1. What causes wheel burns?
a) Slipping of wheel on rail surface
b) Falling of metal chunks
c) Manufacturing defects
d) High speed
Explanation: Slipping of wheel of locomotive on rail causes generation of extra heat. This affects the rail surface and a depression on the rail surface is created leading to wheel burns.
2. Which of the following locations are less likely to develop wheel burns?
a) Steep gradients
b) Heavy braking incidences
c) Near water columns
d) On flat gradient
Explanation: Wheel burns are generally found on steep gradients because there is less chance of slipping of wheels on flat gradients. Sometimes, more heat is generated in braking operations and leads to wheel burns.
3. Which of the following defects occur because of heavy bearing pressure on small area of contact?
a) Shelling and Black spots
b) Scabbing of wheels
c) Hogging of wheels
d) Corrugation of wheels
Explanation: Huge internal stresses are produced because of heavy pressure on small area. This causes horizontal separation of metal. This defect is called as Shelling and black spots.
4. When vehicles pass over corrugated rails, a roaring sound is produced.
a) true
b) false
Explanation: Locking of air takes place when vehicles pass over corrugated rails. This produces a sound similar to roaring and is called Roaring of rails.
5. What can be done for removing Corrugation?
a) Grinding the rail head
b) Shovel packing
c) Tilting of rails
d) Scabbing of rails
Explanation: Corrugation causes wear of rails, disrupts the packing and results in rapid oscillation of rails. It can be removed by grinding the rail by fraction of a millimetre.
6. How can rail flaws be detected?
a) By visual examination
b) By rail flaw detection equipment
c) By visual examination or equipment
d) By using chemicals
Explanation: Flaws are the defects which can lead to fracture of rails. Thus their detection is important and can be done visually or with the help of equipment.
7. What is another name of Ultrasonic rail flaw detection technique?
a) Non-destructive method of testing
b) Destructive method of testing
c) Method of visual examination
d) Metallurgical flaw detection
Explanation: The rails/joints are not opened in USFD method. This method is also called Non-destructive method of testing of rails.
8. What is the minimum frequency of ultrasonic waves?
a) 20,000 cycles per second
b) 25,000 cycles per second
c) 31,400 cycles per second
d) 25,000 cycles per minute
Explanation: Ultrasonic waves are the waves having frequency more than 20,000 cycles per second. They follow principles of reflection, refraction and transmission.
9. How defects are identified using ultrasonic waves?
a) They pass through the flaw
b) They reflect back from the flaw
c) They give sound when encountered a flaw
d) They release heat at location of flaw
Explanation: When the ultrasonic waves detect a flaw they have a property of reflecting back. This is used for detection of defects in the rail.
10. Crystal transducers are used for ________
a) Production of ultrasonic frequency
b) Measuring the cracks in rails
c) Shaping the wheels
d) Production of sound
Explanation: Crystal transducers are made of Barium or Quartz and are the simplest method used for production of ultrasonic frequency. This is then used for detection of flaws.