Geometric Design of Railway Track CE2303 Railway Engineering

Introduction Parameters determines or affect geometry of the track Gradient Speed Super-elevation etc. Parameter: A numerical or measurable factor forming one of a set that defines a system or sets the conditions of its operation.

Introduction Most of the train derailment due to: Track Defects Vehicular Defect Operational Defect Civil Engineer is mainly concerned with track defects

Introduction Engineer should aware of the track defects and how to remove those defects so that no derailment takes place. Broken Rail

Introduction Railway track should be designed, suiting to load and speed of the train, and meeting the safety and economy requirements.

Introduction A train may derail on the straight track due to the following defects in the track: Defective cross-levels Defective alignment Defective Gauge Low joints

Cross-levels

Rail Joint – unless uniform level

Introduction A train may derail on the curved track due to the following defects in the track: Improper super-elevation Improper radius of curve Improper speed

Gradient

Gradients Provided to negotiate rise or fall

Gradients Represented by distance travelled for a rise or fall

RULLING GRADIENT

Ruling Gradient Steepest gradient in a section Determines maximum load hauled by a locomotive Power of locomotive decided based on ruling All other gradient in the section flatter than ruling

PUSHER OR HELPER GRADIENT

Pusher or Helper Gradient Hilly areas gradient steeper than ruling Extra locomotive required to pull entire load Called as pusher or helper gradient E.g. Budni – Barkhera section (CR)

Momentum GRADIENT

Momentum Gradient Steeper than ruling Falling gradient followed by rising gradient Falling gradient acquires good speed No obstacles in the form of signals

GRADIENT @ Station Yards

Gradient @ SY Prevent standing vehicle rolling from yard due to gravity/strong wind Reduce additional friction require to start locomotive Max. 1 in 400, recommended 1 in 1000 in IR

Grade Compensation

Grade Compensation Curve provide extra resistance Grade reduced at curves BG 0.04% per degree MG 0.03% NG 0.02% per degree

Causes for Rail Accidents in India

Many a times accidents occur on bridges during rainy season. The reason is no regular inspection of bridges and tracks. More over some of the bridges are very old and unable to carry fast speed trains or a even normal train. The Rajdhani and Shatabdi are high sped trains in India which have been designed to travel with the speed of 160 kmph.  But quality of tracks is not good to bear such a high speed in India.