Question

Assessment 7.0: S&C layouts Produce a report (500 words min) on the operation of S&C layouts, use photographs of operational layouts and identify a range of components used in S&C layouts, for a range of different situations? This assessment must meet the requirements of the following assessment criteria: 91.2.1 'Identify the components utilised in the construction of switch & crossing systems' 91.2.1 'Describe the construction of switch and crossing systems 91.2.1 Describe the materials used in switch and crossing units' 91.2.1 1dentify the types of switch and crossing ayouts' 91.2.1 'Explain the operation of switch and crossing systems 91.2.1 'Explain the geometry required for switch and crossing systems 91.3.3 Describe the potential failure modes of switch and crossing layouts'

alos need minimum 4 failure of S& C

Answer 1

91.2.1 Components utilised in :

a) construction of switch :

- A pair of stock rails

- A pair of tongue rails

- Toe and heel

- gauge tie plates

- A number of slide chairs

- two or more stretcher bars

b) construction of crossing system :

- 2 rails point rail and splice rail are joined

- wing rails and a pair of check rails

- Point rail with Blunt nose

- V rail with 6 mm depth

Construction using the design elements as stated :

Point and Crossings are peculiar arrangement used in permanent way (railway track) to guide the vehicle for directional change. Broadly point and crossing assembly consists of three main components namely Point, Lead and Crossing element. A point consists of one pair of tongue rails and Stock Rails with necessary fittings.Crossing is a device in the form of V-piece introduced in the track to permit movement of wheel flange at the inter section of two running lines.It has gap over which the wheel tread jumps.The track portion between point and crossing is is called lead.

The points and crossing are the vital components of track asset; necessary for diversion of traffic from one track to another track, such diversion may be necessitated for giving precedence to faster trains in the same direction, giving passage to a train moving in the opposite direction or for connecting places not on the direct line of track. Hence the design, laying and maintenance of the points and crossing have a significant influence throughout the section.

Constituents of the points and crossing The switch assembly, the crossing assembly and the lead portion beyond the turnout, turn-in- curve is also important assembly

Type of switch

- Stub switch

- Split switch

Types of crossings :

1. Special class level crossing.

2. Class “A” level crossing.

3. Class “B” level crossing.

4. Class “C” level crossing.

5. Class “D” level crossing.