Month: January 2019

# Sight Distance And Depending Factors

## Sight Distance

The distance along the centre line of a road at which a driver has visibility of an object, stationary or moving at a specified height above the carriageway is called sight distance.

### The safe sight distance depends upon the following factors

1. Speed of the vehicle.
2. Perception time and break reaction time.
3. The efficiency of the break of the vehicle.
4. The frictional resistance of the road surface.
5. The slope of the road surface.
6. The eyesight of the driver.
7. Weather condition.

Stopping Sight Distance

Passing Sight Distance

# Grade Compensation on Curves of Railway Track

## Grade Compensation on Curves of Railway Track

If a sharp horizontal curve is provided on a railway track with a ruling gradient, the tractive resistance will be increased due to this curve. In order to avoid this resistance beyond the allowable limits, the gradients are reduced on curves, this reduction in gradient at the horizontal curve is called grade compensation on curves.

In Indian Railway, the following are the grade compensation have been recommended.

`Gauge     Grade compensation `

B.G Track – 0.04%
M.G Track – 0.03%
N.G Track – 0.02%

FUNCTIONS OF RAILS

TYPES OF RAILS

Railway Gauge

Functions of Curves For a Railway Track

# Purpose of Providing Gradient in Railway

## Purpose of Providing Gradient in Railway

Gradients are provided to the formation of railway track to achieve the following objects:

1. To provide a uniform rise or fall as far as practicable.
2. To connect the terminal stations situated at different levels.

3. To provide the earthwork of the railway project economical
4. To provide effective drainage of rainwater.

Types of gradient in railway

Types of Rails

# Factor Affecting The Selection Of Gradient For Railway Track

## Factor Affecting The Selection Of Gradient For Railway Track

The factors which govern the selection of a particular gradient in the alignment of a railway track are as follows:
1. Nature of ground
2. The total height to be covered
3. Drainage required.
4. Hauling capacity of railway engines.
5. Safety required.

Gradient in Railway Track

# Types of Fixtures And Fastenings in railway

## Types of Fixtures And Fastenings

The important fittings commonly used in a permanent way(Railway) are as follows:
1. Fish Plates
2. Spikes
A. Dog spikes
B. Screw spikes
C.Round spikes
D. Standard spikes
E. Elastic spikes
3. Bolts
A. Dog or hook bolts
B. Fish bolts
C. Rag bolts
D. Fang nut bolt.
4. Chairs
A. Cast steel chairs
B. Mild steel and Cast iron slide chairs.
5. Blocks
A. Heel blocks
B. Distance blocks
C. Crossings blocks
D. Check blocks.
6. Keys
A. The wooden key for C.I chair
B. M.S key
C. Stuart’s key
D. Morgan key
E. Cotter and tie bars
7. Plates
A. Bearing plates
8. Anchors and anti-creepers.

Creep of Rails

# 6 Functions of Fixture And Fastenings in Railway

## Functions of Fixture And Fastenings

Following are the functions of fixtures and fastenings of railway track:

1. These are used to connect the rails end to end

2. These are used to fix the rails to sleepers and to keep them in a proper position.

3. They allow expansion and contraction of rails due to temperature variation.

4. They provide required tilt of rails.

5. They help to set the points and crossings properly

6. They help to maintain the correct alignment of the track.

Purpose of Welding of Rails

# Advantages And Disadvantages of Broken Brick Ballast

Following are the advantages and disadvantages of broken brick ballast are described below

## Advantages of broken Bricks as Ballast

1. It is cheap.
2. It is locally available.
3. It has fairly good drainage quality.

## Disadvantages of Broken Bricks as Ballast

1. It turns into powder under traffic and makes the track dusty.
2. The rails laid over this ballast get Corrugated.
3. Maintenance of track laid with this ballast becomes difficult.
4. It corrodes metal sleepers and rails.
5. It is unsuitable for heavy and high-speed traffic.