Railway engineering

transcript

Railway Engineering

Submitted by:

Akshay Kaushal (110134)

Jaspreet Singh (110138)

https://www.youtube.com/watch?v=pvg3e2P2TAo

History of Indian Railway

Railway Engineering

• It is a branch of civil engineering concerned with the design, construction, maintenance, and operation of railways.

• Railway engineering includes elements of civil, mechanical, industrial, and electrical engineering.

• Railway engineers handle the design, construction, and operation of railroads and mass transit systems that use a fixed guideway(such as light rail or even monorails).

• Typical tasks would include determining horizontal and vertical alignment design, station location and design, construction cost estimating, and establishment of signaling & controlling system.

• Railroad engineers can also move into the specialized field of train dispatching which focuses on train movement control.

Section of Permanent Way

RAIL GAUGE

The gauge of a railway track is defined as the clear minimum perpendicular distance between the inner faces of the two rails.

Dimension of gauges

1. Broad Gauge(BG) 1676mm(5’6”)

2. Standard Gauge(SG) 1435mm

3. Metre Gauge(MG) 1000mm

4. Narrow Gauge(NG) 762mm(2’6”)

5. Light Gauge 610mm

Coning of Wheels

• Coning of wheels – The distance between the inside edges ofwheel flanges is generally kept less than the gauge. Gap isabout 38 mm on Either side. Normally the tyre is absolutelyahead centre on the head of the rail, as the wheel is coned tokeep it in this central position automatically. These wheel areconed at a slope

• Theory of coning:- On a level track, as soon as the axle movestowards one rail, the diameter of the wheel tread over the railincreases, while It decreases over the other rail. This preventsto further movement And axle retreats back to its originalposition (with equal dia or both rails and equal pressure onboth rails).

Coning of Wheel on Level-track

The high carbon rolled steel sections, which are laidend-to-end, in two parallel lines over sleepers toprovide continuous and leveled surface for the trainsto move and for carrying axle loads of the rollingstock are called rails.

Functions of the rails:

To provide continuous and level surface for the movement of trains with minimum friction with steel wheels of the rolling stock;

Provide strength, durability and lateral guidance to the track;

Transmit the axle loads to sleepers which transfer the same load to the underlying ballast and formation;

Bear the stresses developed due to heavy vertical loads, breaking forces and temperature variance.

RAILSTypes of rails:

1. Double Headed Rails (DH Rails)

2. Bull Headed Rails (BH Rails)

3. Flat-footed Rails (FF Rails)

Length of Rails

On Indian Railways the standard lengths are the following:

Length = 12.80 m. (42 ft.) for BG (say 13 m) andLength = 11.89 m. (39 ft.) for MG (say 12 m)

Corrugated or Roaring Rails

In certain places, head of rails are found to becorrugated rather than smooth and straight,when the vehicles pass over such rails, a roaringsound is created which is intense enough to beunpleasant.

Hogged RailsDue to battering action of wheels over the end of the rails, therails get bent down and get deflected at the ends. These rails arecalled hogged rails.

Measures taken to rectify the hogged rails are:

1. Cropping

2. Replacing

3. Welding

4. Dehogging

Reason of Hogging!

https://www.youtube.com/watch?v=9njqDgjIcWQ

Kinks In RailsWhen the ends of adjoining rails move slightly out of position, “shoulders” or “kinks” are formed.

Measures taken to rectify kinks in rails:

1. By correcting alignment at joints and at curved locations.

2. Proper packing of joints.

3. Proper maintenance of the track periodically in repect of cross levels, gauge, alignment, welding of worn out portions etc.

Buckling of RailsBuckling means the track has gone out of its original position or alignment due to prevention of expansion of rails in hot weather on account of temperature variations.

Damaged Rails

These are the rails which should be removed on account of their becoming unsafe for a railway track.

Rail Features

• Crushed Heads

• Square or Angular Break

• Split Heads

• Split Web

• Horizontal Fissures

• Transverse Fissures

• Flowing Metal in Heads

• Horizontal Cracks

Crushed Head

Split Heads

Horizontal and Transverse Fissures

Flowing Metal in Heads

Rail Joints

• Supported Rail Joint• Suspended Rail Joint• Bridge Joint• Base Joint• Welded Rail Joint• Staggered or Broken Joint• Square or Even Joint• Compromise Joint• Insulated Joint• Expansion Joint`

Rail Joint

Insulated Joint

Expansion Joint

Creep of RailsCreep is defined as the longitudinal movement of the rail with respect to the sleepers.

Defects of Creep

(i) Sleepers move out of position thereby the rail gauge.

(ii) Position of points and crossings are disturbed.

(iii) Interlocking mechanism getsdisturbed.

Remedies or Prevention of Creep

• Pulling back of rails

• Provision of Anchors or Anticreepers.

• Use of steel sleepers.

Anticreeper

Sleepers

Sleepers are the transverse ties that are laid to support the rails. They transmit wheel load from the rails to the ballast.

Classification of sleepers

(i) Wooden sleeper

(ii) Metal sleeperCast iron sleeper

Steel sleeper

(iii) Concrete sleeperReinforced concreteSleeper (R.C.C)

Prestressed ConcreteSleeper .

Wooden Sleepers

• Hard wood such as, sal and teak

• Soft wood such as, chir and deodar

Metal Sleepers

Concrete Sleepers

Sleeper Density

Sleeper density is the number of sleepers Perrail length. It is specified as (M+x) or (N+x),where M or N is the length of the rail in metersand x is a number that varies according tofactors such as axle load, speed, type & sectionof the rail etc.

It varies in India from M+4 to M+7 for maintracks.

Track Fittings & Fastenings• Fish plates

• Spikes

– Dog spikes

– Screw spikes

– Round spikes

– Standard spikes

– Elastic spikes

• Bolts– Dog or Hook bolt– Fish bolt– Rag bolt– Fang nut and bolt

• Keys– Wooden key for C.I. Chair– M.S. key and steel trough

sleepers– Stuart’s key– Morgan key– Cotter and tie bars

• Chairs

– Cast steel chairs

– Mild steel and Cast Iron Slide Chairs

• Blocks

– Heel blocks

– Distance blocks

– Crossing blocks

– Check blocks

• Plates

– Bearing Plates

– Saddle Plates

Track Fittings & Fastenings contd..

Fish Plate

Dog Spike

Screw spikes

Bearing Plate

Ballast

To provide structural support for the track, holding it in good line and surface

To distribute the load evenly to the subballast and subgrade and thus help to provide stability

Provide for drainage

Ballast in railroad terminology is durable granular material placed between

the crosstie and the sub ballast to hold the track in line and grade.

The primary purposes of ballast are:

BALLAST

SUBBALLAST SUBGRADE

BALLAST SECTION

Types of Ballast

• Broken Stone• Gravel or River Pebbles or Shingle• Ashes or Cinders• Sand• Mooram• Kankar• Brick Ballast• Blast Furnace Slag• Selected Earth

Ballast Size

• For wooden sleepers = 5.1 cm

• For steel sleepers = 3.8 cm

• For under switches & crossings = 2.54 cm

Points & Crossings

• Points and crossings provide flexibility ofmovement by connecting one line to anotheraccording to requirements.

• They also help for imposing restrictions overturnouts which necessarily retard themovements.

• From safety aspect, it is also important as pointsand crossings are weak kinks or points in thetrack and vehicles are susceptible to derailmentsat these places.

Turnouts• It’s the simplest combination of points and crossings which

enables one track either a branch line or a siding, to take off from another track.

• Parts of a turnout:– A pair of points or switches– A pair of stockrails– A Vee crossing– Two check rails– Four lead rails– Switch tie plate– Studs or stops– Bearing plates, slide chairs, stretcher bars etc.– For operating the points – rods, cranks, levers etc.– For locking system – locking box, lock bar, plunger bar etc.

Types of Switches

CrossingsA crossing or a frog is a device which provides two flangewaysthrough which the wheels of the flanges may move, when tworails intersect each other at an angle.

Acute Angle Crossing

Diamond Crossing

Square Crossing

Track Junctions• Turnouts• Symmetrical split• Three throw switch• Double turnout or Tandem• Diamond crossing• Cross overs• Single slip and double slip• Gauntlet track and ladder tracks• Temporary diversion• Triangle• Double junctions

Turnout

Symmetrical split

https://www.youtube.com/watch?v=L_wOPY5Pu-A

How Railway Track Changes

Signalling It consists of the systems, devices and means by which trains are operated efficiently and tracks are used to maximum extent, maintaining the safety of the passengers, the staff and the rolling stock.

On the basis of Operating Characteristics:

• Detonating Signals (Fog or audible signals)

• Hand signals (Visual Indication signals)

• Fixed signals (Visual Indication signals)

Detonating Signal

Hand Signals

Fixed Signals

• Stop or Semaphore type Signals

• Warner Signals

• Shunting Signals (Disc or Ground Signals)

• Coloured-light Signals

On the basis of Functional Characteristics:

Semaphore type signals

Warner Signals

Shunting Signals

Coloured-light Signals

• Reception Signals

– Outer signals

– Home signals

• Departure Signals

– Starter

– Advance Starter

On the basis of Locational Characteristics:

Departure Signals

• Repeater or Co-acting signals

• Routing Signals

• Calling on signals

• Point indicator

• Modified lower quadrant semaphore signal

• Miscellaneous signals

On the basis of Special Characteristics:

High Speed Bullet Train

https://www.youtube.com/watch?v=2-_yS60NhyM

THANK YOU