PTS Railway Hazards and Terminology 3 — Questions and Answers
Question 1: What is a 'rail gap' and why is it considered a serious hazard?
- A space between sleepers that workers can trip in
- A break in the running rail that can cause derailment and is difficult to detect visually (Correct answer)
- The gap between two parallel running rails of the same track
- A gap in the boundary fencing alongside the track
Correct answer: A break in the running rail that can cause derailment and is difficult to detect visually
A rail gap is a break or crack in the running rail that can cause a train to derail, and because it is often hard to spot, it presents a serious threat to both trains and workers.
Question 2: What does 'track gauge' measure on a railway?
- A device used to measure the speed of passing trains
- The distance between the inner faces of the two running rails (Correct answer)
- The thickness of the rail head under traffic load
- The slope of the track on a curve
Correct answer: The distance between the inner faces of the two running rails
Track gauge is the distance measured between the inner faces of the two running rails, with standard gauge being 4 feet 8.5 inches (1,435 mm).
Question 3: Which of the following best describes 'sun kink' as a railway hazard?
- Glare that impairs a driver's vision in direct sunlight
- Lateral buckling of the rail caused by thermal expansion in hot weather (Correct answer)
- Distortion of signal lenses when sunlight hits them
- Overheating of the locomotive engine in summer
Correct answer: Lateral buckling of the rail caused by thermal expansion in hot weather
A sun kink occurs when rails expand due to high temperatures and buckle sideways, creating a potentially severe derailment risk for passing trains.
Question 4: What is the hazard associated with a 'derailed vehicle' near track workers?
- Increased noise levels only
- Risk of secondary derailment, unstable rolling stock movement, and live electrical hazards (Correct answer)
- Reduced visibility due to dust or smoke only
- Contamination of the ballast with fuel oil
Correct answer: Risk of secondary derailment, unstable rolling stock movement, and live electrical hazards
A derailed vehicle presents multiple simultaneous hazards including further uncontrolled movement, potential live electrical contact, and risk of secondary derailments.
Question 5: What is a 'TPWS' system designed to do?
- Track and Position Warning System — alert workers to nearby trains by GPS
- Train Protection and Warning System — automatically brake a train if it passes a red signal (Correct answer)
- Track Panel Warning Signal — indicate unsafe track panels to drivers
- Temporary Possession Work Schedule — plan engineering windows
Correct answer: Train Protection and Warning System — automatically brake a train if it passes a red signal
TPWS (Train Protection and Warning System) automatically applies emergency brakes if a train passes a signal at danger or approaches a hazard at excessive speed.
Question 6: What does 'wrong-line working' mean in railway operations?
- A train operating on a track it does not normally use, requiring special safety precautions (Correct answer)
- A driver misreading a signal and proceeding on the wrong aspect
- A maintenance worker using incorrect tools on a track component
- A train exceeding the posted line speed limit
Correct answer: A train operating on a track it does not normally use, requiring special safety precautions
Wrong-line working occurs when a train operates on a line in the direction opposite to normal or on a track it does not usually use, typically during engineering works.
Question 7: What is meant by the 'line speed' on a particular section of railway?
- The average speed of all trains passing in a given hour
- The maximum permitted speed for trains authorized on that section (Correct answer)
- The speed at which a track inspection car must travel
- The rate at which signals can change from red to green
Correct answer: The maximum permitted speed for trains authorized on that section
Line speed is the maximum speed at which trains are authorized to operate on a given section of track, determined by track condition, geometry, and infrastructure.
PTS Railway Hazards and Terminology 3
What is a 'rail gap' and why is it considered a serious hazard?