Surveys
By Shri Benhur, SSO(A)/Hqrs/SC Rly
ü A thorough examination of geographical area, to gather information or measure and record the details of an area of the land.
ü Preliminary investigations are conducted to collect data prior to the actual commencement of construction of New Line, GC, Doubling other traffic facility works.
ü Hither to, the field work in survey was a complicated issue but with the usage modern technology the surveys have become easier with accurate results as compared to the good old days.
ü Some of the modern equipments used in conducting surveys are :
1.Large scale topographic Maps.. Contains large scale details, shows natural and manmade features
2. Precision Maps … It produces scrollable, zoom able maps inside UI view without an internet
3. Air Cameras.. Drones
4. Electronic distance measure.. Electromagnetic energy determines the length of the line
5. First order plotting.. Program based Graphs.
Types of Surveys in Railways
1. Reconnaissance Engineering cum- Traffic Survey (RECTS) (Budget Rs. 10000/- per KM)
ü A detailed survey of traffic conditions of a section of an area with a view to asses the traffic prospects and financial implications of new line, other traffic facilities, GC, Doubling & other Line capacity works.
ü A thorough investigation will be carried out by the team to assess the potential sources to generate traffic Viz:
1.General characteristics of the area and extent of cultivation
2. Local industries and religious festivals
3.The general conditions such as prosperity of people in the locality and density of population and its distribution
4. The probable amount of traffic to be served by the new railway line.
5. The probable new lines to be opened up to join large trade centers.
6. Nature and volume of exports and their destination and origin
7.The amount of imports and centers of their distribution
8. Possibilities of development of new industries and irrigation schemes as a result of new railway lines
9. Tourism and Tourist prospects
RECTS-II
An Engineering survey involving rough and rapid investigation of an area. In this survey all the possible routes have to be examined along with the construction and operational cost of a Projected line.
This survey should collect the following information:
1. Physical features of an area like Hills valleys water bodies, wetland climate islands etc.
2. Nature of soil
3. Streams and rivers in the area especially those likely to be crossed by the track, their direction of flow, approximate width and depth.
4. Position of hills and the lakes.
Besides indicating the approximate distance, height, curvature, Necessity to cut and fills suitable sites for the station major Bridges Roads etc,.
Instruments used in Reconnaissance survey
1.Aneroid Barometer: used for measuring the atmospheric pressure
2.Prismatic Compass: It’s a navigating and surveying instrument used for determining course, way points and directions.
3. Binoculars telescope
4. pedometer: It records and displays the number of steps you take based on the body movements
The data collected are tabulated to gauge the projected traffic potential of the proposed new line and survey report with all the details collected along with the details of other alternate routes examined will be submitted to the competent authority
II. Preliminary Engineering cum- Traffic survey (PECTS) (Budget Rs. 15000/- per KM)
The object of this Survey is
1.To conduct the survey work along the alternative routes (found out by reconnaissance survey) with the help of theodolite and leveling instruments.
2. To determine the greater accuracy of the cost of railway line, along with the alternative routes, involving cost of removing obstruction, construction of bridges etc.
3.To decide the most economical and efficient route
Importance of PECTS
The preliminary survey decides the final route and recommend, only one particular route in preference to other alternatives. Thus, the preliminary survey should be carried out with greater precision as the alignment of final route depends on it.
Instruments used in preliminary survey
1. Dumpy Level
2. Prismatic Compass
3. Tachometer
4. Plane Table
Final location survey (FSL)
This survey will be under taken only when it is decided by the competent authority that the project will be taken up for construction.
The works involved in a Final location survey can be briefly assumed as under:
1. Staking of the centre line.
2. Leveling along with centre line
3. A plane table survey of the strip of he land on either side.
4 A plane table survey of Rivers, Station site and junction arrangements.
Instruments used
1. Theodelite
2.Precise Level
3. Steel Tape
Before a decision is taken to make investment in a project it is necessary to examine various alternatives including optimization of operating point of view and best line is selected to make an ideal investment.
The survey report will have following chapters:
1. Introduction
2. Traffic Projections
3. Analysis of alternatives
4. Characteristics of project area
5. Standard of Construction
6. Route selection
7. Project Engineering
8. Cost, Phasing and investment schedule
9. Financial Appraisal
10.Recomendation
Basic Principles of Survey
1. To work from the whole to the part.
The whole area is first enclosed by main points ( i.e controlling stations) and main survey lines. The area is then divided into number of parts by forming well conditioned triangles.
The main survey lines are measured very accurately with a standard chain, then the sides of the Triangles are measured.
II. To locate a new station by at least two measurement (linear & angular) from fixed points
The points are located by linear or angular measurement or by both in survey.
Let A & B are control points then C is established .
The distance between A & B can be measured accurately and then plotted on the sheet to some scale.
Productivity Test.
Productivity test is a test applied to see if the works sanctioned due to having been considered as productive or remunerative have or not actually proved as such. Accordingly earnings there from or savings in working expenses eventually realized are carefully compared with those anticipated. This examination is called as Productivity Test.
This test is not applied for the following works:
1. Residential Buildings
2. Assisted Sidings & Rolling Stock.
New Lines
The actual cash inflows and the rate of return for each year to the end of 5th /7th year from the date of commissioning the project is worked out and the results of the review are prepared along with the following statement.
1. Passenger earnings from traffic local to the branch line
2. Other coaching earnings from traffic local to the branch line
3. Tonnage of goods Traffic from traffic local to the branch line
4. Tonnage of goods traffic interchanged with the existing lines
5. Earnings from Goods traffic local to the branch lines
6. Earnings from goods interchanged with the existing lines.
These statements are prepared and sent for each financial year after the date of opening of the line for a period of11 years.
Open line works
The works undertaken with a definite object of increasing earnings or reducing expenditure to which such test can be applied with in three to five years of their completion will be selected out of those charged to capital on the grounds of remuneration.
A statement in following format is prepared.
1. Reference to sanctioned estimate
2. Brief particulars of works selected for application of Productivity test
3.Total estimated cost.
4. Nature and extent of productivity claimed in the estimate.
5. Brief remarks about the results of the test
The object is not only to furnish the results actually achieved to the authority who sanctioned the estimates but also serves as a guiding factor in future.
