CHAPTER IV

ENGINEERING SURVEY RECONNAISSANCE -  PRELIMINARY AND FINAL LOCATION SURVEYS

 

401

Reconnaissance Survey Terms of Reference

402

field Work

404 Report
405 Estimate
406

Maps

407 Covering Note
408

Preliminary Surveys Terms of Reference

409

field Work

412 Report
413 Estimate
417

Maps and Plans

419

Covering Note

420

Final Location Survey Terms of Reference

421

Field Works

426

Notes to be made in the Field

427

The Centre Line

429

Curves

432

Transition Curves .

434

Gradient

437

Compensation for curves on Gradients

438

Bench Marks

440

Datum for Levels

441

Compass Bearings

443

Plans, Sections and Designs for Works

449

Index Plan and Section

450

The Index Plan

451

The Index Section

452

Detailed Plan and Section

453

The Plan

458

The section

467

Plans and Cross Sections of Rivers

468

Plans of Station Yards

471

Plans of Junction Arrangements

473

Detailed Drawings of Structures etc. .

Reconnaissance Survey

401. Terms of Reference. - The Project Investigator should be supplied by the Railway Administration with "Terms of Reference" as indicated in para 209.

402. Field Work.-In carrying out a Reconnaissance Survey particular attention should be paid to ascertaining the waterway required, and the best sites for stations, crossings of streams, bridges and roads. The nature of foundation which would be required for large bridges should be investigated and recorded. Materials and labour available in the area covered by the Survey should be taken note of.

403. Ruling gradient and degree of curvature for the proposed line as indicated in the "Terms of Reference" are to be considered as broad guide-line and the survey team should examine the question in detail taking into account the topography of the area, the level of traffic, the speeds envisaged, the mode of traction and above all the initial cost of construction and the unit cost of service with different alternative, and make their own recommendations. Prior approval of the Administration should be obtained before proceeding further with the survey in case a change in the terms of reference is considered desirable.

404. Report.-The report submitted after the conclusion of the survey should, as prescribed for a Feasibility Study (cf. Paragraph 501 et seq.) It should contain a definite recommendation as to whether from the financial point of view the prospects of the line surveyed are such as to make it worthwhile to undertake further investigation with a view to the construction of the project. It should be accompanied by an estimate for the construction of the line.

405. Estimate.-The form of the estimate and the amount of detail to be contained in it will depend on the character and amount of the data collected, but an approximate abstract estimate of the cost of the line surveyed in Form E. 554 accompanied by an abstract estimate of the cost of Junction Arrangements and a detailed estmate of the cost of one kilometre of permanent-way (Form E. 553) are essential and should be submitted with the report. The methods by which the figures in the Abstract Estimate have been deducted should be clearly explained in the report.

406. Maps.-The reports and estimate should be accompanied by a map of the area on a scale of 25 Km. to 1 cm. an index map on a scale of 2.5 Km. to 1 cm. and by an index plan and section on a scale of 0.5 Km. to 1 cm. horizontal and 10 m. to 1 cm. vertical the proposed route or routes being marked on them in red, and all towns and places referred to in the report clearly shown therein.

407. Covering Note.-The report, plans and estimates should be submitted to the Railway Board under a covering note as prescribed in para 545.

Preliminary Survey

408. Terms of Reference.-The Project Investigator should be supplied by the Railway Administration with the "Terms of Reference" as indicated in para 209.

409. (i) Field Work.-The field work of a preliminary survey should include a compass traverse along one or more routes with such longitudinal and transverse levels as are sufficient to prepare a "Predicted Section" of the route or routes proposed.

(ii) Where suitable aerial photographs are available, for carrying out preliminary survey by photogrammetric techniques, the "predicted section" of the route or routes proposed will be determined by plotting of contoured strip maps on 1 : 10,000 scales from aerial photographs.

Geological mapping may be done and soil surveying by photo-interpretation of remotely sensed data.

(iii) The field work should also cover a soil survey by sampling at suitable intervals, in order to obtain a fair idea of the soil classification and characteristics on the proposed route/routes. Testing of disturbed soil samples is usually adequate but Geophysical survey may be done in rocky terrain.

410. (i) The alignment need not be fully staked out with a theodolite, but stone pillars or other permanent marks should be left on the ground and indicated on the plans so that the location can be readily picked up by subsequent survey parties. Bench marks should similarly be left at intervals of about 500 mts.

(ii) Where suitable aerial photographs are available, for carrying out preliminary survey by photogrammetric technique, it will suffice if centre line pillars are provided at approaches of important bridges and portals of tunnels, important road crossings and stations sites. Bench marks should be provided near all important bridges, tunnels sites and road crossings. All these together with identifiable points should be indicated on the plan so that their location can be picked by subsequent survey parties.

411. In other respects the field work in a Preliminary Survey should approach the standards laid down for a Final Location Survey (cf. paragraph 421 et. seq.). It will depend largely on the nature of the country, and must always be sufficient to obtain a close estimate of the cost of the project.

412. Report.-The report submitted on the conclusion of the Survey should give details as in that prescribed for a Techno Economic Survey (cf. paragraph 501 et seq.).

413. Estimate.-The report should be accompanied by an estimate of the cost of the project surveyed. The rules laid down for the preparation of estimates on a Final Location Survey should be followed as closely as possible.

414. The method adopted for arriving at the figures of cost must be clearly explained in the report.

415. An estimate prepared on a Preliminary survey should under ordinary circumstances be sufficiently accurate to enable the competent authority to decide whether sanction should be accorded to the construction of the line.

416. The Railway Board may in certain instances call for estimates on a Preliminary Survey to be submitted as prescribed for a Final Location Survey. When such estimates have not been called for, the estimates to be submitted on a Preliminary Survey will be those detailed below :

  • (i) An abstract of the cost of the line surveyed in From E. 554 accompanied by an abstract estimate of junction arrangements.

  • (ii) Detailed estimates on the prescribed form for the following:

Head of Account    Particulars Form
(a) Capital 1120 Land E. 553
(b) Capital 1132  Tunnels E. 553
(c) Capital  1151-53 Major Bridges E. 553
(d) Capital 1154-56 Minor Bridges E. 553
(e) Capital 1140 Detailed estimate of one km. of permanent way E. 553
(f) Capital  2000 Rolling-stock E. 553
(g) Capital  1180-90  General Charge E. 553
    

Note. Classification indicated are those corresponding to New lines and shown as example.

417. Maps & Plans. The report and estimates should be accompanied by the same maps as for a reconnaissance surveys and by plan and section on a scale of 0.1 Km. to 1 cm. horizontal and 10 metres to 1 cm. vertical.

418. (i) The detailed plans and sections and other drawings, as prescribed for a Final Location Survey should be made out with as much detail as the information obtained in the field will allow out need not be submitted with the report and estimates unless called for by the Railway Board.

(ii) Where, suitable-aerial photographs are available for carrying out preliminary Survey or photogrammetric techniques, the scale of detailed plans and sections may be 100 m. to 1 cm. Horizontal and 10 m. to 1 cm. vertical instead of 50 m. to 1 cm. horizontal and 5 m. to 1 Centimetre vertical as prescribed in Para 452.

419. Covering Note.-The report, plans and estimates should be submitted to the Railway Board under a Covering Note as prescribed in para 545.

Final Location Survey

420. Terms of Reference.-The Project Investigator should be supplied by the Railway Administration with "Terms of Reference" as indicated in para 209.

421. Field Work.--A Final Location Survey should be based on a good theodolite or traverse, which should approximate as closely as possible to the centre line to be finally adopted.

422. Unless otherwise specified the survey operations should be sufficiently comprehensive to secure the information necessary for the preparation of the detailed plans and sections required under paragraph 443 et seq. and, having regard to all the circumstances of the case (including the probable working expenses), to ensure that the alignment selected is the most economical obtainable.

423. The amount of detail in sectioning will, to a great extent depend on the nature of the country traversed. Gross sections should be taken wherever the Engineer considers them necessary. The information collected during the course of the survey should be such as will enable the preparation of a fairly accurate estimate of the cost of the line.

424. Investigations should be made of bunds, bunded streams and irrigation works in the vicinity of the projected line which might affect the future safety of the line. In arriving at decision on the waterwaysthe engineer should pay due regard to these works and consider the alternative of altering or diverting the bunds, irrigation streams etc., even it would mean incurring some expenditure on such alternations, if that would save a larger expenditure on the waterways.

425. In the case of passage through hills, the geological characteristics of the country should be investigated by the Engineer, particularly in respect of the probable stability of the line, and if the importance of the work requires it, the Railway Administration should apply for the assistance of an officer of the Geological Survey of India.

As the method of construction of earthwork will be dependent largely on the nature and classifications of the soils a systematic soil sampling at suitable intervals and upto sufficient depths depending upon the nature of terrain should also be done all along the proposed route. Wherever borrow areas are not located along the alignment soil samples should be collected from such places also. These samples shall then be tested for the standard properties, bore logs prepared and the data used for designing the profiles of the embankments and cutting foundations of important structures as well as the method of undertaking the earthwork.

426. Notes to be Made in the Field.-During the Survey, careful notes with dates should be made on the ground, from personal enquiry and observation regarding any information likely to be useful in working out the details of the project.

427. The Centre Line.--The unit of measurement for the centre line should be the chain of 20 metres. The centre line finally located should be marked out by pegs at every 20 metres. At each 100 metres a large peg should be used; these 100 metres pegs should have their numbers branded or stamped on them in figures not less than 25 mm high. The numbers branded on the pegs should indicate hundreds of metres; thus 57 would mean a distance of 5700 from the zero chainage.

428. Masonry pillars should be built at the tangent points of curves and along the centre line at intervals of not less than 500 metres.

Curves will generally be described by their radius of curvature in metres but may also be expressed in degrees as defined above for convenience in setting.

429. Curve.--Curves should be defined both by their "degrees of curvature" in degrees and minutes and by their radius in metres. The degrees of curvature should be taken as the angle at the centre subtended by an arc of 30.5 metres in length. The radius of a 10 curve is 1747.52, say 1750 metres; the radius of other curves may be obtained by dividing 1750 metres by the degree of curvature.

430. The apex angle formed by the intersections of the tangent should, if practicable, be observed if not, it should be calculated.

431. Large pegs, distinguished in some suitable manner from the 100 metre pegs, should be put in on the straight at the calculated tangent length from the apex and also at the offset distance (see paragraphs 432 and 433) measured at right angles to the tangent at this point, from which., as a rule, the circular part of the curve is laid out.

432. Transition Curves.-Changes of curvature (whether at the junction of a straight line with a curve or in the middle of a compound curve) should be effected by means of "transition curves". This entails the "offsetting" or "shifting" inwards of circular curves pegged out primarily with a theodolite from the tangent point mentioned in paragraph 431. See also paragraph 218.

433. The amount of "shift" depends on the length of transition curve, which length usually depends on the amount of cant and the distance in which it is run out. See also paragraph 218.

434. Gradients.--Gradients should be defined by the distance in which a rise or fall of one metre occurs per 100 metres length. Thus a rising gradient of 0.5 metre in hundred metres is to be described "Rise 1 in 200 (0.5 per cent)."

435. All lines should be graded with due regard to the possibility of additional intermediate stations being constructed later on.

436. Sharp changes of gradient should be avoided, if possible on curves. All sharp changes of gradient should be eased off by vertical curves.

437. Compensation for Curves on Gradients.--All gradients should be compensated for curvature if the ruling gradient would otherwise be exceeded. The compensation to be allowed should ordinarily be 0.04 per cent degree of curvature on the 1676 mm gauge, 0.03 per cent degree on the metre gauge, 0.02 per cent on the 762 mm gauge, and 0.015 per cent on the 610 mm gauge. Compensation should be allowed on easy curves as well as on sharp ones.

438. Bench Marks.-Bench marks should be left at intervals of not more than one kilometre along the line and at sites of important bridges. In every case the position chosen for a bench mark should be such that it can be conveniently referred to during construction and is, at the same time, not liable to be interfered with during the progress of construction.

439. Bench Marks should be of such character or construction as not to be readily moved or injured by accident or mischief. All bench marks should be so placed and marked as to be easily identified and their correct description and location should be recorded.

440. Datum for Levels.-The datum to which all levels should be referred is the Mean Sea Level as adopted for the Great Trigonometrical Survey of India. During the progress of the survey and location of the line every opportunity should be taken to connect the levels with any survey of India level stations in the neighbourhood, and to check the difference between any temporary datum and Mean Sea Level.

441. Compass Bearings-The compass bearing of each tangent should be taken at every curve in level country, and the mean of the readings at the two ends should be recorded as the average bearing for each straight line.

442. In hilly country where curves are frequent it will sufficient to take such bearing at about 2 or 3 places in each kilometre.

443. Plans, Sections and Designs for Works-A set of plans and sections for a project should consist of :-

  • (i) General Map of the country traversed by the project scale about 25 Km. to 1 cm.

  • (ii) Index Map, scale about 2.5 km. to 1 cm.

  • (iii) Index Plan and Sections.

  • (iv) Detailed Plans and Sections.

  • (v) Plans and Cross Section.

  • (vi) Plans of Station Yards.

  • (vii) Detailed Drawings of Structures.

  • (viii) Plans of Junction Arrangements.

444. As exception to this rule, Index Plans and Sections and plans of stations may be longer than 1200 mm if necessary, to enable all the information to be shown on one sheet. In such cases, however the width of 840 mm should still be kept to, and the length in excess which, however, should not exceed 1020 mm should be folded so as not to project beyond the edges of the other sheets.

A Catalogue of maps published by the Survey of India is obtainable from the Director, Map Publication Survey of India, Hathibarkala Estate, Post Box No. 28, Dehradun-24800.

2. The latest information on availability of maps and aerial photographs of the region would be available from the concerned Regional Director of Survey of India.

445. Throughout each set of plans and sections the kilometrage should be reckoned from the same fixed point. This fixed point should, if practicable, be at that end which is in the direction of the nearest sea port with which the line is in through communication by rail, and should be clearly defined on the Index Plan and section and on at least the first and last sheets of the Detailed Plans and sections. If the line takes off from an existing railway station the zero point should be fixed at the centre of the existing station yard, and when it ends at an existing station the end of the survey should be taken as the centre of that station. Each sheet should be plotted in the direction of the through kilometrage so the kilometrage may be read from left to right.

446. The datum used for all plans and sections should be Mean Sea Level, and all heights should be referred to this datum in metres and decimals. If any other datum is adopted for temporary use during the progress of the survey the figures referring to such temporary datum should be reduced to Mean Sea Level before being entered on the plans and sections.

447. On each sheet should be noted a reference number of letter, the name of the Railway or section of railway, the gauge and the scale. The scale may be described in works, and need not be drawn. The magnetic north should be indicated on each map and plan by a line not less than 150 mm. in length.

448. The Index Plan and Section and the first and last sheets of the set of Detailed Plans and Sections should be signed and dated by the Engineer in charge of the survey. Every sheet should be signed and dated by the officer responsible for its preparation.

449. Index Plan and Section-The Index Plan and Section should be drawn to a scale of 0.5 km. to a cm. horizontal and 10 metres to a cm. vertical, the plan being drawn above the section on the same sheet.

450. The Index Plan--On the Index plan should be shown all towns, roads, canals, rivers, hills boundaries of States and districts within a distance of 10 kilometres on each side of the railway. The centre line of the proposed railway should be indicated by a full red line 0.8 mm in thickness. The degree and radius of all curves should be figured. The position of each station should be shown by a red block, the name of the station being given. The kilometrage from the "fixed point" should be marked and figured at every kilometre and the extent of each sheet of the detailed plan shown. Where practicable the Index Plan should be traced from the sheets of the Survey of India map published to a scale of 0.5 km to a cm. the details in the immediate neighbourhood of the railway being filled in or corrected, if necessary, from the information given by the railway survey. For districts where a map to the scale of 0.5 km. to a cm. is not available, the information required should be plotted to that scale from such other maps or data as can be obtained.

451. The Index Section.-The Index Section should show the formation level by a red line; the gradients should be figured, and the height of formation above Mean Sea Level entered at each change of gradient. The position of each important bridge with the name of river and number and size of bridge spans should be indicated, also level crossings with their classification "as special", "A", "B", "C" or "D" class and position of each station with its name and distance from the "fixed point". The kilometrage from the "fixed point" should be marked and figured at every kilometre.

452. Detailed Plans and Sections.-The detailed plans and sections should be drawn to a scale of 50 metres to a cm. horizontal, and 5 metres to a cm. vertical, the plan in each case to be above the section on the same sheet. 5 kilometres of line should be illustrated on each sheet, and the divisions between the sheet in each case should be a kilometre-mark. To admit of the sheets being readily connected, each sheet should have a skeleton outline for a few decametres beyond the kilometre-mark at each end repeated from the adjoining sheets on both the plan section. In difficult or mountainous country, if the Engineer considers it necessary, the plan should be made on a large scale, such as 25 or 10 metres to a cm.

Note. Where the State Governments have prescribed separate scales for plans and sections in respect of acquisition of land for railway projects, such scales should be adopted.

453. The Plan.-On the plan should be shown in detail all features of the country within a distance of 100 metres on each side of the centre line of railway and the boundaries of village lands. The boundaries of different kinds of cultivation, forest, pasture, waste, etc. should also be marked on the plan. The centre line of the proposed line should be indicated by a full red line 0.8 mm in thickness. The position of all masonry centreline pillars and the exact position and description of each bench-mark should be shown.

454. In addition to the foregoing, the following details should be shown, in so far as they lie within a distance of 300 metres on either side of the centre line :

  • (i) Rivers requiring a waterway of 12 metres or upwards.

  • (ii) Important road with their bridges, culverts, and fractional kilometres-marks.

  • (iii) Canals and large tanks, bunds, bunded-streams and irrigation works.

  • (iv) The outlines of all towns and villages and in the case of large towns, the important streets and thorough fares.

  • (v) The boundaries of States, Local Administration, Divisions and District.

  • (vi) Hill peaks and other important features of the country.

  • (vii) Survey of India Stations.

  • (viii) Camping grounds, rifle ranges, etc.

  • (ix) Reserved Forests.

  • (x) Industrial units existing and/or under construction.

455. Care should be taken to give sufficient topographical details to exhibit the contour of the ground and to justify the alignment selected.

456. All new works proposed for the purposes of a new railway line or for the accommodation of the public should be marked on the plan, also all alterations, diversions, protection works & c., proposed in connection with existing railways, roads, rivers, canals or tanks. The "pattern for detailed plan" given at the end of this book should be taken as a model for this purpose.

457. In the case of a junction with an existing railway, the plan should show the existing line for not less than one kilometre on each side of the proposed junction, the proposed junction arrangements and the position on all buildings, bridges, level crossings, kilometre posts and other works on, or marked and the angle of curvature noted.

458. The Section.--On the section, the formation level should be shown by a red line, the ground line being black. If practicable, throughout each sheet, the ground line and formation should be continuous, i. e., without "steps" or changes of datum; for long length of steep ruling gradients it is advisable to incline and "step" the datum line.

459. Two sets of heights or level should be given (1) Height of ground above Mean Sea Level, and (2) Height of formation above Mean Sea Level. The first set of figures showing ground level should be the lowest in position, i. e., nearest the bottom of the sheet. The heights of or levels should be given in metres to two places of decimals and entered at every 20 metres, vertical ordinates being ruled up to connect the figures with the ground line. These vertical lines should be in blue, except where they occur at a change of gradient where they should be red. A model "pattern for detailed section" is given at the end of this book.

460. The bed level and high flood level of all rivers and streams should be shown; also the position, description and (level to two places of decimals) of all bench-marks and position of all masonry pillars.

461. Gradients should be entered in a plain and conspicuous manner. At each change of gradient an ordinate should be drawn in red up to formation level, and the height of formation noted to two places of decimals. Where a change of gradient occurs at any point other than at the 20 metres marks, the chainage of changing point should be noted.

462. In addition to the above important details, such as the tangent points of all curves, the kilometrage and chainage, the general description of the soil, the position of all bridges, level crossings & c., and the points where roads or waterways are diverted; should be shown.

*For a set of tracings submitted to the Railway Board, it will suffice it heights or levels are entered at every 200 metres instead of at every 20 metres.

463. Tunnels should be drawn to scale on the section, and the length in metres should be noted in each case.

464. A station should be indicated by a vertical red line at each and drawn upwards from formation level to define the limits of the station yard. The name of the station and the length in metres of the station yard should be noted.

465. Where cross sections have been taken, a reference to each should be given on the main section with a vertical line indicating the position. Cross sections may be plotted to a natural scale, both the vertical and horizontal scales being the same as the vertical scale used for the main section 5 metres to a cm. On each cross section the outline of the cutting or embankment should be correctly shown. For many practical purposes it will, however, be possible to give all the information required from cross sections by contour lines on the detailed plans.

466. Cuttings should be graded with special reference to efficient drainge.

467. Plans and Cross Sections of Rivers.-For all rivers requiring a provision of waterway of 110 sq. metres or upwards plans and cross sections showing the following particulars should be furnished, subject to the provisio that the Engineer may exercise his discretion as to the necessity for these plans and sections in mountainous country :-

(a) Plan.-The plan should be drawn to a scale of 50 metres to a cm. of such portion of the river and its affluents as may lie within a distance of about 2 km. from the proposed centre line of the railway, measured from any point on that centre line, or such further distance as the Engineer may consider necessary. The direction of the current should be indicated by arrows.

(b) Cross Section.-Three cross sections of the river bed are required, plotted to a natural scale of 5 metres to a cm. Where the width of the river in flood exceeds 1000 metres this scale may be reduced. With a width from 500 to 1000 metres the cross section should be plotted in two halves. The cross sections should be taken at typical points selected at intervals of about 2 kilometres measured along the centre of the river bed. On each cross section lines are to be drawn to indicate the level of highest known flood, ordinary flood, and ordinary low water, with the reduced level figured on each. On the cross section taken on the centre line of railway an elevation of the proposed bridge should be drawn to scale in its proper position. The chainage should be figured on the cross section. Where borings or trial pits have been sunk, their position, with a note on results, should also be given. The cross sections may be plotted on the same sheet as the plan, or on separate sheets as may be found convenient in each case.

468. Plans of Station Yards. -For stations requiring a special design, a plan of the station yard to a scale of 10 metres to a cm. is required, showing all lines, sidings, platforms, buildings, wells, tanks, water-cranes, ash-pits, turn-tables, traversers, weighbridges, signals, etc. within the boundary of the station yard; also any roads, buildings, etc., lying outside the station yard but immediately adjacent there to-The name of each work or structure should be entered against it on the plan, with such notes and dimensions as may be necessary to define its size, position and purpose for which intended.

469. For other stations, made according to type designs, a plan giving similar information is required for each different type or arrangement adopted. On each type plan should be noted the names of the stations which are to be laid out in general accordance with that plan, with a description of any important variations adopted at one or more of those stations.

470. In designing the station yards the Open Line Administration should be consulted and full provisions should be made for extensions for future developments of traffic, but nothing should be estimated for which is not absolutely essential for dealing with the traffic expected in the first five years of working, everything in excess of this being shown in dotted lines and left to be added when actually required.

471. Plans of Junction Arrangements.--Plans of Junction stations of 10 metres to a cm. similar to the plans prescribed in paragraph 468 for Station Yards are required, showing clearly in full red lines the proposed works necessary to deal with the traffic expected during the first five years of working, and in dotted red lines the provisions made for future development of traffic.

472. Except where the new line is of a different gauge and has entirely its own arrangements, the plans for the junction arrangements should as a rule be prepared by the open line administration in consultation with the Engineer.

473. Detailed Drawings of Structures, etc.-Though many of them are not required for submission to the Railway Board with a construction estimate, drawings of all schemes should be prepared in order that sufficiently accurate estimates can be compiled. These drawings should be carefully recorded for future use.

474. The drawings which are usually required by the Railway Board are as follows :

  • Type drawings of banks, cuttings and tunnels in cases only where the proposals differ from the prescribed maximum and minimum dimensions.

  • Skeleton outlined drawings to small scale of all large bridges.

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