This document discusses railway engineering concepts related to points, crossings, and turnouts. It describes that a crossing allows the flanges of a railway vehicle to pass from one track to another where the gauges cross. A turnout uses lead rails and curved rails to divert rolling stock from one track to another. The key components of a turnout are tongue rails, stock rails, check rails, lead rails, a Vee crossing, and parts for operating the points. The document also describes different types of crossings, including acute angle, obtuse angle, and square crossings, as well as components like wing rails and check rails.

1. Railway engineering

2. 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.

3. Turn out
 The combination of lead rails with curved
rails helps in diverting rolling stock from
one track to another track.
 Rails depending on curvature
Lead rails are straight
Curved rails have curvature
 Turnouts are also provided in yards and
sidings.

5. Constituents of a turnout

6. Component Parts of a Turnout
1. A pair of tongue rails
2. A pair of stock rails
3. Two check rails
4. Four lead rails
5. A Vee crossing
6. Slide chairs
7. Stretcher bar
8. A pair of heel blocks
9. Switch tie plate or gauge
10. Parts for operating points- Rods, cranks, levers etc
11. Locking system which includes locking box, lock bar,
plunger bar etc.

7. 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.

8. Crossing

9. 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 crossing
 Two tracks cross at right angles.

10. For manufacturing purposes
 Spring crossing
 Cross over
 Scissors crossing
 Diamond crossing
 Ladder track crossing

12. Crossings - Components
 Two 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.