TWS point

 In TWS Point,Distance between tongue rail and stock rail at JOH is 60 m.This distance is 25 mm in IRS Point.When train moves on Point,it does some lateral movement.Due to this larger gap at JOH in TWS Point,wear and tear in wheel and tongue rail is very less compare to IRS Point.

TWS fitting are made for high speed (160 kmph).Stroke of TWS Point machine is 220m.

In IRS Point only closed switch is locked and Open switch is kept free but in TWS both switches are locked.Open switch is locked with Fish tail or clamp.

TWS is not suitable if curve is more than 2 degrees. 

In TWS Point, throw is 220 mm

220 mm = 160 (opening) + 60 (gap at JOH) 

Operating Data as per IRS :S 24/2002 - Amandement No 1

Motor DC series split field.

Throw of point machine -220 mm +4/-1

Time of operation (Max) -5.0 sec

Current Consumption- <_ 5.5 Amp

Rated Voltage- 110 V DC

Max Throw -550 Kg

Slipping load - <_ 700 kg

Stalling load (min) - 1000 kg

Threaded portion of Lock Rod is made of steel .

SSD( Spring Setting Device)

SSD of approved type shall be provided at JOH ( junction of Rail head).

SSD used in TWS is fitted between 13 th and 14 th sleepers

SSD is insulated from both rails.

SSD installation and maintenance is the responsibility of engineering department.

Opening

Out of 220 m throw, during first 60 mm throw closed switch rail get unlocked and open switch moves towards stock rail.

In next 100 mm throw both switch rail move simultaneously thereby open switch rail get closed and closed switch gets locked and open by 100 mm. 

During final 60 mm throw, closed switch gets locked and open switch rail moves 60 mm further resulting total opening of open switch by 160 mm.

Provides direct locking between tongue rail and stock rail in closed and open position.

No strecher bar is used and both the tongue rails move independently of each other.

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