GEOMETRIC DESIGN OF RAILWAY TRACKS

2. RAILWAY TRACK CONSTRUCTION,
MAINTENANCE AND OPERATION

3. Earthwork – Stabilization of track on poor soil -
Tunnelling Methods, drainage and ventilation -
Calculation of Materials required for track laying -
Construction and maintenance of tracks - Modern
methods of construction & maintenance - Railway
stations and yards and passenger amenities- Urban
rail - Infrastructure for Metro, Mono and
underground railways.

4.  Generally, the width of formation depends on the number of
tracks, gauge of the tracks, centre to centre distance between the
tracks, width of the ballast layer and width of trenches to drain
off water.
 The width of formation is normally kept sloping from the centre
for drainage purposes.
 The stability of slopes depends on cohesion and friction.
 For cutting 1-5 to 1 or steeper and embankments 1:1 to 2:1

6. Subgrade: is the naturally occurring soil, which is prepared to
receive the ballast, sleepers and rails for constructing the railway
track. It is also called as formation. It may be embankment, cutting
or level depending upon the ground conditions.
Embankment: It is a raised bank of earth or other materials
constructed above the natural ground. It is constructed when
railways have to be carried in low grounds or valleys.

7. Cutting: The raised ground or hill is cut or excavated for providing the
railway line at the required level below ground level.
Level: It is prepared surface which receives ballast without raising or
lowering thee level of the ground.
Formation: The prepared surface which is ready to receive the ballast
is called formation.
Width of formation: It is the width of the prepared surface to receive
ballast.

8. Features of railroad bed level: When the formation is to be made on
embankment or cutting, various features should be carefully
considered.
1. Width of formation: The width of formation will depend on:
 The number of tracks,
 Gauge of tracks,
 Centre to centre distance between the tracks

9.  Width of ballast layer
 Width of trenches to drain off water, if necessary.
 The width of formation is normally kept sloping from the centre
for drainage purposes.
The minimum widths of formation recommended for
different gauges are shown in table:

11. 2. Slopes of sides: The stability of the earthwork depends mainly on
two factors, namely, cohesion and friction. For temporary stability,
cohesion is useful and reliable. But permanent stability is achieved
only by friction which keeps the slopes at the natural angle of repose
of the material.
The slopes to be provided to the sides of the formation should
be slightly flatter than the angle of repose of the material. The slopes
in cuttings vary from nearly vertical to 1.5 to 1 or steeper.

12. 3. Drains: The accumulation of water reduces the friction in all
sorts of soils. In case of embankments, the rain water is easily
drained off. But in case of cuttings, drains are to be provided. The
side drains are constructed along the track at a depth of about 1200
mm from the rail level. The size of drains will depend on the
quantity of water to be drained. Sometimes, pipes of stoneware or
concrete are laid in a trench with open or half open joints and
covered with porous material.

13.  The ideal material is soil containing gravel, sand, clay and silt in
equal proportions with the moisture slightly above the plastic
limit.
 Non-cohesive soils in subgrade satisfy all the requirements of
good subgrade and do not need any improvement. But heavy
clay, peat soils, loamy soils containing clay should be avoided.

14. The following are four usual methods of stabilization of
track on poor soil:
a) Admixtures of different soils
b) Sub-drainage
c) Blanket
d) Cement grouting
e) Sand-piling
f) Concrete mats or slabs

15. a.) Admixture of different soils:
 Constituents are brought from borrow pits and mixed together
during the process of spreading on the top of the bank before
compaction.
 Sandy materials are mixed with clayey materials to reduce the
plasticity of clay and provide internal friction.

16.  The best material should be reserved for filling 75 to 1m of the
bank at the top and the practice should be to use sandy and
gravelly material just below the ballast rather than clayey or silty
material.
b.) Sub drainage
 Useful for sandy or gravel soils, underlying impermeable ones.
 Trenches are excavated longitudinally beyond the toes of
formation.

17.  And also across trenches at intervals of 15 metres and connected
to longitudinal trenches.
c.) Blanket:
 A blanket of non-cohesive soil is used.
 It will improve its bearing and drainage properties
d.) Cement grouting:
 To stabilize the weak soils.

18.  Also used to strengthen the entire subgrade
 Cement and sand mixed with water to make slurry.
 The ratio of cement to sand may vary from 1:1 to 1:12 and even
more.
 There are two types of grouting one is Pneumatic injection and the
other one is Hydraulic injection.
 The injection points are places a 1.5 to 1.8m interval in staggered
position at both the ends of the sleepers.

20. e.) Sand piling:
 A series of holes of 30 cm dia are driven with a steel instrument
inside and outside of rails upto a depth of 1.8m to 3m and filled
with sharp clean and the track is resurfaced.
 These holes are driven vertically into the subgrade by means of
augers or similar tools or by driving wooden piles and taking
them out.

22. f.) Concrete mats:
 For subgrade improvement, sometimes precast concrete mass or
slabs have also been used between the ballast section and top of
the subgrade.
 This is done for encuring an even distribution of load from the
ballast to the formation or subgrade.

24.  A tunnel is a underground passage for transport of passengers,
water, sewage, minerals, gas, etc.
Methods of tunneling: Tunneling through rock:
1. Full face method
2. Heading and benching method
3. Cantilever car dump method
4. Drift system
5. Pilot tunnel method

25. Tunneling through soft ground:
1. Fore poling method
2. Needle beam method
3. Five piece method
4. Liner plates method
5. Other methods.
Methods of Tunneling through SUB-AQUEOUS STRATA:
1. Shield tunneling
2. Plenum process or compressed air tunneling

26. Full face method:
 Selected for small tunnels (diameter do not exceed 3 m).
 In this method, the full face or the entire facade of the tunnel is
tackled at the same time.
 Vertical columns are erected at the face of the tunnel and a large
number of drills mounted or fixed on these columns at a suitable
height.
 . A series of holes measuring 10 mm to 40 mm in diameter with
about 1200 mm centre-to-centre distance are then drilled into the
rock, preferably in two rows. These holes are charged with
explosives and ignited. Next the muck is removed before
repeating the process of drilling holes.

27. Heading and bench method:
 In this method, the heading (top or upper half) of the tunnel is
bored first and then the bench (bottom or lower half) follows.
The heading portion lies about 3.70 m to 4.60 m ahead of the
bench portion.
 In hard rock, the drill holes for the bench are driven at the same
time as the removal of the muck. The hard rock permits the roof
to stay in place without supports.

28. Drift method:
A drift is a small tunnel measuring 3 m × 3 m, which is
driven into the rock and whose section is widened in subsequent
processes till it equates that of the tunnel. A number of drill holes
are provided all around the drift and these are filled up with
explosives and ignited so that the size of the drift expands to
become equal to the required cross section of the tunnel.

29. The position of the drift depends upon local conditions; it
may be in the centre, top, bottom, or side .Field experience has
shown that the central drift is the best choice, as it offers better
ventilation and requires lower quantities of explosives. The side
drift, however, has the advantage that it permits the use of timber to
support the roof.

30. Pilot tunnel method: This method normally involves the digging
of two tunnels, namely, a pilot tunnel and a main tunnel. The cross
section of the pilot tunnel usually measures about 2.4 m × 2.4 m.
The pilot tunnel is driven parallel to the main tunnel and
connected to the centre line of the main tunnel with cross cuts at
many points. The main tunnel is then excavated from a number of
points.

31. The pilot tunnel offers the following advantages.
(a) It helps in removing the muck from the main tunnel quickly.
(b) It helps in providing proper ventilation and lighting in the main
tunnel.

32. Shield Tunnelling Method:
 This method involves the use of shield machine to drive the
tunnels below the ground.
 After completion of a work shaft, the shield machine is lowered
into the shaft and assembled there before excavation and
construction of the tunnels using precast concrete lining
segments of about 1.2 meter width.

33.  This construction method causes minimal disruption to traffic
and the environment because all the work takes place below
ground and the ground level environment is unaffected.

35. Cut and cover method:
This construction method, whereby the site is fully excavated, the
structure built and then covered over, uses diaphragm walls as
temporary retaining walls within the site area.
Step one :Construction of diaphragm walls, pin piles, and decking.
Step two :Excavation within the diaphragm walls, installing struts
as work progresses.

36. Step three :Construction of permanent floor slabs and walls.
Step four : Fitting out the internal structures, backfilling, and
reinstating the surface structures.

38. Forepoling method:
 Forepoling is an old method of tunnelling through soft ground. In
this method, a frame is prepared in the shape of the letter A,
placed near the face of the tunnel, and covered with suitable
planks.
 Poles are then inserted at the top of the frame up to a viable
depth.

39.  The excavation is carried out below these poles, which are
supported by vertical posts.
 The excavation is carried out on the sides and the excavated
portion is suitably supported by timber.
 The entire section of the tunnel is covered thus. The process is
repeated as the work progresses.

42. Linear plate method: In
the linear plate method
timber is replaced by
standard size pressed steel
plates. The use of pressed
steel plates is a recent
development.

43. Needle beam method:
 The needle beam method is adopted in terrains where the soil
permits the roof of the tunnel section to stand without support for
a few minutes.
 In this method, a small drift is prepared for inserting a needle
beam consisting of two rail steel (RS) joists or I sections and is
bolted together with a wooden block in the centre.

44.  The roof is supported on laggings carried on the wooden beam.
 The needle beam is placed horizontally with its front end
supported on the drift and the rear end supported on a vertical
post resting on the lining of the tunnel.
 This method of tunnelling is more economical compared to other
methods.

46. American method:
 In this method a drift is driven into the top of the tunnel.
 The drift is supported by laggings, caps, and two vertical posts.
 The sides of the drift are then widened and additional support is
provided using timber planks and struts.
 The process of widening is continued till it reaches the springing
level.

47.  Wall plates are fixed at the springing level, which in turn are
supported by vertical posts.

48. The English method:
 (crown-bar method, figure left) started from a central top
heading which allowed two timber crown bars to be hoisted into
place, the rear ends supported on a completed length of lining,
the forward ends propped within the central heading.
 Development of the heading then allowed additional bars to be
erected around the perimeter of the face with boards between
each pair to exclude the ground.

49.  The system is economical in timber, permits construction of the
arch of the tunnel in full-face excavation, and is tolerant of a
wide variety of ground conditions, but depends on relatively low
ground pressures.

50. The Austrian (cross-bar) method:
 Required a strongly constructed central bottom heading upon
which a crown heading was constructed.
 The timbering for full-face excavation was then heavily braced
against the central headings, with longitudinal poling boards built
on timber bars carried on each frame of timbering.

52. Drainage of tunnels: Proper arrangements have to be provided to
take out the water during driving operations, which interfere with
setting out, driving and lining operations of the tunnel. The
following are the ways in which one of the methods has to be
arranged for the drainage system of tunnels:
1. Sumps
2. Grouting
3. Pumps

53. Sumps:
 Connected by a pipe line at a distance of about 305m and water
is pumped from one sump to the other until it is thrown out of
tunnel opening.
 Dimensions of the sump and the capacities of the pumps varied.
Grouting:
 If water is percolating from the sides or from the top of the
tunnel and in such cases. Grouting is adopted to make the seams
water-tight.

54. Pumps:
 It is required when large quantities of waters are met, pumps
cannot cope up with the drainage.
 A method often adopted under such circumstances is to construct
a parallel pilot tunnel at a lower level than the main tunnel and
water to be drained is diverted to the pilot tunnel.

55.  Workers involved require fresh air
 To remove the dust, objectionable gases and dynamite fumes
formed during blasting and other operations
 Ventilation may be achieved by means of fans which may be
blow-in or exhaust type.
 Shafts are used for ventilation after the construction of the
tunnel. It may be working shafts or ventilation shafts.

56.  PWI inspects every tunnel once in a year after the monsoon
season.
Points to be noted during maintenance:
 Slopes of portals at the entry and exit should be checked
 Masonry cracking or deterioration
 Any signs of movement of the masonry units should be noticed
 The track through the tunnel should be in line and level

57.  All the weep holes and side drains should be periodically
checked..
 Ventilation shafts should be free from vegetation growth
 Precautions to prevent leakage
 Maintenance of tunnel should be carried out under the protection
of engineering signals.
 Position of reference marks and level pillars

58.  The sources of water for this purpose include ground water and
water collected from the washing of bore holes.
 Water seeping in up through the ground as well as from the
washing of bore holes is collected in sump wells and pumped
out.
 If the tunnel is long, a number of sump wells are provided for the
collection of water.

59.  After the construction is over, drainage ditches are provided
along the length of the portion of the tunnel that slop from the
portal towards the sump well and are used for pumping the water
out.

60. RAILS
 Standard length for B.G= 12.8m
 No of rails per km for BG lines = 1000*2/Length of rails in ‘m’
= 1000*2/12.8
= 157
 Weight of rails in tonnes per km = (No of rails X length of the
rail in m X weight of rail in kg per m)/1000
= 157X12.8X44.7/1000
= 90 metric tonnes.

61. NUMBER OF SLEEPERS
 No of sleepers to be used depends on sleeper density.
 Assume sleeper density to be M + 4, WHERE M is the length of
the rail in meters.
 No of sleepers per rail = 12.8+4 = 16.8
 No of sleepers per km = (157/2)* (16.8) = 1319

62. FISH PLATES AND FISH BOLTS
 No of fish plates per km = 2 x no of rails per km = 2 x 157 = 314.
 No of fish bolt = 4 x no of rails per km = 4 x 157 = 628
 No of bearing plates = no of sleepers x 2 = 2 X 1319 = 2638 Nos.
DOG SPIKES
No of fog spikes per km of the track = 4 x no of sleepers
= 4 x 1319 = 5276.

63.  The construction of new railway track is studied in three stages:
1. First stage------Earthwork (formation and consolidation)
2. Second stage-------Plate laying (laying of a railway track)
3. Third stage-----Laying of ballast on the track

64. The tasks involved in construction of new railway line are:
 Land acquisition
 Earthwork and bridges
 Construction of station building, staff quarters and other allied
facilities including platforms and sheds.
 Laying of plates including ballasting of track
 Opening of the section to the traffic

65. LAND ACQUISITION:
 The work should start well in advance so that all legal and
financial formalities are completed in time and the possession of
the land is taken for starting construction work.
 Done with the help of state government as per the procedure laid
down in the Land acquisition act (section 4-6).

66.  Land acquisition is done after giving a certain notice and paying
the requisite compensation.
 In case of emergency, it is done by special sections 9 and 17 of
Land acquisition act.
 The land being acquired should be sufficient for the formation,
berm and borrow pits.
 It should also have adequate provision for any future expansion.

67. EARTHWORK AND FORMATION:
 Based on rail level, the formation may be embankment or cutting
 Embankment is generally preferred because of good drainage
 Height of embankment depends on High Flood Level (HFL) and
free board.
 For BG track = 6.10m (single line), 10.82m (double line)
 Earthwork is normally done in 30cm layer for well compaction
of soil

68.  Shrinkage allowance of 5% is made for consolidation of the
final cross section ( in case of mechanical compaction).
 Blanket thickness 30cm is provided on the top of the
embankment.
 The economical limit of moving the earth in the longitudinal
direction is determined by the Mass-Haul curve.
 Tenders are separately invited for each zone so that work can
progress simultaneously in all the zones.

69. PLATE-LAYING:
 The operation of laying out on the prepared formation of railway
and connecting up of the rails and sleepers is termed as plate-
laying.
 Plate laying operations do not include the placing of the ballast.
 The point upto which the new track has been laid is known as rail
head and the point from where the laying is commenced is
known as the base.

70. Methods of Plate-laying:
TRAM LINE METHOD:
Used in flat countries. Progress of the work per day is 1-
61kms.
Materials are collected either by as service road laid parallel
to the track is prepared and the materials are transported in
lorries or bullock-carts to the site of work

71.  Or a temporary line known as tram line is laid parallel to the
track and the materials are carried in the wagons.
TELESCOPIC METHOD:
Widely used in India. In this method, the materials are
transported in material trains to the farthest point of the new track
and unloaded. These materials are then carried by the rail-head and
different components of the track assembled here.

72. Operations in telescopic method:
 Collection and preparation of materials at depot
 Transportation of the materials from the depot to the work site
 Unloading of materials at the worksite and carrying them to the
rail head.
 Fixing the rails to the sleepers and joining the two rails with fish
plates
 Packing of the track for correct level and alignment

73. AMERICAN METHOD: In this method, rails and sleepers are
assembled at the workshop and then, the complete sets are moved
to the site of work. Suitable cranes also accompany these acts. The
following procedure is adopted:
1. The complete sets of rails and sleepers along with the
cranes come in one train to the rail head.
2. One set is unloaded and it is linked with the rail head
3. The train moves ahead by one rail length
4. The procedure is repeated.

74. Relaying of track:
 Changing of rails, sleepers and fittings in continuous lengths is
known as relaying of track and it becomes necessary under the
following circumstances.
 Existing track is to be replaced by heavier sections due to
increased intensity of traffic and higher axle loads.

75.  Old but serviceable materials of mainline or to be used for
laying a new branch line and then the mainline are to be provided
with the new track materials.
Methods of relaying a track:
1. Relaying of double or multiple track
2. Relaying of singe line track
3. Standard method of relaying

76. Relaying of double or multiple track:
 The best method is to divert all the trains from one track to the
other track.
 Track can be relayed by dismantling
 For diversion of traffic, two temporary cross overs, between the
track to be relayed and the adjoining track are provided.

77. Relaying of singe line track: It can be done by several methods
such as,
1. Diverting the existing track by few centimetres sideways and
interlacing the new track with the existing track.
2. First interfacing new sleepers and subsequently renewing the
rails.
3. Renewing the rails and sleepers as two independent operations
i.e. the new rails are first fixed with old sleeper and then old
sleepers are replaced by new ones.

78. Standard method of relaying
 The relaying of the track may be divided into three operations:
1. Preliminary work
2. Actual relaying of the track
3. Consolidation of relayed track and removal of released
materials.

79. Preliminary work:
 Installation of caution signals 400m beyond the section to be
relayed.
 Speed limit boards
 New materials are distributed along one side of the track
 Two fish bolts are removed and oiled and refixed at all the joints
 The position of sleepers is marked on new rails

80. Actual relaying of track:
 Remaining fish plates, fish bolts and other track fittings are
removed.
 New sleepers are laid on the levelled ballast bed
 Joints are squared, gauge is corrected and the gauge rail is fixed
by means of spikes.
 The track is then properly aligned and alternate sleepers are
packed.

81. Consolidation of relayed track and removal of released materials:
 The remaining fish bolts and fittings as well as the remaining
sleepers are properly inserted and fixed.
 New ballast is distributed on the track
 New ballast along with the old screened ballast is used for
packing the track by means of beater-cum-pick axe.
 Speed limit is gradually lifted with the time of settlement
 The released materials are used for branch line, a loop or a
siding.

82. Track drainage involves the interception and removal of
water from, upon or under the track and is accomplished not only
by surface interception and drainage arrangements, but also where
necessary by a sub-surface-drainage system.
 Sources of moisture in a railway track:
1. Surface water due to rain, dew or snow
2. Moisture sucked by capillary action
3. Seepage water from adjacent areas
4. Hydroscopic water or held-water
5. Rain water surface

84.  A good track drainage system should essentially ensure that no
water percolates into the track at either the surface or the sub-
surface levels.
 The efficiency of a modern track depends upon the strength and
stability of the formation which in turn depends upon the good
track drainage.

85.  Drainage of a track, Station Yards and platforms are the three
places Where Drainage arrangements are needed.
 Track Drainage Comprises of Interception, Collection and
disposal of from the track.
 This is done by adopting proper Surface and Subsurface
Drainage System

86. Surface drainage:
 Surface water due to rain, snow or from adjacent areas should be
drained off properly by designing well-planned and effective
surface drains.
 For bank and formation, good quality soil having well graded
particles and high internal friction should be used. The soil
should not swell or shrink with variation in moisture content.

87.  The surface water is first collected in well designed side drains
and cross-drains which is further disposed off at the nearest
stream or natural water course.
 Cross drainage structures like culverts and bridges may be
necessary for disposing of the surface water.
 Surface Water due to rain or Snow or Flow From Adjacent areas
have to be Disposed of Through Surface Drainage.

88. 1. Surface Drainage has to be attended to in three locations.
Drainage in mid- Section Between railway Stations
1.Drainage in mid-section
2.Drainage in Station Yards
3.Drainage at Station Platforms

89. 1.Drainage in mid-section:
 A typical arrangement of cross Section of a mid-section. Side
Drains may be unlined or lined.
 At a level Crossing all water should flow to the side Drains.
 In cutting catch water Drains Have Been Provided Wherever
Necessary.

90.  All Extra Ballast on the Side Should be Recovered Which
Encourage Growth of the vegetation.

91. 2.Drainage in Station Yards:
 Open Surface Drains-Shaped Drains, Longitudinal Drains and
Open Drainage are Provided to Free Station Yard From Water .
 A typical surface drainage system with open Drains for a Station
Yard .
 Every Station Yard is Provided with a network of Cross and
Longitudinal Drains.

92.  In Station Yard the vulnerable points are water columns and
carriage watering points with washing Hydrants.
3.Drainage at Station Platforms:
For Drainage of Station Platforms the following Points
Should be Taken into account
1.Slopes away From the track
2. Discharge on non-Track Side

93. 3. Discharge not towards Ruin-through lines
 In general all end of platforms should be sloped away From the
Track. All other Discharges Form tea Stalls, Toilets, Water taps.
If there is need be , covered longitudinal Drains Should Be
Provided
 In case of island platforms, all Drains Should discharge on the
less important side of the track

95. 2.Sub-Surface Drainage:
 Sub-surface water is due to the capillary water.
 Other sources are seepage from adjacent areas percolation of rain
water.
 The sub grade and the formation are immediately affected by the
Sub-Surface irrigation,
1. Provision of an inverted fillers
2. Sand piling
3. Laying of Geotextiles
4. Other Methods

96. 1. Provision of an inverted fillers:
 An inverted filter blanket of adequate thickness is provided
between the ballast and the week formation.
 The Blanket is of non-Cohesive material with enough bearing
capacity to sustain the load thereon.
 The inverted fillers Blanket is a very effective method of
improving the bearing capacity.

97.  It serves as a porous medium to drain off the Surface Water and
Serves as a barriers for the upward movement of fine Grained
particles.

99. 3. Laying of Geotextiles:
 Geotextiles are made of polymers which are Extensively as a
new Technique in improving the Soil Properties and Drainage
 On Indian railways Geotextiles are Extensively used.
 Geotextiles are having the unique property to allow water to pass
through but not the soil fines.

100.  They not only Work as separate and filters But also as
reinforcement bed
 Geotextiles are either laid directly below the ballast or sandwich
between a 50mm layer of sand on top and a 25mm layer sand
below so that the ballast directly does not rest on Geotextiles .
and thereby preventing tear and puncture of textiles

101. 4. Other Methods:
 All other methods Which are used to for Soil Stabilization may
be used to arrest Sub-Soil water, Cement Grouting, Chemical
Grouting.

104. Objectives of maintenance of railway track:
1. The strength of track structure goes on reducing due to high
speed of heavy axle loads and repetition of loads.
2. The track structure is subjected to other deteriorating effects
like rain water, of sun and wind. The wear and tear of rails and
rolling stock is bound to take place.
3. The track structure has to bear so many other curvatures, speed
and load particularly on curves, points and crossings.

105. Advantages of good maintenance:
1. The life of both track as well as of rolling stock increases.
2. The journey becomes easy and comfortable.
3. Increase in safety.
4. Saving in operating costs as fuel consumption is less.
5. Safety of passengers and goods encourages more and more use
of railway.
6. Higher speed of trains is achieved.

106. Types of maintenance:
1. Daily maintenance
2. Periodical maintenance

107. Daily maintenance: Maintenance is carried out by the full time staff
maintained throughout the year. The use of maintenance gangs, all
along the railway track, is made. The railway track is divided into
suitable sections 5 to 6 km length.
1.To check the bolts of fish plates and tighten it if necessary.
2.To check the rail gauge
3.To check the joints
4.To check the fittings of sleepers and rails

108. Periodical maintenance: Periodic maintenance is carried out after
an interval of two to three years.
1.Levelling of rails 2.Track alignment
3.Gauge 4.Proper drainage
5.Track components 6.Bridge and its approaches
7.Rolling stock 8.Points and crossings

109. The railway track should be maintained properly in order to
enable trains to run safely at the highest permissible speeds and to
provide passengers a reasonable level of comfort during the ride.
Track maintenance becomes a necessity due to following reasons.
1. Due to the constant movement of heavy and high-speed trains,
the packing under the sleepers becomes loose and track geometry
gets disturbed.

110. 2. Due to the vibrations and impact of high-speed trains, the fittings
of the track come heavy wear and tear of the track and its
components.
3. The track and its components get worn out as a result of the
weathering effect of rain, sun, and sand.
Railway tracks can be maintained either conventionally by
manual labour or by the application of modern methods of track

111. maintenance such as mechanical tamping or measured shovel
packing.
Conventional methods: As per the timetable or calendar, the 12-
month cycle of maintenance consists of the following operations.
(a) Through packing
(b) Systematic overhauling
(c) Picking up slacks

112. a.) Through packing: The process in through packing
 Opening of road
 Examining of rails, sleepers and fastenings
 Examining Squaring of sleepers
 Check for alignment
 Check for the gauge of the track
 Tolerance for gauge error was 6mm for straight tracks

113. b.) Systematic overhauling: The systematic overhauling of the track
should normally commence after the completion of one cycle of
through packing. It involves the following operations in sequence.
 Shallow screening and making up of ballast section
 Replacement of damaged or broken fittings
 All items included in through packing
 Lubrication of rail joints

114. c.) Picking up slacks: Slacks are those points in the track where the
running of trains is faulty or substandard.
(a) Stretches of yielding formation
(b) Poorly maintained sections that have loose packing, bad
alignment, and
(c) Improperly aligned curves
(d) Approaches to level crossings, girder bridges, etc., particularly
in sags
(e) Portions of track with poor drainage
(f) Sections with an inadequate or unclean ballast cushion

115. Modern methods: Modern methods of track maintenance employ
track machines and other modern track equipment for the
maintenance of tracks as opposed to the traditional methods of
manual packing. The methods used generally are the following.
(a) Mechanized maintenance of track with the help of track
machines
(b) Measured shovel packing (MSP)
(c) Directed track maintenance (DTM)

116. A railway station or a railroad station and often shortened to
just station, is a railway facility where trains regularly stop to load
or unload passenger sand/or freight

117.  Purpose of Railway station
 For exchange of passengers and goods.
 For control of train movements
 To enable the trains on a single line track to cross from opposite
directions.
 To enable the following express trains to overtake
 For taking diesel or coal and water for locomotives

118.  For detaching or attaching of compartments and wagons
 For sorting of bogies to form new trains, housing of locomotive
in loco sheds.
 In ease of dislocation of track due to rains, accidents etc...
 For repairing engines and changing their direction
 Railway station are having suitable approach roads from
surrounding areas.

119.  Wayside Stations
 Junction Stations
 Terminal Stations
Classification of Stations:
Stations can be classified on the basis of their operation as
1.Block stations-Class A, Class B and Class C
2.Non Block Stations-Class D stations or Flag stations
3.Special class stations.

120. Wayside Stations: In this type arrangements are made for crossing
or for overtaking trains. Wayside stations are of the following
types.
i. Halt stations
ii. Flag Stations
iii. Crossing stations

121. HALT STATION: A halt, is a small station, usually unstaffed and
with few or no facilities. In some cases, trains stop only on request,
when passengers on the platform indicate that they wish to board,
or passengers on the train inform the crew that they wish to alight.

122.  Flag stations: describes a stopping point at which trains stop
only on an as-need or request basis; that is, only if there are
passengers to be picked up or dropped off.
 These stations have no overtaking or crossing facilities and
arrangements to control the movement of trains. These stations
have buildings, staff and telegraph facilities.
 Some of the flag stations have sidings also in the form of loops.

124. CROSSING STATIONS:
 Provided with facilities for crossing
 In this type at least one loop line is provided to allow another
train if one track is already occupied by a waiting train
 Generally the train to be stopped is taken on the loop line and the
through train is allowed to pass on the main line

126. Junction stations: At a junction stations, lines from three or more
directions meet. The stations where a branch line meets the main
line are known as junctions.
Arrangements in junction stations:
 Facilities for interchange of traffic between main and branch line
 Facilities to clean and repair the compartments of the trains
 Facilities for good sidings, engine sheds, turn table etc.

128. Terminal Stations: It is a station where a railway line or one of its
branches terminates.

129. Block Stations: The stations at the end the block sections are
called Block stations.
 Authority to proceed is given in the shape of token at these
stations.
 Class A Station
 Class B Station
 Class C Station

130. Non Block Stations:
 Also known as Class D station or Flag station
 Situated between two consecutive block stations
 May not be telegraphically connected to the adjacent stations
 No equipment or staff is provided for controlling the movements
of the trains.
 Trains are stopped by flag signals only

131. Special class stations: Stations not coming under block station and
non block stations are called special class station.

132.  An area consisting of a network of railway tracks, sidings, and
sheds for storing, maintaining, and joining engines and carriages.
 A yard is defined as a system of tracks laid within definite limits
for various purposes such as receiving sorting and dispatch of
vehicles.

133. Types of yards:
 Passenger yards
 Goods yards
 Marshalling yards
 Locomotive yards

134. Passenger yards: Function of passenger yard is to provide all the
facilities for the safe movement of passengers.
Facilities in passenger yards
 Booking office, enquiry office, luggage booking room, cloak
room and waiting room for passengers
 Parking space for vehicles
 Signals for reception and dispatch of trains

135.  Platforms and sidings for shunting facilities
 Facilities for changing batteries
 Facilities for passing a through train
 Washing lines, sick lines facilities

136. Goods yards:
 A goods station(also known as a goods yard, goods depot or
freight station) is, in the widest sense, a railway station which is
exclusively or predominantly where goods (or freight) of any
description are loaded or unloaded from ships or road vehicles
and/or where goods wagons are transferred to local sidings.
 These are provided for receiving, loading and unloading of goods

137. Requirements of a goods yard:
 Approach road for movement of goods
 Sufficient number of platforms for loading and unloading
 Sufficient number of godowns
 Booking office
 Cart weighing machine
 Cranes for loading and unloading

138. Marshalling yards:
 Marshalling yard is a rail road yard found at some freight train
stations, used to separate rail road cars on to one of several tracks
 It is the place where goods wagons received from different
centres are sorted out and placed in order to detached at different
stations
 The marshalling yards are distribution centres
 Empty wagons are also kept in marshalling yards

140. Factors for the efficient functioning of marshalling yards:
 Shunting operations should not disturb the regular trains
 Should be kept parallel to the running trains
 Movement of wagons in one direction only
 Repair facilities should be provided on one or more sidings
 Connected to all important railway stations
 Goods yard should be nearer to the marshalling yard

141. Types of marshalling yards:
(i)Flat yard
(ii)Gravity yard
(iii)Hump yard

142. Flat yard: Flat yards are constructed on flat ground, or on a gentle
slope. Freight vehicles are pushed by a locomotive and coast to
their required location. A flat yard has no hump, and relies on
locomotives for all car movements.

143. Gravity yard: The whole yard is set up on a continuous falling
gradient and there is less use of shunting engines.
 Typical locations of gravity yards are places where it was
difficult to build a hump yard due to the topography
 Gravity yards also have a very large capacity but they need more
staff than hump yards and thus they are the most uneconomical
classification yards.

144. Hump-yard:
 These are the largest and most effective classification yards, with
the largest shunting capacity—often several thousand cars a day.
 The heart of these yards is the hump: a lead track on a hill
(hump) that an engine pushes the cars over.

145.  Single cars, or some coupled cars in a block, are uncoupled just
before or at the crest of the hump, and roll by gravity onto their
destination tracks.
 A hump yard has a constructed hill, over which freight cars are
shoved by yard locomotives, and then gravity is used to propel
the cars to various sorting tracks

147. Locomotive yards: This is the yard which houses the locomotives
for various facilities such as watering, fuelling, cleaning, repairing,
servicing etc.

149. Requirements of a locomotive yard: Should be located near the
passenger and goods yards
 Water column
 Engine shed, Ash pit, inspection pit, repair shed, turn table
 Hydraulic jack for lifting operations
 Over head tank and loco well
 Sick siding
 Place for future expansion

150.  A buffer stop or bumper is a device to prevent railway vehicles
from going past the end of a physical section off-track
 The design of the buffer stop is dependent in part upon the kind
of couplings that the railway uses, since the coupling gear is the
first part of the vehicle that the buffer stop touches