Train Handling and Performance Flashcards
7 cards from real LEC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Train Handling and Performance flashcards as text
When calculating a train's stopping distance, which variable does NOT directly factor into the calculation?
Answer: Locomotive cab color and visibility markings
Stopping distance is determined by physics—speed, weight, brake force, and grade—not by the visual markings on the locomotive.
What is the correct procedure for a 'set and release' brake test after picking up cars from a yard?
Answer: Make a 6-pound brake pipe reduction, observe brake application, then release and observe release throughout the train
A set-and-release test uses a 6-pound reduction to verify brakes apply and release properly after a pick-up before proceeding.
How does the position of helpers (pushers) affect in-train forces compared to head-end power only?
Answer: Pushers reduce draft forces at the rear but can increase buff forces near the helper cutout point
Pusher locomotives apply force from the rear, reducing coupler tension at the back but creating compression near the point where pusher contribution transitions to head-end pull.
What does 'thermal fade' refer to in the context of train braking?
Answer: Reduction in brake shoe friction effectiveness due to heat buildup from prolonged braking
Thermal fade occurs when brake shoes overheat from sustained braking, reducing the friction coefficient and diminishing braking effectiveness.
When operating with an empty train on a descending grade, how does required brake effort compare to a loaded train on the same grade?
Answer: Empty trains require less brake effort because gravitational force is lower
Lighter empty trains have less gravitational force pulling them downhill, so less retarding force is needed to maintain or reduce speed on a given grade.
What is the engineer's responsibility regarding the 'bad order' of a car discovered to have a defective brake during an initial terminal brake test?
Answer: The defective car must be set out or its brakes manually applied before the train departs
FRA rules require a car with a defective brake discovered during a required brake test to be set out or have its brakes secured before departure.
When transitioning from dynamic braking to air braking at high speed, what technique minimizes coupler shock?
Answer: Overlap the two systems by making a light automatic brake application before fully releasing dynamic brakes
Overlapping a light automatic brake application with the reduction of dynamic braking maintains retarding force continuity and prevents slack run-in during the transition.