What influence does increased wheel rail conicity have on a railway vehicle?
A worn wheel better matches a rail and therefore has a smoother RRD function. However, high conicity of a worn wheel reduces the critical speed of a wheelset and results in severe vehicle oscillations (hunting).
What are the causes of rail failure?
Most common cause of rail failure is the fatigue fracture which is due to imperfections present in the material or due to crack formation during service. Thus successful performance of rails is based on their resistance to crack initiation and crack propagation.
What are the forces acting on railway track?
Forces Acting on the Track
(a) Vertical loads consisting of dead loads, dynamic augment of loads including the effect of speed, the hammer blow effect, the inertia of reciprocating masses, etc. (b) Lateral forces due to the movement of live loads, eccentric vertical loading, shunting of locomotives, etc.
What causes train tracks to buckle?
Buckles are typically caused by a combination of three major factors: high compressive forces, weakened track conditions, and vehicle loads (train dynamics).
What is conicity in rail wheel?
Conicity is a characteristic that describes the tire’s tendency to roll like a cone. In simple terms, the train wheels are not like our traditional wheels used in any other vehicle but are conical. Conicity is used to investigate the dynamic interactions between railway vehicles and tracks.
Which type of profile is suitable for a railway track?
Flat bottomed rail is the dominant rail profile in worldwide use.
What are the different types of rail failures?
Defects in rails; shatter cracks; detailed fracture; shelling; head-checks; dark-spots; wear. Resistance to structural failure as well as excessive wear is the major criterion involved in the assessment of the structural integrity of rails.
What are the factors that cause heavy damage to the railways?
Through low hills, gaps or tunnels, the railway tracts are laid down. Due to high relief, scattered population and lack of economic opportunities, it poses a problem to construct railways in the Himalayan Mountainous region. These factors cause heavy damage to the railways.
What are the various types of stresses induced in railway track?
Tensile stresses are induced in winter due to contraction and compressive stresses are developed in summer due to compression.
Which of the following is NOT type of force acting on the track?
Which of the following is not a type of force acting on the track? Explanation: The movement of locomotive on the track introduces various types of forces in it. These forces include Vertical loads, Lateral and longitudinal forces, Contact stresses, etc. There is absence of Magnetic field and thus no magnetic force.
Why is it possible for railway tracks to buckle even though there are gaps?
Europe and the United States are experiencing record-breaking temperatures this summer. Intense heat causes steel railroad tracks to expand and to buckle under the extra stress. Trains reduce their speed in extreme heat to put less additional force on the tracks, resulting in delays.
At what temperature do rails buckle?
Because rails are made from steel, they expand as they get hotter, and can start to curve this is known as ‘buckling’. Most of the network can operate when track temperatures heat up to 46°C – roughly equivalent to air temperature of around 30°C – but rails have been recorded at temperatures as high as 51°C.
What is a wheel profile?
The “wheel profile” refers to the thickness of the wheel, so, wheel profile measurement is the measurement of the thickness of the wheel. Over time the wear and tear on railway wheels can affect the quality of them and have an impact on the interaction between the wheels and the rails.
Which of the rails are mostly used in railway track?
About 90% of the railway track in the world is laid with this form of rails. In India, flat-footed rails are most commonly used.
What are the 4 main parts of a railway?
Typical Railway Track Components Overview – Sleepers, Fishplates, Fasteners and Spikes. Railroad track is known a stable structure that mainly consists of rail sleepers, fishplates and fasteners. It ensures the transportation of trains through providing a dependable surface for their wheels.
What do you mean by failure of rails?
A rail is said to have failed if it is considered necessary to remove it immediately from the track on account of the defects noticed on it. The majority of rail failures originate from the fatigue cracks caused due to alternating stresses created in the rail section on account of the passage of loads.
What is the name of the defect in rail due to abnormality of heavy load?
Shelling is the progressive horizontal separation of metal that occurs on the gauge side, generally at the upper gauge corner. It is primarily caused by heavy bearing pressure on a small area of contact, which produces heavy internal shear stresses.
What are the problems that rail transport suffers from?
Rail transport suffers from certain problems. Many passengers travel without tickets. Thefts and damaging of railway property has not yet stopped completely. People stop the trains, pull the chain unnecessarily and this causes heavy damage to the railway.
What are the problems faced by railway transportation?
What are the problems faced by the Indian railway?
- A. Ticketless travelling.
- B. Damage and theft of railway property.
- C. Unnecessary use of emergency chain.
- D. Rough terrain.
What is creep in railway?
Creep of Rail is defined as a longitudional movement of rail with respect to sleeper. Rail have the tendency to gradually move in the direction of dominant traffic. The creep of rail is common to all railway tracks and its value varies from almost nothing in some cases to about 130 mm/ month in creep.
Why do rail tracks expand?
Intense heat causes steel railroad tracks to expand and to buckle under the extra stress. Trains reduce their speed in extreme heat to put less additional force on the tracks, resulting in delays.
What are the 7 types of forces?
Or to read about an individual force, click on its name from the list below.
- Applied Force.
- Gravitational Force.
- Normal Force.
- Frictional Force.
- Air Resistance Force.
- Tension Force.
- Spring Force.
What are the 5 main types of forces?
Some examples of force are:
- Gravitational force.
- Electric force.
- Magnetic force.
- Nuclear force.
- Frictional force.
Why gaps should be left between two successive rails?
The gaps left between successive rails on a railway track, the reason is that the rails expand in summer. The gap is provided to allow for this expansion. If no gap is left, the expansion in summer will cause the rails to bend sideways. That will result in train accidents.
Why do rails not buckle in hot countries?
Why don’t rails get hot in Europe? The truth is they do. However, in countries typically hotter than ours, rails are stressed to withstand higher temperatures. Hot weather can cause a great deal of disruption to the railway so Britain’s rails are pre-stressed to help them resist high temperatures.