Suspension & Steering 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 Suspension & Steering flashcards as text
What is 'gage widening' and how does a locomotive's suspension respond to it?
Answer: Track spreading beyond nominal gauge — wheelsets can shift laterally, stressing flange and suspension limits
Gage widening occurs when rail spikes or fasteners fail and the rails spread apart, allowing wheelsets to shift outward and potentially climb the outer rail.
A yaw damper is fitted between the truck and the carbody on some high-speed locomotives. What motion does it resist?
Answer: Rotational (yawing) oscillation of the truck relative to the carbody
Yaw dampers resist the rotational hunting and yawing of the truck about the vertical axis, improving high-speed stability.
Which condition is described as a 'rough ride with a periodic shock approximately once per wheel revolution'?
Answer: Flat spot (wheel flat) impacting the rail once per revolution
A flat spot on a wheel creates a single impact each time the flat portion contacts the rail, producing a regular periodic shock tied to wheel rotation speed.
What is the function of traction rods (or traction links) in a locomotive truck?
Answer: To transfer tractive and braking forces from the truck frame to the locomotive underframe
Traction rods transmit the longitudinal forces of traction and braking between the truck frame and the main locomotive underframe while isolating vibration.
Under FRA regulations, what action must be taken if a locomotive is found with a broken main suspension spring in a revenue service inspection?
Answer: Remove the locomotive from service until the spring is repaired or replaced
FRA 49 CFR Part 229 requires that locomotives with broken suspension springs be removed from service because they pose a derailment and handling risk.
What is the relationship between wheel diameter mismatch on the same axle and steering behavior?
Answer: The larger-diameter wheel rolls faster per revolution, causing the axle to steer toward the smaller wheel side
Since both wheels on a solid axle rotate at the same angular speed, the larger wheel covers more linear distance per revolution, causing the axle to curve toward the smaller-wheel side.
Which parameter is most critical when setting suspension spring height during locomotive maintenance?
Answer: Spring free height and compressed (loaded) ride height to ensure proper suspension travel
Correct spring free height and loaded ride height ensure the suspension operates within its designed travel range, preventing coil bind or excessive sag.