Transportation engineering lecture notes: - Modes of transportation: - Human being has always remained surrounded by the three basic mediums known as land, water and air. Thus the modes of transportation are also connected with these three mediums. Land has given scope for the development of road and rail transport while water and air have developed waterways and airways respectively. Thus there are four different modes of transportation as follows: 1. Road ways / highway 2. Railways 3. Airways 4. Waterways/ sea ways 1. Roadways/ highways: It is the basic mode of transportation and the only mode which give door to door service to people and goods. It plays a very important role in the development of economy of the country. Basic need of roads arose thousands years back when only earthen roads were used for transportation only. They only increase time of the journey but also affects the comfort of the passengers and also their safety, beside the life of earthen roads was never consistent because of these problems, the concept of firm roads were develop which later on took the shape of bitumen or concrete road. Roadways do not only increase the modern highway system but also the city streets, feeder road and village roads. Every highway can be a road but every road can’t be highway. 2. Railways: - After highway it is the second most common mode of transportation and it is considered to be cheapest mode among all the movement of equal and good load is possible because of railways. It is very useful when you are travelling long distances within a country or from one country to another country. Another important advantage of railway is that if the system is manage properly there is no disturbance in the movement of train which save a lot of time and other resources, also because of railway lines are fixed the chances of accidents are minimum because the trains have only to move on the railway line.
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Transportation engineering lecture notes: -
Modes of transportation: - Human being has always remained surrounded by the
three basic mediums known as land, water and air. Thus the modes of
transportation are also connected with these three mediums. Land has given
scope for the development of road and rail transport while water and air have
developed waterways and airways respectively. Thus there are four different
modes of transportation as follows:
1. Road ways / highway
2. Railways
3. Airways
4. Waterways/ sea ways
1. Roadways/ highways: It is the basic mode of transportation and the only
mode which give door to door service to people and goods. It plays a very
important role in the development of economy of the country. Basic need
of roads arose thousands years back when only earthen roads were used
for transportation only. They only increase time of the journey but also
affects the comfort of the passengers and also their safety, beside the life
of earthen roads was never consistent because of these problems, the
concept of firm roads were develop which later on took the shape of
bitumen or concrete road. Roadways do not only increase the modern
highway system but also the city streets, feeder road and village roads.
Every highway can be a road but every road can’t be highway.
2. Railways: - After highway it is the second most common mode of
transportation and it is considered to be cheapest mode among all the
movement of equal and good load is possible because of railways. It is very
useful when you are travelling long distances within a country or from one
country to another country. Another important advantage of railway is that
if the system is manage properly there is no disturbance in the movement
of train which save a lot of time and other resources, also because of
railway lines are fixed the chances of accidents are minimum because the
trains have only to move on the railway line.
3. Airways: - In old times when air ways were not yet develop; the time of
travelling was normally very high especially when you move from one
country to another country because of the lesser speed of vehicles and
several obstructions like seas and oceans from a mountain, from protocol
of different countries etc. Therefore with the development of aero plane,
the distances were reduced to a great extent because of the higher speed
of aero plane and also because it could by pass any type of obstruction.
Besides saving time, it has got relative amount of safety due to the
fixed routes, heights and timings of the aero plane but whenever the accidents
occurs the chances of survival are minimum. Its major drawback is that it can only
be used by elide class of the people.
4. Seaways: - Seaways are broadly classified into two types as:
(a) Inland waterways
(b) Docks, harbours and ports
(a) Inland waterways: - Inland waterways were mainly used in accidents times
for the movement of people when other modes of transportation were not
yet developed. They were used whenever seas, rivers or any other form of
water channel was available. Nowadays it is rarely used because of the long
time it takes in order to reach from one place to another. Mostly people
use it for recreation purpose.
(b) Docks, harbours and ports: - On the other hand docks, harbours and ports
are extensively used for the transportation of heavy machinery and huge
quantity of goods and cargo from one country to another having
developed. Ports and harbours can not only fulfils their requirements but
also can earn huge amount revenue by transportation the goods of other
neighboring land locked countries. The biggest advantage of docks and
harbours is that the material at a cheaper cost besides taking proper
measures the safety of this mode can be ensured.
Minor modes of transportation: - Apart from these four systems of
transportation some other minor modes used are
(a) Pipeline
(b) Cables, ropes and elevators
(a) Pipeline: - Pipelines are used for the transportation of liquids and gases
from the source of generation to the houses and other commercial places.
(b) Cables, ropes and elevators: - This mode of transportation is used for
mainly for small groups or parts of buildings just like in a mountainous
region when you have to reach from one place to another and no road is
available. Cables are used to carry people while in multipurpose buildings
elevators are used in order to carry people from one story to another story
of the building.
Need and scope of comprehensive plan: - Following points should be kept in
mind in order to prepare a comprehensive plan for the transportation plan:
1. Straight route
2. Early grades and curves
3. Availability of land
4. Availability of material
5. Geometric design
1. Straight route: - The road, highway and railway should be aligning as
straight as possible because the construction cost is greatly decreased if the
road is constructed as straight as possible. Straight route also makes the
journey of the passengers easy and comfortable which is one of the major
prerequisite of any transportation system. Also from safety point of view
straight route is considered to be the best as chances of accidents are
minimum if you follow the rules of traffic. Another important aspect of the
keeping the route straight is to ensure less wear and tear on vehicles,
hence increasing the life of the vehicles.
2. Easy grades and curves: - Another important point of planning of transport
system is provision of easy gradients and proper curves by providing them
comfort and safety of the journey and also the vehicle life can be
maximized just like it is essential to avoid curves as much as possible and it
becomes absolutely necessary then transition curves should be provided
because the change in duration is gradual in it. In the same way proper
filling and cutting is done in order to have easy gradients along the routes
besides blasting is also done in mountainous region to prepare proper
gradients.
3. Availability of land: - Another important point to prepare a comprehensive
plan is to make sure that adequate land is available for the construction of
our proposed transportation system. Availability of land mainly indicates
that after acquiring the land, the proposed alignment should be free from
any type of dispute. It also indicates that enough space is also spread for
the future development. This rarely is one important aspect of planning
because the needs in the future will surely increase and the transportation
system will ultimately fail if the adequate land is not acquired.
4. Availability of material: - The cost of project greatly depends on the easy
and cheap access to the materials therefore in the planning stage it is kept
in mind the near by resources of material and the proposed alignment can
be changed in order to have an easy access towards material as the
construction of any transportation system highways, railways etc involve a
lot of money therefore this factor is also consider very important.
5. Geometric design: - In the planning phase it is also very important to have
proper design of the road so the life of road could be maximized certain
features which come under design are various site distances, thickness of
road and all its layers, design of embankments, design of bridges, flyovers
under passes, drainage consideration, camber, super elevations etc. All
these factors are important too much to be properly design in order to
have a safe movement of vehicles and also for the durability of the road.
Sites for bridges and tunnels: - In the construction of tunnels and bridges it is
always kept in mind that the access to the machinery and material is easy and
safe and it is also kept in mind such a site should be selected where cost is
minimum for this purpose the whole region along the proposed route is surveyed
and determine that which particular route has minimum distances for the
construction of tunnels and bridges it would greatly affect the cost of bridges and
tunnels. Similarly care should be taken in order to finalize the site for bridge so
that access to materials and machinery is safe and easy.
Free from frost and rain: - It is important to select or finalize the route according
to various weather conditions like as much as possible areas of resistant, snowfall
and rain fall should be avoided in order to increase the road life as well as safety
of the journey, therefore while finalizing the alignment such areas should by pass
and the route finalized should be made free from frost and rain.
Principles of planning: - Following points should be kept in mind while planning a
new transportation system:
A transportation system should provide a safe, efficient, comfortable,
speedy movement of people and goods.
There should be adequate amount of funds available for construction of the
transportation system because if the funds are not available then not only
the quantity of work compromised but also huge financial losses will be
suffered.
Future expansion should be kept in mind while planning a new
transportation system, therefore adequate amount of length should be
reserved and continuous monitoring should be done so that any illegal
settlement and encroachment take place. Foe that purpose trained people
or population growth and increased in the movement of vehicles moving
per year should be determined.
Available resources should be utilized up to a maximum benefit so as to
save the economy of the project.
A basic principle of planning a new transportation system is to give
maximum utility to the people.
A transportation system should be planned in such a way that it contributes
the development of the area.
Maintenance is also an important factor because transportation system
gets deteriorated if proper maintenance is not done with passage of time.
Therefore availability of funds and labors should be kept in mind for the
maintenance purpose.
Although principle of planning is to ensure the safety of passengers and
vehicles for that purpose detail traffic study should be carried out and the
network should be designed properly.
Phases of planning:
1. Economy: - The first phase of planning is the economy of project and when
we talk about the economy the first thing that comes in mind is how much
the purposed transportation system will benefit the people of that area.
For this purpose a detail survey is carried out to see how many towns,
villages and localities and cities are along the purposed alignment beside
that past train of bucklation growth are studied and future trains are
estimated. According to that transportation system is planned. Another
important thing in the economy is the development of industrial and
agricultural sectors of the area because with the construction of a new
road, railway, port or harbour will definitely facilitate the development of
the area and the country. Existing facilities are studied to see whether it is
important to enhance them or kept them at their level.
2. Finance: - After the economy is studied the second phase of planning is
finance, which actually indicates how much funds are available for the
construction of the transportation system. The funds could be in the shape
of funds generated by NGO or by international NGO donor agency, funds
donated by wealthy people with and outside the country. Estimating all
those funds and rough cost of project, affezibiliy report is prepared beside
that after the completion of the project how much revenue could be
generated from vehicle registration, different types of taxes, construction
along the highway etc are also estimated in the finance phase another
important thing is the allocation of funds for the maintenance purpose.
3. Survey: - Once a purposed project is considered feasible then the next
phase is survey. There are very stages of surveying starting with map study,
which could easily be carried out in the office and root could be purposed
after which reconnaissance is done and thing which are not mentioned in
the map are noted and slight adjacements could be made in the purposed
root after wards preliminary survey is carried out with the help of minor
instruments it gives you some more detail of the area after detail survey is
done in order to fix the alignment of the road.
4. Design: - Once a report I finalized various components of the transportation
system are design and construction becomes easy. Generally the things
which are design can be thickness of various layers of a road or highway,
the estimated vehicle load, design of pre stress bridges and tunnels,
different site distances, curves and super elevations, camber, embankment,
shoulders etc.
Railway track: -
The railway track is a structure consisting of parallel lines of rails with their
sleepers, fittings and fastenings, ballast etc to provide a road for the movement of
locomotive or coaches.
Or
Railway track is also known as permanent way. The name of permanent way is
given to the track to distinguish the final track constructed for the movements of
trains from the temporary track laid for transporting the construction materials
such as sleepers, rails, ballast etc.
The track is the rail road on which two trains run. Basically a track consists
of two parallel rails having a specified distance between them known as
gauge and fastened to the sleepers. These sleepers are embedded in a layer
of ballast of specified thickness spread over the formation. The rails are
joined to each other by fish plates and bolts and the rails are fastened to
the sleepers with the help of various fittings such as spikes and keys. The
sleepers are spaced at a specified distance and are held in position by
embedding in ballast.
Methods of Construction of railway track: -
1. Old method 2. Modern method
1. Old method: - In this method the construction work was done with the help
of labor. Mostly the machinery was not used for the transportation of
passengers and goods.
2. Modern method: - In this method the work of construction is done with the
help of machines and modern techniques and equipments are used for
construction.
Steps for construction of railway track (old method)
1. Planning: - In this initial stage we discuss the following points:-
Route of track
Advantages of track
Disadvantages of track
Contractor details
Budget
2. Survey: - In the survey we collect the data about the following points: -
Soil
Routes advantages and disadvantages
Best position of station and yards
Best track type
Best route
3. Designing: - in designing a designer finalize the following points: -
Route of track
Length of track
No of tracks
Position of stations
Type of gauge
Width of formation
Depth of ballast
Type of material which is used in construction
Every detail about the field work will be given in designing
Requirements of an ideal track: A good track should provide comfortable and
safe journey at the maximum permissible speed with minimum maintenance cost.
To achieve these objectives the track should meet the following requirements.
o The gauge of the track should be correct and uniform.
o The alignment of the track should be correct having no kinks or
irregularities.
o In straight portion of the track whenever a curve is required transition
curve should be provided which should be as straight as possible.
o Super elevation should be provided on the curve portion of the track to
sustain the effects of the centrifugal force.
o The gradients should be uniform and as gentle as possible. The change of
gradients should be followed by a vertical curve to give smooth ride.
o In order to absorb shocks and vibrations of the moving train the track
should resilient and elastic.
o The drainage system of the track should be perfect so that stability of the
track is not affected by water logging or drainage water.
o The track should be design in such a way that the load of the train should
be distributed uniformly.
o The friction between the wheels of the locomotives and the rails should be
minimum so as to avoid extra heat which could generate fire.
o Adequate provision of repair and replacement and renewal of damaged
portion should be provided.
o The track should possess high resistance to damage at the time of
derailment.
o The track should be stiff and tough in order to sustain variation in
temperature, centrifugal force and lateral trust.
o Joints, points and crossings should be designed and maintain properly.
o The track should possess antitheft and sabotage qualities.
o The track structure should be such that initial and maintenance cost is
minimum.
Components of railway track: - The track or permanent way is consisted of the
following components:
(a) Formation
(b) Sleepers
(c) Rails
(d) Ballast
(e) Fittings and fastenings
(a) Formation: - Formation is the base or foundation of the railway track. It
gives a surface where ballast rests. It takes the total load of track and the
trains moving over it. It is prepared over various layers and is of highly
importance for a proper railway track.
OR
The formation is the surface on which the track (including ballast) is laid.
Traditionally, it was the finished surface of the earthworks. It includes sub grades
and earth work and sub ballast.
Purpose of track formation: -
To make regular bed to put the ballast section.
To support the load coming for ballast and train.
To provide good drainage
Steps for construction of track foundation: -
Preparing of natural ground surface by releasing of trees.
Adding a layer of soil of 15-20cm.
Compaction of layers according to the type of soil.
The soil of good properties to be put at the top and slopes while the soil of
low properties to be put at the middle.
It must be compact well for the surface soil and gently finished without any
excavation to prevent bad drainage.
Disadvantages of track foundation: -
Unstable foundation leads to increasing of maintenance cost
Low speed of train
May cause accidents
May find soft spots filled with water which are at last caused sliding or
failure
These spots increase by increasing the movement
Sliding will happen as a result of rain. It is dangerous type of unstable soil.
Treatment of track foundation: -
Drainage of water must be away from the track
Bitumen coating should prevent the soil from water table
Releasing of trees by burning, mechanically or manually and chemically
Chemical materials to be mixed with soil to improve its properties
(b) Sleepers: - The sleepers hold the rail together in proper position and help in
providing and maintaining a proper gauge with the help of fittings and
fastenings. Besides it also transfer the load of the locomotives to the ballast
below.
Or
Railway sleeper is a rectangular support for the rails in railway tracks. Generally
laid perpendicular to the rails, ties transfer loads to the track ballast and sub
grades, hold the rails upright, keep them spaced to the correct gauge.
Purposes of sleeper: -
Keeping of rails at constant distance.
Insure elastic layer between the rail and the ballast section.
Distribute and transfer the load on layer area of the ballast section.
To resist the extension of rail due to change of temperature
Placing of sleepers: -
After the ballast section the sleepers are placed at suitable locations. 1st
alignment is also made before fixing of rails. Sleepers placed should be :