BCE Railway 4 — Questions and Answers
Question 1: What is the 'heel' of a railroad switch?
- The fixed end of the switch rail farthest from the points (Correct answer)
- The movable tip of the tongue rail
- The center of the frog
- The connection between closure and frog rails
Correct answer: The fixed end of the switch rail farthest from the points
The heel is the fixed end of the switch rail where it joins the closure rail, opposite to the movable point (toe).
Question 2: Which type of railway track structure is used in urban light rail systems embedded in pavement?
- Embedded rail (grooved rail) track (Correct answer)
- Ballasted track
- Slab track with direct fixation
- Open-deck track
Correct answer: Embedded rail (grooved rail) track
Embedded grooved rail is used in street-running light rail systems, where the rail is set flush with the road surface in a slot.
Question 3: The 'Talgo' train design concept primarily achieves passenger comfort through:
- Passive tilting bogies with articulated configuration (Correct answer)
- Active hydraulic tilt systems
- Low center of gravity and wide gauge
- Magnetic levitation technology
Correct answer: Passive tilting bogies with articulated configuration
Talgo trains use passive tilting through pendulum-action bogies and articulated design, reducing the need for high superelevation on curves.
Question 4: What is 'track modulus' in railway geotechnical engineering?
- Stiffness of the track support system per unit length of rail (Correct answer)
- Flexural stiffness of the rail section
- Compressive strength of ballast
- Load-bearing capacity of the subgrade
Correct answer: Stiffness of the track support system per unit length of rail
Track modulus (u) is the distributed foundation stiffness in lb/in/in, representing the support the track receives per unit deflection per unit rail length.
Question 5: What is the primary advantage of 'slab track' over conventional ballasted track?
- Lower maintenance requirements and better long-term geometry stability (Correct answer)
- Lower initial construction cost
- Better vibration absorption
- Easier installation on curves
Correct answer: Lower maintenance requirements and better long-term geometry stability
Slab track (concrete base without ballast) requires significantly less maintenance and retains its geometry longer, though initial costs are higher.
Question 6: In railway signaling, a 'block section' refers to:
- A length of track protected from occupation by more than one train at a time (Correct answer)
- A section of track with maximum speed restriction
- A zone where trains are blocked from entering
- A maintenance exclusion zone
Correct answer: A length of track protected from occupation by more than one train at a time
A block section is a defined length of track in which only one train is permitted at a time, forming the basis of railway safety spacing.
Question 7: Which formula gives the minimum radius of a horizontal curve on a railway track based on speed and superelevation?
- R = V² / (127 × (e + f)) (Correct answer)
- R = V² × e / g
- R = V / (e + f)
- R = V² / (9.81 × e)
Correct answer: R = V² / (127 × (e + f))
The minimum curve radius R = V²/[127(e+f)] relates speed (km/h), superelevation (e), and side friction factor (f) to curve radius in meters.
BCE Railway 4
What is the 'heel' of a railroad switch?