Modernization of Track for High Speeds

Modernization Transport more passengers/goods at high speed, safe, economic

Modernization Speed > 120 Kmph is considered as High Speed

Modernization In order to achieve this speed – track modernization is needed

Strength Requirements Rail Heavier sections of rail to provide adequate wearing strength

Strength Requirements Rail Heavier sections – 60 kg/m or 52 kg/m Presently – kg/m to kg/m

Strength Requirements Rail Joints Normal joint NOT suitable for High Speed Severe blow due to joints

Strength Requirements Rail Joints LONG WELDED RAILS (LWR) CONTINUOUS WELDED RAILS (CWR)

Strength Requirements Rail Joints No temperature stress Length – 200 m to 1 km – Indian Conditions

Strength Requirements Curve Radius Curve Radius 500 – 600 m

Strength Requirements Sleepers Concrete sleepers highly suitable for HS

Strength Requirements Sleepers High ‘Sleeper density’ recommended 1660 numbers/km (160 Kmph) 1540 numbers/km (130 Kmph)

Strength Requirements Ballast Better quality ballast Depth of cushion – 150 mm to 300 mm

Strength Requirements Bridges & Culverts Strengthening existing bridges & culverts Thickness of web/flanges to be increased to bear additional BM & Shear

Strength Requirements Track Drainage Should be free from silt

Strength Requirements Level Crossings Should be replaced with vehicle underpass

LEVEL CROSSINGS

Level Crossings Railway line & road surface meet at same level Surface of road kept at rail level

Level Crossings Guard rails are provided & spiked to wooden sleepers

Classification Procedure Classification of Level-crossing is based on the density of road and railway traffic

Classification Procedure Census of traffic passing through the level crossing is made for continuous period of 7 days

Classification Procedure Census of number of trains passing through the level crossing is also counted for same period

Classification Procedure Weighted figure of road traffic calculated: Bullock cart, car, tonga, truck – 1 unit

Classification Procedure Weighted figure of road traffic calculated: Cycle Rickshaw– 1.5 unit

Classification Procedure Weighted figure of road traffic calculated: Bicycle– 0.25 unit

Classification Procedure Average weighted figure of road traffic for 24 hours is then worked out

Classification Procedure Multiplication of average weighted vehicles & no. of trains leads to classification

ClassValue A>12000 B>3000 C>1000 D<1000

TUNNELLING

Full Face Method Adopted only for small tunnels, dimension do not exceed 3 m

Full Face Method

Vertical columns are fixed at the face of the tunnel

Full Face Method A series of drill holes mm dia about 1200 mm centre to centre drilled

Full Face Method Holes are charged with explosives

Full Face Method Mucking tracks could be laid once for all on the tunnel floor and extended as the work progress

Heading & Bench Method Method adopted for railway tunnels

Heading & Bench Method Heading is the top portion which will be 3700 m to 4600 m ahead of bottom portion, called as bench

Heading & Bench Method Heading & Bench portion simultaneously bored and bench is used for removal of muck

Heading & Bench Method Advantage: drilling of holes for explosives and removal of muck do not interfere each other

Heading & Bench Method

Drift System Drift is first driven size of 3000 mm by 3000 mm All horizontal openings made in a tunnel is known as drift

Drift System Drill holes are provided all around the drift hole for the entire cross section-filled with explosives All horizontal openings made in a tunnel is known as drift

Drift System Drift may at centre or at sides All horizontal openings made in a tunnel is known as drift

Pilot Tunnel Method There are two tunnels: Main Tunnel Pilot Tunnel

Pilot Tunnel Method Pilot tunnel is first driven for full length

Pilot Tunnel Method Pilot tunnel is connected with main tunnel as many points as needed

Pilot Tunnel Method Main tunnel can be started drilling

Pilot Tunnel Method Pilot tunnel is useful for removal of muck, provide lighting, ventilation

Pilot Tunnel Method Also tunnel can be started from number of points