LEC Train Handling and Performance 2

Question 1

When descending a steep grade, what is the primary purpose of making a minimum reduction before the grade?

Accepted Answer

To test brake responsiveness before heavier braking is needed

Answer

A minimum reduction before a descending grade tests brake function and establishes control before additional braking force is required.

Question 2

What effect does increasing train speed have on braking distance on level track?

Accepted Answer

Braking distance increases with the square of speed

Answer

Braking distance increases with the square of speed because kinetic energy—which must be dissipated—is proportional to velocity squared.

Question 3

During cold weather operations, what is the main concern with slack in a long train during initial movement?

Accepted Answer

Rapid slack run-in can cause buff forces that derail cars

Answer

In cold weather, frozen or stiff wheel bearings and brakes can cause sudden slack run-in when cars start moving, generating dangerous buff forces.

Question 4

What is the correct action when a locomotive's wheel slides during dynamic braking?

Accepted Answer

Reduce dynamic brake effort to allow wheels to recover traction

Answer

Reducing dynamic brake effort decreases the retarding force, allowing slipping wheels to recover traction before increasing braking again.

Question 5

Which train handling technique best prevents run-in when transitioning from upgrade to level track?

Accepted Answer

Reducing throttle gradually as lead units approach the crest

Answer

Gradually reducing throttle as lead units approach the crest prevents the train from bunching when rear cars are still being pushed uphill.

(LEC) Locomotive Engineer Certification Practice Test