unit 1. introduction to railway engineering

RAILWAY ENGINEERING

By: Lohit HavalagiAssistant professor, NKOCET Solapur

BALLAST CESS

BALLAST CRIB

Ballast Crib & Ballast cess

BALLAST CRIB

BALLAST CESS

SLEEPER

RAIL

Points & Crossings

Fishplate & Fish Bolt

Level Crossing

Concrete sleeper

Cast Iron Sleeper

CONONG OF WHEELS

Coning of Wheels

Tractive Resistances

1. Train Resistance I. Speed Independent (Rolling) ResistancesII. Speed Dependent ResistancesIII. Atmospheric Resistances

2. Resistance due to Track ProfileI. Grade ResistanceII. Curve resistance

3. Resistance due to Starting & accelerating4. Wind Resistance

Track stresses

Track stresses

Track Modulus

• Load Per Unit Length of the rail Required to Produce Unit Depression.

• Depends Upon:1. Gauge2. Type of Rail section3. Type of sleeper and density4. Type of ballast section 5. Subgrade

Track stresses

1. Wheel loads2. Dynamic effect of wheel loads3. Hammer Blow4. Lateral Thrust due to Nosing Action5. Pressure Exerted by the flanges of the wheels

on sides of rails6. Stresses due to Irregularity of track7. Additional stresses on curves

Hauling Capacity (H.C) &Tractive Effort (Te)

• Load handled by the locomotive• H.C is the Product of Coefficient of friction &

Weight on the driving wheels.Average value of Coefficient of friction= (1/6)

Buckling of Track Due to Temperature stresses

Stresses in Rail

• Longitudinal Stresses due to Tractive Effort & Braking Forces.

• Thermal stresses• Due irregularity there will be heavy impact on

the rails.• Minimum Ultimate Tensile Strength of Rail =

72.42 kg/cm2

Stresses in the Sleepers

• Stresses in sleepers depends upon:• Wheel load• Irregularities in the track• Speed• Dynamic effect of wheels on rails• Elasticity of the rail

• Efficiency of Fastenings• Design & Dimension of Sleeper• Strength of Sleeper• Track Modulus• Stiffness of the rail• Maintenance of track

Stresses in the Ballast

Stresses in Ballast depends on:• Elastic Property of the sleeper• Degree of compaction• Nature of Ballast bed• Bigger the cess & size of sleeper, lesser the

Pressure in ballast & formation.

Stresses in the Formation

• Stresses in subgrade is decreased by increasing both depth & Size of the Ballast.

• Quality & Gradation of Ballast influences ultimate pressure on formation.