Showing posts with label transportation engineering. Show all posts
Showing posts with label transportation engineering. Show all posts

Tuesday, 9 January 2018

Coning of Wheels

Coning of wheels is a method of beveling the wheels to avoid depreciation to the wheels and rims. Normally the wheels are conned by a cone of semi-angle. It is based on the theorem of coning. Read on to get more idea.

Introduction

Railway wheels are usually beveled by means of a cone semi-angle of the arrangement of 1/20 (rad.). The rails are also fixed at this identical angle to the perpendicular. The width of the wheel is generally 140 mm and the rail top is approximately 80 mm. The proportions of the region of liaison between an encumbered wheel and rail reckon on the exact shapes of the wheel pace and rail head. It also depends on the extent of the load occupied.

Coning of Wheels

The space between the inner borders of wheel rims is by and large kept less than the measurement of the track. This results in a gap between the wheel rims and running ends of the rails which is approximately equal to 1 cm, (3/8) on both side. More often than not, the tread of wheels is perfectly the dead centre of the beginning of the rail, since the wheel is chamfered to keep it in this middle position involuntarily. Thus the wheels are beveled at an inclination of 1 in 20.

Advantages of coning the wheels

(i) Coning the wheels reduces the depreciation of the wheel rims and rails. Depreciation is caused because of the friction action of rims with inner faces of the rail top.

(ii) Coning also gives an option of lateral drift of the hinge with is wheels.

(iii) Coning also prevents, to some extent, the slipping of the wheels.

Friday, 2 October 2015

Permanent way

 A permanent way is the combination of rails, sleepers, ballasts, fixtures and fastenings, etc.

This term is used to distinguish the finished and permanent track from a temporary track which is laid for temporary work, i.e. for transporting construction material etc on major construction sites.

 such a temporary track is removed as soon as the construction completed. the purpose of use of a permanent way is to provide the permanent facility for safety and quick movement of normal  commercial  traffic between the starting and destination stations. permanent way costs nearly 40% of the total investment to the railways.

Requirements of  Ideal  permanent   way:-

 

1. The alignment of the should be correct.

2. The track should process sufficient elasticity. It should also possess sufficient lateral rigidity and stiffness so that it may withstand the lateral thrust and centrifugal forces.

3. The track should be designed that load of the train should be distribute uniformly over it.

4. The gauge of track should be correct and uniform.

5. The track should possess high resistance to damage at the time of derailment and its maintenance cost is minimum.

6. In straight reaches, the rail level should be same while on curves, proper super elevation should be provided.

7. The friction between the wheels of rolling stock and rail should be minimum.

8.The gradient should be uniform joints, point and crossings should be designed and maintained properly.

9.Facilities of repair, replacement etc of damage portion of track should be adequate.