LEC Brake Systems & Safety 3

Question 1

What does a 'penalty brake application' automatically enforce on a locomotive?

Accepted Answer

A full emergency brake application that cannot be overridden by the engineer

Answer

A penalty brake application triggers a full emergency brake application that the engineer cannot override, used by safety systems like PTC and alerters.

Question 2

What is the purpose of retainer valves on freight cars, and when would a locomotive engineer request their use?

Accepted Answer

To hold some brake cylinder pressure during brake releases on descending grades

Answer

Retainer valves hold a portion of brake cylinder pressure during the release cycle, helping control train speed on long descending grades.

Question 3

Which type of brake shoe provides a higher friction coefficient at low speeds but tends to overheat on long downgrades?

Accepted Answer

Cast iron shoes

Answer

Cast iron brake shoes provide excellent friction at low speeds but are prone to overheating on sustained downgrades, which can cause wheel damage.

Question 4

What is 'brake shoe squeeze-out,' and what does it indicate?

Accepted Answer

Uneven brake shoe contact causing the shoe to slide partially off the wheel tread

Answer

Brake shoe squeeze-out occurs when misaligned or worn brake rigging causes the shoe to partially leave the wheel tread, indicating a rigging defect requiring inspection.

Question 5

A locomotive engineer notices the brake pipe pressure gauge drops steadily at 8 psi per minute with brakes released. What is the correct action?

Accepted Answer

Report the defect and remove the locomotive from service

Answer

FRA regulations require that brake pipe leakage not exceed 5 psi per minute; a rate of 8 psi per minute indicates a defect requiring the locomotive to be removed from service.

(LEC) Locomotive Engineer Certification Practice Test

(LEC) Locomotive Engineer Certification Practice Test

LEC Brake Systems & Safety 3