LEC Suspension & Steering 3

Question 1

What is the role of the center plate (center bowl) in a locomotive truck assembly?

Accepted Answer

It is the pivot point that allows the truck to rotate under the locomotive body

Answer

The center plate acts as the pivot bearing between the locomotive underframe and the truck, allowing the truck to swivel as the locomotive negotiates curves.

Question 2

Lateral side bearers on a locomotive truck are set with a specific clearance. What happens if this clearance is excessive?

Accepted Answer

Excessive body roll and instability at speed

Answer

Excessive side bearer clearance allows too much body roll, reducing ride quality and potentially causing unsafe lateral dynamics at higher speeds.

Question 3

A locomotive engineer reports a 'stiff ride' with harsh impacts over track joints. Which suspension component is most likely at fault?

Accepted Answer

Failed or hardened suspension springs or dampers

Answer

Failed or hardened springs and dampers lose their ability to absorb track irregularities, transmitting impacts directly to the locomotive body as a harsh ride.

Question 4

What is 'truck warp' (or truck lozenging) and why is it a concern?

Accepted Answer

Diagonal distortion of the truck frame causing unequal wheel loading

Answer

Truck warp is a diagonal racking of the truck frame that causes two diagonally opposite wheels to be lighter on the rail, risking derailment.

Question 5

Which measurement is used to assess wheel tread conicity on a locomotive wheelset?

Accepted Answer

Tread angle and wear profile geometry

Answer

Tread conicity is defined by the profile angle and wear shape of the tread, which determines how well the wheelset self-centers and resists hunting.

(LEC) Locomotive Engineer Certification Practice Test

(LEC) Locomotive Engineer Certification Practice Test

LEC Suspension & Steering 3