Railway Flashcards

What is the 'heel' of a railroad switch?

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).

Which type of railway track structure is used in urban light rail systems embedded in pavement?

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.

The 'Talgo' train design concept primarily achieves passenger comfort through:

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.

What is 'track modulus' in railway geotechnical engineering?

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.

What is the primary advantage of 'slab track' over conventional ballasted track?

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.

In railway signaling, a 'block section' refers to:

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.

Which formula gives the minimum radius of a horizontal curve on a railway track based on speed and superelevation?

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.