forage crops,its advantage being that for a relatively low investment a system can be developed which can afford the highest irrigation efficiency and lowest labour requirements.

With highly mechanised farming, large area can be irrigated within a short time by border strip method. The length of border strip depends upon how quickly it can be wetted over its entire length. This depends upon,

  • Infiltration rate of the soil
  • Longitudinal slope of the land
  • Size of irrigation stream available

The following lengths are suggested for moderate condition

Type of soil of border stripLength
Sandy soil or sandy loam   60- 90m
Medium silt loam90-150
Clay loam or clay soil  150- 300
Length of border strip with type of soil

The first 6 to 12m length of the strip should be made level to ensure uniform spreading of water. Water is diverted to the border strips from the following

Warth or concrete ditches

These run at a flat longitudinal grade. The water is discharged into the strips via border gates, aluminum syphons or plastic piping

Underground concrete pipes through risers

In this method, water is let into the strips by concrete risers

That’s it about border strip method. Let me walk you through check flooding now.

Also read: Concept of Green Building- 4 comprehensive concepts easy read!

Check flooding

The diagram given below shows check flooding.

Figure shows check flooding
Check flooding

The method is also known as irrigation by plots since the entire area is divided into several plots obtained by subdividing the entire area by levees

Moving on to the main details,

  • Check flooding is similar to free flooding except that the water is controlled by surrounding the check area with low, flat levees surrounding each check while in free flooding no such levees are provided and the strips are divided by field channels.
  • Each plot is practically level. The size of levee depends upon the depth of water to be applies as well as the stability of the soil when it is wet.
  • Water is conveyed to the land by a system of supply channels a swell as laterals.
  • Usually, there is one field channel for every two rows of plots. Water is admitted to these plots at the higher end and the supply is cutoff as soon as the lower part of the plot has received the sufficient depth of water.
  • Oblong plots are preferred to the square plots. The size of the plots depends on the porosity of the soil.
  • In a levelled ground, the plots are generally rectangular, but if the ground has same initial slope, the checks or levees may follow contours.
  • Contour checks are prepared by constructing ridges along contours at vertical intervals of 6 to 12 cm and connecting them with cross ridges at intervals.
  • Very little crop land is perfectly level, and the water does not stand at a uniform depth over the entire check. This results in uneven distribution of water within the plot.
  • Low area will receive too much water and high gets too little. 
  • The size of check basins is dependent on the infiltration rate. It may vary from 1m2 for growing vegetables and other intensive irrigation to 1- 2 hectares for growing rice under wet land conditions.
  • However, the more common size varies from 0.03 to 0.06 hectares for medium soils. The size of stream should be sufficient to cover the entire basin in a relatively small portion of time required

So, that was the main details on check flooding.

Also read: Innovative Water Conservation Methods Unlocked.

What are your thoughts on border strip method and check flooding? Let me know that in the comments.

Hydrauilics, Irrigation

Methods of Irrigation- 3 Methods Full Guide

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Methods of irrigation is an important portion in hydraulics. There are mainly three methods- surface irrigation, subsurface irrigation and sprinkler irrigation. Subsurface irrigation is again divided into natural sub-irrigation and artificial sub-irrigation.

Before selecting a particular method, the irrigation engineer must evaluate all the factors, and choose that method which is best suited to the local conditions.

Basic requirements for adaptation of irrigation methods

  • The method should be such that uniform water distribution with as small as 6cm water depth applications can be made for light irrigation
  • At the same time, it should afford a heavy uniform application of 15 to 20 cm water depth.
  • It should allow the use of large concentrated water flows for reduction of conveyance losses, and labour cost.
  • It should be suitable for use with economical conveyance structure.
  • It should be such that mechanized farming is facilitated

Good irrigation method results in increased yield and conservation of resources with soil productivity maintained and water utilised economically. Over irrigation results in soil erosion, leached fertilizers, drainage troubles and salt accumulation.

Basic methods of Irrigation

Water may be applied to the crops by through three basic methods of irrigation.

  • Surface irrigation method
  • Subsurface irrigation method
  • Sprinkler irrigation method

Let’s dive into through each of them now.

Also read: Concept of Green Building- 4 comprehensive concepts easy read!

Surface irrigation method- Largest among methods of irrigation

Surface irrigation is a method of irrigation where water is applied and distributed over the soil surface due to gravity. It is the most common form of irrigation throughout the world and has been practised in many areas.

Surface irrigation is also known as flood irrigation, which means that water distribution is uncontrolled. So, it will be inefficient. Some of the irrigation practices grouped under this name involve a large degree of management. Surface irrigation is mainly of three types.

  1. Flooding method
  2. Furrow method
  3. Contour farming
Surface Irrigation classification

We shall discuss about each of the subdivisions in another blog. Now, come with me to shake hands with subsurface irrigation.

Subsurface irrigation method

The sub surface irrigation method consists of  supplying water firectly to the root zone of the crop. The favourable conditions for the sub surfacr irrigation practice are

  1. Impervious sub soil at reasonable depth (2 to 3m) or existence of high water table
  2. Permeable soil such as loam or sandy loam in the root zone of the soil
  3. Uniform topographic conditions
  4. Moderate slopes
  5. Good quality irrigation water

If all these favourable conditions are fulfilled and if proper precautions are taken to prevent alkali accumulation or excess water logging, the method results in exonomical use of water, high crop yield and low labour cost in preparing the irrigation plots.

Subsurface irrigation may be of two classes

  1. Naural sub irrigation
  2. Artificial sub irrigation
Sub surface Irrigation classification

Also read: LEED certification India- a comprehensive guide

Next, let’s know more details about these methods of irrigation shown in the diagram.

1. Natural sub irrigation

In natural sub irrigation, water is supplied to the root zone of the plants by controlling the level of local water table, such a high level of water table in the area may be available due to water seeping from earthen canals, drains, rivers, etc.

The main points in natural sub irrigation are,

  • In order to ensure the requisite supply of water to the root zone, its is essential to maintain the desired water level by artificial means.
  • For this purpose, water is supplied to a series of ditches half to one metre deep and 25 to 50cm wide having vertical sides.
  • These ditches are spaced from 15 to 100m apart depending upon the Permeability_of_sub soil and topography of land.
  • The depth of ditches may vary from 0.3 to 0.5m These channels have relatively flat slopes.
  • Water flows at a slow rate and seeps into the ground to maintain the water table at a height such that water from the capiliary fringe is available to the vrops.
  • Proper drainage of excess water is permitted, either naturally or with the other drainage works to prevent water logging of the fields.
  • Sometimes the upward capiliary water flow from shallow water table may produce saline and alkali conditions and may make the land less productive.
  • Under such circumstances, the subsurface irrigation method has to be discontinued and irrigation has to be resorted by sprinkling method.

Next member is artificial sub irrigation method. What are we waiting for? Let me give you more details on that.

2. Artificial sub irrigation

The artificial sub irrigation method consists of supplying water diretly to the root zone of crops through a network of buried perforated pipes. Water is made to pass under pressure, through these underground perforated pipes.

This method is suitable only for those soils formations which have high horizontal permeability to permit free lateral movement though the root zone of the crops and low vertical permeability so that deep percolation losses are minimised.

The pipe are buried 0.3 to 0.4m deep, so that cultivation operations are not hindered, an are spaced  0.4 to 0.5m horizontally, for uniform distribution of water.

Also read: Vastu for home plan- all design tips backed by logic

Its time to meet the last member, sprinkler irrigation.

Sprinkler irrigation

figure shows sprinkler irrigation
Sprinkler Irrigation

The sprinkler irrigation method consists of applying the water in the form of a spray, somewhat as in ordinary rain, as is done in the garden lawn sprinkling.

The greatest advantage of sprinkler irrigation is its adaptabilities to use under conditions where surface irrigatin methods are not efficient. The method is more useful where,

  1. The land cannot be prepared for surface methods
  2. Slopes are excessive
  3. Topography is irregular
  4. Soil is erosive
  5. Soil is excessively permeable or impermeable
  6. Depth of soil is hallow over gravel or sand

In this system, the cost of land preparations and permanent water delivery system of channels or conduits is less. However, there is large initaial investment in the purchace of the pumping and sprinkling equipment.

Sprinkler system can be classified under 3 heads.

  1. Permanent system
  2. Semi-permanent system
  3. Portable system
Sprinkler Irrigation Classification

Earlier, stationary overhead perforated pipe installations were used. However, with the introduction of lightweight steel pipes and quick couplers, a portable sprinkler system was developed.

In the permanent system, pipes are permanently buried in such a way that they do not interfere with tillage operations.

In the semi-permanent system, the main lines are buried while the laterals are portable. A portable system has both portable mains lines and laterals. These systems are designed to be moved from around the farm from field to field.

A pump usually lifts the water from the source, pushes it through the distribution system and through the sprinkler nozzle on the sprinkler heads mounted on rising pipes attached to the laterals. Turbine and horizontal centrifugal pumps are used.

So, that’s it about methods of irrigation. Was that helpful to the knowledge seeker in you?

Railway Engineering, TRANSPORTATION ENGINEERING

Coning of wheels- What is coning of wheels?

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Coning of wheels is an interesting topic in railway engineering. In this blog, we will see the theory of coming of rail wheels, starting from what is coning of wheels.

What is coning of wheels?

figure shows coning of rails
Coning of rails

Let’s see what is coning of wheels step by step.

  • The space between the inner borders of wheel rims is by and large kept less than the measurement of the track.
  • This results in a gap between the wheel rims and running ends of the rail which is approximately equal to 1cm. (2/8 on both sides).
  • More often than not, the tread of wheels is perfectly the dead centre of the beginning of the rail, since the wheel is chamfered to keep it in this middle position involuntarily.
  • Thus, in coning of wheel the tread or rim of wheels of railway vehicles is made in the shape of  a cone with the slope of about 1 in 20.
  • It maintains the vehicle in the central position with respect to the track.
  • On straight track, portions of wheels running on track have the same diameter.
  • While on the curved path, the outer wheel has to cover a larger distance than the inner wheel. Thus, the portions of wheels running on track have different diameters which help in the smooth running of wheels.

Theory of coning of wheels

Wheel rail contact geometry
Wheel rail contact geometry
  • We have seen what is coning of _wheel through some easy read bullet points. Let me do the same to learn the theory behind coning of rail wheels.
  • On a railway level track, the moment the hinge locomotes towards one rail, the wheel tread width above the rail steps-u but reduces over the other rail.
  • This forbids the auxiliary movement and hinge pulls back to its original position.
  • This is possible only if the diameters on both rails are equal and the pressure on both rails is also equal.
  • On a coiled path, because of the rigidity of the wheel bottom, either of the wheels has to slip by a measure equal to the differentiation of length.
  • Or else, the axle has to move outward a bit so that a tread with longer diameter is formed over the outer rail where, as a slighter diameter tread is formed over the inner rail.

Also read: Applications of Intelligent transportation system- everything you want to know

Calculation of coning of wheels

Behaviour of coning on curves
Behaviour of coning on curves

If the diameter of the tread on both the rails is equal, then

Slip=α (R2-R1),

The outer radius, R2=R+C/2

Inner radius, R1= R-G/2

G= Gauge

α= Angle at centre in radians

 Therefore, slip= alpha X G

α 0 = Angle center in degrees about 1 degree

α 0 Slip= 0.029 (roughly for 1 degree of central angle)

  • Therefore, the slip is about 0.029m per degree of the central angle.
  • Chamfering of wheels on bends is not useful as the principal axle if owing to centrifugal force proceeds towards the outward rail the back axle will precede towards the inside rail and the complete benefit of coning wheels cannot be availed.
  • Put differently, there will be no free sidelong movement of wheels.
  • This results in the disadvantages of the outer rail will have more pressure while the inner rail will have lesser pressure.
  • Owing to the central strength, the parallel components incline to turn the rail out and the gauge has broadening tendency.
  • Due to this condition if the voids sleepers have no base plate beneath the edge of the rail they will be damages. In order to get rid of or minimize the supra mentioned faults “angling of rails” is done.
  • When the rails are tilted then the base plate or sleeper is not placed horizontally. It is laid at a slope of 1 in 20 towards the inner side.

Advantages

  1. Smooth riding- help vehicle to negotiate curves smoothly
  2. Reduces wear and tear of wheel flanges. Damage is caused because of the friction action of rims with inner faces of the rail top.
  3. It gives an option of lateral drift of the hinge with its wheels
  4. It prevents, to some extent, the slipping of the wheels

We have seen the advantages. Let’s see the disadvantages of coning of wheels now.

Disadvantages

  1. The pressure on the horizontal component of force near the inner edge of outer rail has a tendency to wear the rail quickly
  2. The horizontal component has to turn the rail outwards and hence the gauges may be widened.
  3. If no base plates are provided, sleepers under the outer edge of the rail may be damaged

Also read: Intelligent transportation system: A comprehensive approach to its components

Railway Engineering, TRANSPORTATION ENGINEERING

Types of Gauges in railway- Broad Gauge, Metre and Narrow Gauges

5 Comments

Types of Gauges in railway is a mandatory topic to touch upon when you study railway engineering. In this article, I will take you on a journey through the three basic types of railway gauges: broad gauge, metre gauge, and narrow gauge.

  1. What is gauge in railway?
  2. Types of Gauges in railway
    1. Broad gauge
    2. Metre gauge
    3. Narrow gauge
  3. Factors affecting the choice of types of gauges in railway

What is gauge in railway?

The gauges in railway is defined as the clear minimum perpendicular distance between the inner faces of the two rails. The distance between the inner faces of a pair of wheels is called wheel gauge.

The figure below is a diagrammatic representation of gauges in railway.

diagram shows gauges in railway
Gauges in railway

Now, let’s jump right on to the various types of gauges in railway.

Some related posts from Vincivilworld

Types of Gauges in railway

There are 3 major types of gauges in railway.

  1. Broad gauge
  2. Metre gauge
  3. Narrow gauge

I will tell you more details about each of them in the upcoming sections. Let’s start with broad gauge.

Broad gauge

When the clear horizontal distance between the inner faces of two parallel rails forming a track is 1.676m, the gauge is called broad gauge. Also known as standard gauge in some countries.

Broadest gauge is used for tracks in plain areas which are densely populated for routed of maximum traffic at places which are centers of industry and commerce.

Suitability: Broad gauge is suitable under the following conditions

  • When sufficient funds are available  for the railway project
  • When the prospects of revenue are very bright

So, you got an idea about broad gauges. Let’s look into metre gauge now.

Metre gauge

Metre gauges are used when the clear horizontal distance between the inner faces of two parallel rails forming a track is 1m. It is used for tracks in under- developed areas and in interior areas where traffic intensity is small and prospects for future development are not very bright.

Suitability: Metre gauge is suitable under the following conditions;

  1. When the funds available for the railway project are inadequate
  2. When the prospects of revenue are not very bright.

That’s it about metre gauge. Next, let me give you some information about narrow gauge.

Narrow gauge

Narrow gauge is leveraged when the clear horizontal distance between the inner faces of two parallel rails forming a track is either 0.762m or 0.610m. These are used in hilly and very thinly populated areas.

Suitability: Narrow gauge is suitable under the following conditions:

  1. When the construction of a track with wider gauge is prohibited due to the provision of sharp curves, steep gradients, narrow bridges and tunnels, etc.
  2. When the prospects of revenue are not very bright.

You have seen all types of gauges in railway. Did you know the factors that should be taken into account while selecting a gauge? Its time to see that.

Factors affecting the choice of types of gauges in railway

Types of Gauges in Railway
Railway track
  1. Traffic condition: If the intensity of traffic on the track is likely to be more, a gauge wider than the standard gauge is suitable.
  2. Development of poor areas: The narrow gauges are laid in certain parts of the world to develop a poor area and thus link the poor area with the outside developed world
  3. Cost of track: The cost of railway track is directly proportional to the width of its gauge. If the fund available is not sufficient to construct a standard gauge, a metre gauge or a narrow gauge is preferred rather than to have no railways at all
  4. Speed of movement: The speed of a train is a function of the diameter of wheel which in turn is limited by the gauge. The wheel diameter is usually about 0.75 times the gauge width and thus, the speed of a train is almost proportional to the gauge. If higher speeds are to be attained, the broad gauge track is preferred to the metre gauge or narrow gauge track.
  5. Nature of country: In mountainous country, it is advisable to have a narrow gauge of the track since it is more flexible and can be laid to a smaller, radius on the curves. This is the main reason why some important railways, covering thousands of kilometres, are laid with a gauge as narrow as 610mm
  6. Gauge should be uniform and correct: Uniformity of gauge is necessary due to the following reasons:
  7. Inconvenience to the passengers while changing the train at the station, with the change of gauge:
  8. Delay in the movement of people and goods resulting in wastage of time
  9. Extra labour for unloading and reloading the goods
  10. The goods are also likely to be damaged or dislocated at the junction station, having a change of gauge.
  11. Provision of extra and costly yards, godowns, sheds, etc. At every junction station having a change of gauge. Difficulty in quick movement of military and equipment during war days.

So, you got to know everything about gauges in railways? Did I miss out anything? Let me know your thoughts in the comments.

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