Railways, Bridges and Tunnels
QUESTIONS 2023-2024
Assignment I dated 03-10-2023
{IMPORTANT}
SECTION {A} RAILWAY’S
NOTE:- UPDATE YOUR PRESENTATIONS WITH DIAGRAMS WHERE APPLICABLE DON’T WASTE TIME MAKE IT ROUGHLY
I:-Corrugated and Roaring Rails
In some places, the rail heads are not straight but corrugated, ie a single hard surface. Such rails are known as corrugated rails and roar when vehicles pass over such wavy rails and hence such rails are also called roaring rails.
The occurrence of a wave on a rail is very complex and therefore it is not possible to mention specific reasons for it. However the following are the possible factors which are:
1. Engine wheels,
2. Excessive slope or extremely tight gauge,
3. High speed of trains,
4. Using a wooden sleeper
5. The presence of high humidity and dust in the atmosphere,
6. Rigid railway track,
7. Slipping of the wheels of the engines
8. Due to damping in tunnels
9. Soft and yield construction, steep gradient, sudden application of brake, 10. Use of lightweight wagons and coaches,
11. Use of steel with high nitrogen content and high tensile strength;
12. Soft ballast, vibration during rolling of the rail section, Wavy rail tracks are commonly found at the following locations:
1. Wavy rails are found in long tunnels,
2. At the starting and stopping points of trains, the wavy rail is visible.
3. On an electrified section of a railway track, railroads developed a railroad track.
4. If the ballast used for railway tracks contains broken bricks, there is a possibility of development of wavy rail.
Due to the wavy rail on the railway track causing inconvenience to the passengers and this requires more maintenance attention. Moving the train on the walled rail will cause the slipping o the railway track to cause the slack of the; hostages to move the ballast base from its place. And sleepers are in danger of moving from their places. That is, due to heavy rail, various components of the railway track have a very bad effect. Due to this, maintenance of engine qood coaches cost 10% more on maintenance of railway track and consumption of fuel
II. Maintenance of Railway Tracks tools:-
Measuring equipment
Rail gauge: To check the gauge
Straight edge and spirit level: To check the alignment as well as the cross level
Gauge-cum-level: To check the gauge as well as the cross level
Cant board: To check the difference in cross levels or the superelevation of the sleepers
Mallet or wooden hammer: To check the packing
Canne-a-boule: A modern equipment used to assess the voids under the sleepers
T-square: To check the squareness of sleepers
Stepped feeler gauge: To measure wear or clearances
Maintenance tools
Sleeper tong: To carry sleepers
Rail tong: To lift and carry rails Beater: To pack ballast under the sleeper
Crowbar : To correct track alignment and to lift the track for surfacing. Clawed crowbar are
used for taking out dog spikes.
Jim Crow: To bend or break the rails
(a) Spiking hammer: To drive spikes
(b) Keying hammer: To drive keys
Spanner: To tighten bolts
Wire claw or ballast rake: To draw or pull out ballast while screening, packing, etc.
Phowrah (shovel): To cut earth or to pull out ballast
Auger: To bore holes in wooden sleepers
Box spanner: For driving rail screws or plate screws
Wire basket: For screening the ballast
Pan iron motor: For leading earth/ballast
III:-Objectives of Maintenance of Railway Track
The strength of track structure goes on reducing due to high speed of heavy axle load and repetition of loads.
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.
The track structure has to bear so many other curvatures, speed and load particularly of curves, points and crossings.
Advantage of Good Maintenance
The life of both tracks as well as of rolling stock increases.
The journey becomes easy and comfortable.
Increase in safety.
Saving in operating costs as fuel consumption is less. Higher speed of trains is achieved.
The types track maintenance:- Track Maintenance makes sure that the track is safe to use and that there no problems.
IV:-Types of Maintenance
Daily maintenance
Periodical maintenance-
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 5-6 km in length.
To check the rail gauge.
To check the joints.
To check the fittings of sleepers and rails.
Periodical Maintenance
Periodic maintenance is carried out after an interval of two or three years.
Levelling of rails
Track alignment
Gauge
Proper Drainage Track Components
Points and crossings
V:- General maintenance of railway track..
In general, Maintenance of railway track is to take periodic repairing, mainly including periodic updating, periodic comprehensive maintenance, regular inspection and key repairing track.
1. Rail grinding: This consists of grinding machines travelling along the track grinding stones, which are rotating stones or stones oscillating longitudinally, to abrade surface of rail. Rail grinding is conducted to correct rail corrugations, fatigue and m flow and to re-profile the rail.
2. Rail replacement: This may be conducted to upgrade the track to a higher gauge or to replace the same gauge rail due to defects, wear or derailment damage.
3. Tamping: This is conducted to correct longitudinal profile, cross level and alignment of track. A number of sleepers at a time are lifted to the correct level with vibrating tamping tines inserted into the ballast
4. Track stabilization: Track stabilizers vibrate the track in the lateral direction with a vertical load to give controlled settlement. Tamping and compacting ballast underneath sleepers reduces the lateral resistance of the track. Track stabilization can restore the lateral resistance to the original level.
5. Ballast injection (stone blowing): Ballast injection, or stone blowing, is conducted to correct longitudinal profile. The process introduces additional stones to the surface of the existing ballast bed, while leaving the stable compact ballast bed undisturbed.
6. Sleeper replacement: In almost all types of sleeper defects, remedial action is not possible and the sleeper requires replacement. Defective sleepers can result in the rail losing the correct gauge, which can cause rolling stock derailments.
KEEP CHECKING FOR UPDATE’S OF OTHER SUBJECT’S AS WELL
SECTION {B} BRIDGE’S
I:- Temporary bridge
Bridges that are built for a particular situation or occasion and are considered unusable when the objective is fulfilled are called temporary bridges.
It costs a lot to build a permanent bridge, so temporary bridges are built to cross the rivers. They are used throughout the year except the rainy season. These wooden empty drums are made from steel caps, iron pipes, boats etc. and can be aged from 5 to 10 years. They are constructed for light traffic, they are simple and cheap to make. They are also used for maintenance.
Temporary bridges are constructed to meet the following requirements:
1. When bridge is required for temporary or short duration.
2. When necessary money, time and skilled craftsmen are not available for construction of permanent bridge.
3. When it is not considered appropriate to build a temporary bridge in that area either for the security of the country or from the military point of view.
4. When the topography of the area, river bed, flow etc. are not found suitable for permanent bridge constructions
5. When construction materials and other means for permanent bridge are not available,
6. When there is very less traffic on the road and it is also light type.
Bridges are of the following types according to the materials used in the construction of bridges
1. Timber Bridge
2. Masonry bridge
3. Steel Bridge
4. Reinforced pre-reinforced cement concrete bridge
Timber bridge: Wood is used in the construction of less important bridges, the wood used for this is free of cracks of good quality, free of lumps and well ripened. They are used in places where wood is available and available cheaply.
The length of wooden bridges should not exceed 45 meters. Wooden bridges are very weak at thrust, so special attention is given to joints. But when constructing wooden bridges, the safer index is taken from four to five as they are much weaker than the added steel flowers. There is a fear of fire and termites in the wood and due to the effect of the environment, they start getting destroyed.
Masonry Bridge: Brick masonry or stone masonry is commonly used in the construction of dots for medium-term bridges. Good cement spices employ masonry. Since masonry is weak in tension, it is checked that no stress develops in any part of the dot under the worst combination of fixed load and moving load. The brick used for brick masonry should be well-baked, free of cracks sharp and square-edged. They should be uniform in shape and give a clear ringing sound while colliding with each other. They should be soaked in water well before their use.
Similarly, the stones used in masonry are also hard, durable, and capable and of uniform size they are soaked in water before use.
Steel bridge: In view of the strength and durability of steel, the use of steel as construction material in the construction of a bridge is considered to be good. The steel bridge also known as steel dharnapul or plate Girder Bridge or truss bridge. Steel bridges are used in highways and railways. Steel bridges are used extensively in railways in India and slabs of cement concrete are made in steel bridges used in roadways. The steel bridge is easy to construct but there is a fear of rust.
Reinforced and pre-reinforced cement concrete bridge
Reinforced cement concrete is highly used in the construction of bridges at the present time. Masonry bridges are weak in tension and reinforced concrete bridges are used for tension in structure. Pools of pre-inclined concrete are highly formed at this time. This bridge is used high-strength steel. Pre-concrete concrete bridges are more efficient than normal concrete bridge
Pre-Stressing of steel enables it to work at high stress levels and pre-compressive concrete reduce its cracks.
II: Abutments
The end support of a bridge super-structure is known as an abutment.
1. An abutment is provided for the following three purposes:
1. To finish up to bridge so that it can be put for use,
2. To retain the earth filling, and
3. To transmit the reaction of super-structure to the foundations. Types of abutments: The abutments are classified in the following two ways:
. According to the layout in plan
2. According to the type of super-structure
3. According to the layout in plan:
The abutments may be with or without the wing walls. When the abutments are with wing
walls, they may be of three types.
1. Abutment with straight wing walls.
2. Abutment with splayed wing wall.
3. Abutment with return wing wall.
Pier and write its classification
The intermediate supports of a bridge super-structure are known as the piers. Function: The only purpose of providing piers is to divide the total length of bridge into suitable spans with minimum obstruction to the stream or river.
Types of piers: Following are the usual types of the bridge piers:
(1) Column bents
(ii) Cylinder piers
(i) Dumb-bell piers
(iv) Pile bents
(V) Solid piers
(vi) Trestle bents.
Column bents: A column bent type of pier is adopted, if the longitudinal beams or girders tane consisting of vertical members and braces. The transverse beams are provided to support of the super-structure of bridge are closely spaced. The term bent is used to indicate a supporting the longitudinal beams and two or more columns on a solid foundation are constructed to support The Walsverse beams as shown in fig. The pockets formed between the longitudinal beams may be wed to carry gas pipes, sewage pipes or water pipes. The column bents are lighter than the Baby piers and are used for continuous spans.
Cylindrical Pier’s
Pile Bent’s REFER WITH FIGURE & SHORT NOTE’S
Trestle Bent’s
Maintenance of the Bridges
Following are the general works of maintenance for the bridges:
(1) Any signs of movement of the bricks or stones in masonry work should be carefully watched.
(2) The flood training bunds will have to be constructed and maintained in case of some
rivers.
(3) It should be seen whether the masonry has washed, cracked deteriorated. The cracks developed in the masonry will have to be examined carefully to see whether they are superficial or due to structural failure or defect.
(4) The suitable pitching is to be provided to the embankments near bridges.
(5) The bearings of girders should be coated with oil from time to time.
(6) The bed blocks should be inspected from time to time and the necessary repair should be immediately carried out.
(7) The floor system of approaches and bridges should be properly maintained.
(8) The movement of foundations, if any, should be carefully inspected and all attempts should be made to stop such further movement.
9) The rivets should be carefully inspected at regular intervals and all defective rivets should be punched off and replaced.
(10) The soundings are to be taken in the river bed and depth of scour near the abutments and piers is to be detected.
general maintenance works for steel and concrete bridges.
Cracks in concrete :
The cracks in concrete can be due to the following reasons:
(1) Due to absence of expansion joints.
(2) Due to lack of water tightness, the mortar may crumble.
(3) Due to insufficiently strong bricks or stones, surface may break
(4) Due to excess water used in concrete mix.
(5) Due to inadequate cover to the reinforcement.
(6) Due to fatigue, some components of the steel structure may develop cracks.
Rectification:
(1) The bearing area should be kept thoroughly cleaned. (2) Any crack of structural significance should be sealed by the pressure grouting or other means.
3) The weep holes should be kept in working condition.
(4) The obstructions causing a scour in river should be removed.
Corrosion of structural steel work: The steel structure or structural steel of a bridg requires constant attention as it is liable to corrode due to weathering action. The structure may become weak if this problem is not promptly attended. The structural steel should be properly embedded in the concrete to prevent corrosion. The rate of corrosion of steel depends upon the quality of concrete, depth of cover provided below reinforcement and degree of quality control. No concrete is made absolutely impermeable to water air. For highway bridges, dense concrete prepared from ordinary Portland cement is found quite impermeable to provide adequate protection to steel. Also, the drained water falling on a structural part of a bridge may cause deterioration of structural steel. Tunnels
Rectification :
The super-structure of steel bridges should be periodically cleaned and painted. Clearance between steelwork and brickwork should be provided.
Adequate To prevent rusting of the hidden parts, thicker sections should be used instead of thinner sections while designing.
Sufficient numbers of drainage holes should be provided to avoid collection of rain and dirt at through sections.
INSPECTION OF BRIDGE’S
It is absolutely necessary that every part of the bridge structure is kept under constant observation. For this purpose, a periodic or routine inspection followed by detailed technical examination, wherever necessary, is essential. The technical inspection, should be entrusted to specially selected and trained personnel. Thus the above-mentioned maintenance works can broadly be grouped into the following two categories:
Detailed inspection.
Routine inspection.
Detailed inspection: The detailed or in-depth inspection involves the visual examination of all super-structure and sub-structure elements. It is carried out in the following two categories: General: A check-list of items is inspected either visually or with the aid of standard instruments in the general inspection. It is carried out once in two years.
Major It requires close examination of elements with the aid of access facilities. It is conducted at intervals of 5 to 6 years or even at smaller intervals depending upon the design a the structure. The structural analysis of bridges is done by experienced bridge design engineer soon after the occurrence of calamities such as floods and earthquakes or the passage of high intensity loadings.
The trouble spots to be checked up during the detailed inspection are as follows:
1. behaviour of expansion joints;
2. cracks in metalwork;
3. damaged structural members;
4. Deterioration and cracks in concrete;
5. Excessive vibrations;
6. Foundation settlement and movement;
7. indiscriminate past repairs;
8. Inoperative expansion bearings
9. Loose connections
Routine inspection: The routine inspection aims to look after the general examination
Structure at regular intervals and the spots having outward physical defects are immediately
Repaired. The routine inspection is generally applicable to short span bridges. The inspection is conducted prior to the monsoons and the data and details are recorded in proforma. A post-monsoon inspection is also conducted in order to compare the data an deterioration.
The main parts of the bridge should to be inspected as follows during detailed inspection
1. Inspection for differential settlement.
2. Examine the effects of scouring or silting.
3. Appearance of structural cracks in the foundation masonry.
4. Check about scouring of foundation soil below abutment and pier.
5. Inspection about any scouring has taken place below abutments, piers, wing wall not.
6. Check if masonry work in sub-structure is done with proper pointing or not.
7. Weather weep holes provided in the abutment and wing walls are open or not.
8. Structural steel work is properly painted or not.
9. Check weather expansion joints are properly done or not.
10. Check for painting work to steel work and corrosion of steel.
11. Check brickwork and concrete work if any cracks are developed or not.
12. Inspect the parapet wall and its railing.
Deterioration of Bridges
The bridge deteriorates due to following factors:
(1) Defective design of bridge.
(2) Due to contact of water at various parts of a bridge, corrosion, erosion, scorin take place.
(3) Resistance to weathering effects.
(4) Wrong or incomplete information about the bridge design
(5) Temperature changes.
(6) Negligence to minor effects.
(7) of heavy vehicles which are not considered for the design load.
(8) Poor quality of construction materials.
(9) Poor quality of workmanship.
(10) Natural hazards like cyclone, earthquake, flood, tsunami, etc.
SECTION {c} Tunnel’s
Ventilation in tunnels:- Maintaining the circulation of pure air during and after construction in the tunnel is called tunnel ventilation. The ventilation given during tunnel construction is called temporary ventilation and the ventilation given after tunnel construction is called permanent ventilation. During various operations in the tunnel, the effluent is also released from the gas which is required to be taken out of the tunnel otherwise. These contaminated gases cause inconvenience to the workers and passengers travelling.
purpose and requirements of tunnel ventilation.
There are four main objectives of tunnel ventilation.
1. To provide clean air to the workers working in the tunnel.
2. Removal of dust emitted during blasting and mucking.
3. The lever released during detonation releases the harmful gases.
4. Maintaining proper temperature in deep tunnels.
Requirements of tunnel ventilation: The following requirements have to be met for a good tunnel ventilation.
Dust and gases from the work place should be cleaned as soon as possible so that work can continue without any delay.
2. The amount of dust released at the time of color formation should be only to the required safe limit.
3. Clean air should be operated without any obstruction throughout the length of the
tunnel.
4. The tunnel should have a system to prevent harmful gases at reasonable distances.
methods of ventilation /types of ventilations
There are two methods of tunnel ventilation
1. Natural ventilation
2. Mechanical ventilation
Natural ventilation: Natural ventilation is achieved due to the difference in temperature inside and outside the tunnel. By providing the shaft at a suitable interval along the alignment of a tunnel during its construction, natural ventilation can be achieved. This method is effective in the following situations:
1. In the construction of a 100 m long tunnel with a straight slope made of straight length.
2. When a drift operates from portal to portal, it provides natural ventilation operation.
3. When the orientation of the tunnel is along the wind direction. 4. When the tunnel is small and its diameter is large.
For long tunnels, natural ventilation is insufficient and, therefore, mechanical ventilation
Becomes necessary.
Mechanical Ventilation
Mechanical ventilation is provided in case of natural ventilation and satisfactory conditions. One or more electric fans or blues are employed in the mechanical method to remove harmful gases from the tunnel and flow into the clean air tunnel.
The tunnel has the following three systems of mechanical ventilation :
1. blowing or plenum{ n building construction, a plenum (pronounced PLEH-nuhm, from Latin meaning full) is a separate space provided for air circulation for heating, ventilation, and air-conditioning (sometimes referred to as HVAC) and typically provided in the space between the structural ceiling and a drop-down ceiling}process
2. Exhausting or vacuum process
3. Combined of blowing and exhausting process
Blowing or plenum process: In this system, the contaminated air exits the tunnel itself and with the help of a clean air bolero is sent through a pipe. Due to which clean air is available in the work area. This method is not suitable in long tunnels. In this, dust and gas slowly come out of themselves, which creates a fog inside the tunnel, which makes it difficult to see far at work.
Exhausting or vacuum process: In this system, the contaminated air from a duct that is fitted with a vacuum evacuator keeps the brides out. Get out. However, in this system, uniform homogeneity is not possible inside the tunnel. Penetration interests inside are heavy due to exposure to clean air and moisture and affect the condition of the workplace. These systems are not suitable for long tunnels.
Combined of blowing and exhausting process: In this system both the above systems are adopted so that the contaminated air is dust and gas is taken out and clean air keeps coming to the workplace. After the blast operation, the removal process is carried out for the first 15 to 30 minutes to remove contaminated gas, dust in the tunnel. Accordingly air valves are used during large two inlet valves are closed and exit valves OPENED as a exhaust
Dust control in tunnel
During the tunnelling, some of the major tasks such as drilling explosives and removal of colourless debris are caused by swinging inside the tunnel, which makes it difficult for the workers to breathe at the workplace and there is a possibility of many diseases hence dust from inside the tunnel The following measures are taken to reduce and avoid it quickly.
1. Wet drilling
2. Use of vacuum hood
3. Use of a respirator
Wet drilling: In order to keep the water sprayed in the holes at the time of drilling, modern handling machines are provided with water spraying. Keeping images dropped reduces e possibility of dust blowing and also keeps the bit cool. It is highly used. The amount of water the pictures depends on the type of drilling used and the speed of drilling.
Use of vacuum hood: It is fitted with steel hoods around the beat which are connected an exhaust pipe from which dust is pulled out. This method is suitable for wet drills.
Use of respirator: At the time of tunnel cutting, workers are provided with breathing devices which make it easier for the workers to breathe and the dust does not get in but these instruments These are expensive so they cannot be used at all places
Lights used in the tunnel
If there is not enough light in the tunnel, then there is a lot of processes that cannot be e properly, so proper lighting should be provided in the tunnels. In the area of drilling and of debris in the tunnel, there should be proper lighting at the bottom, of the shaft, at the material storage site, at the pumping station, etc. And there should be adequate lighting at the time of operation of the tunnels.
Following are some major things related to lighting:
1. Light intensity should correspond to tunnel work
2. For lighting to be arranged in more than one place.
3. Instead of giving more amount of light at one place, lighting should be arranged at appropriate places at certain intervals.
4. The cards used for transportation of material and debris should have lighting arrangement.
5. Bulbs or other lighting devices are installed in tunnel roofs and walls.
6. Electrical wires to be laid inside the tunnel should be laid carefully.
The lighting used during tunnel construction and operation are mainly of the following
Types:-
1. Lantern
2. Coal gas lighting
3. Acetylene gas lighting
4. Electric lightingRAILWAY BRIDGES
Code No.: 2301 Time: 2:30 Hours]
RAILWAY BRIDGES & TUNNELS Maximum Marks: 50
NOTES: Attempt all questions,
Students are advised to specially check the Numerical Data of the question paper in both versions. If there is any difference in the Hindi Translation of any question, the students should answer the question according to the English version.
iii Use of Pager and Mobile Phones by the students is not allowed.
Q1) Answer any two parts.
a) Draw a typical cross-section of a permanent way. Describe its component parts.
b) Define 'Gauge". List the gauges adapted in India. Mention the problems of charge of the page. Explain with a neat sketch the types of rail. 12×5=10 Q2) Answer any three parts.
Differentiate between bridge and culvert. 13-4-12]
Classify the bridge according to dock level. Explain any one of them.
Draw neat sketches of Expansion bearing and knuckle bearing. Define abutment. State the functions of abutment
03) Answer two parts.
Explain with the help of neat sketch the diamond crossing
Why packing of sleeper is done? Describe the procedure of carrying out through packing of sleeper. State lour functions of station. Explain guration station with different arrangements to be provided
Q4) Answer any two parts of the following
Explain with a neat sketch Horse shoe section of turnel.
Lis the methods of tunneling in hard rock. State one advantage of each method
b)
c) Why is the lighting necessary in tunnels?
05) Answer any three parts of following.
Explain drainage method of draining water in tel
13×4-12;
Explain the process of mechanical ventilation with a neat sketch.
Enumerate the precautions to be taken during hedge interface
12 Wrie short note on Grouting and Guniting in case of bridge maintenance
