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 operating a long train through an 'S-curve' (reverse curves), what is the main train handling concern?
Answer: Coupler angles change direction, increasing lateral forces that can derail cars
In S-curves, couplers change from one angle to the opposite, and combined with any slack action this can create high lateral forces and potential derailments.
What is the significance of a locomotive's 'continuous tractive effort' rating versus its 'starting tractive effort' rating?
Answer: Starting tractive effort is the force available at low speeds; continuous is the sustained force without overheating traction motors
Starting tractive effort is the high force available at very low speeds, while continuous tractive effort is the lower force sustainable at a given speed without overheating motors.
What train handling adjustment is required when operating with a loaded train on a segment where the grade changes from descending to ascending?
Answer: Increase throttle early so the locomotive is pulling before rear cars reach the sag
Increasing throttle before the sag prevents the locomotive from pulling forward while the rear of the train is still being pushed downhill, which would cause severe run-in.
Under FRA regulations, what is the maximum allowable speed for a freight train with only operative hand brakes and no air brakes?
Answer: 5 mph
FRA regulations restrict movement with inoperative air brakes to not more than 5 mph using only operative hand brakes.
What is the primary advantage of distributing power throughout a long train (distributed power units)?
Answer: It reduces in-train forces by applying traction and braking closer to where it is needed
Distributed power units apply traction and braking forces along the train's length, dramatically reducing peak buff and draft forces on couplers.
When an engineer observes that dynamic brake effort is not responding to handle position changes, what is the correct initial response?
Answer: Apply automatic brakes immediately to compensate for lost braking capacity
Loss of dynamic brake response requires immediate application of automatic brakes to maintain train control, as dynamic braking is no longer a reliable retarding force.
What is 'train line pressure equalization' and why does it matter before a brake test?
Answer: Allowing brake pipe pressure to stabilize after charging so test reductions reflect true brake response
Equalization allows the brake pipe pressure to stabilize at full charge so that a subsequent reduction produces accurate, consistent brake response throughout the train.