Railway engineering

Points and crossings A crossing or frog is a device

introduced at the point.where two gauge faces cross each other

to permit the flanges of a railway vehicle to pass from one track to another.

A gap is provided from throw to the nose of crossing.

Turn out The combination of lead rails with

curved rails helps in diverting rolling stock from one track to another track.

Rails depending on curvatureLead rails are straightCurved rails have curvature

Turnouts are also provided in yards and sidings.

Constituents of a turnout

Component Parts of a Turnout1. A pair of tongue rails 2. A pair of stock rails 3. Two check rails4. Four lead rails5. A Vee crossing6. Slide chairs7. Stretcher bar8. A pair of heel blocks9. Switch tie plate or gauge10. Parts for operating points- Rods, cranks, levers etc11. Locking system which includes locking box, lock bar, plunger

bar etc.

Crossing

A crossing is a device introduced at the junction where two rails cross each other to permit the wheel flange of a railway vehicle to pass from o.ne track to another.

Crossing

Types of crossings

Based on the angle of crossing:

Acute angle 2 rail gauge faces cross at acute angle.

Obtuse angle 2 gauge faces meet at obtuse angle.

Square crossingTwo tracks cross at right angles.

For manufacturing purposes

Spring crossing Cross over Scissors crossing Diamond crossing Ladder track crossing

Crossings - ComponentsTwo wing rails consisting of a right-hand and a left-

hand wing rail that converge to form a throat and diverge again on either side of the nose.

Wing rails are flared at the ends to facilitate the entry and exit of the flanged wheel in the gap.

A pair of check rails are used to guide the wheels.