LEC Heating, Ventilation & AC 2

Question 1

When operating in extremely cold weather, a locomotive engineer notices the cab heater output has dropped significantly. What is the FIRST action to take?

Accepted Answer

Check for blocked or frozen fuel supply lines to the heater

Answer

Blocked or frozen fuel supply lines are a common cause of reduced heater output in cold weather and should be checked first.

Question 2

What does the term 'recirculation mode' mean in a locomotive HVAC system?

Accepted Answer

Cab air is cycled internally without drawing outside air

Answer

Recirculation mode cycles existing cab air internally, which is useful for rapid temperature changes or when outside air quality is poor.

Question 3

A locomotive engineer detects a strong chemical odor consistent with refrigerant when the AC system is running. What is the correct response?

Accepted Answer

Shut down the AC system and notify maintenance of a suspected refrigerant leak

Answer

A refrigerant odor indicates a leak; the system should be shut down and maintenance notified because refrigerant can be a health hazard.

Question 4

Which regulation governs the required temperature range that must be maintained in a locomotive cab during cold weather operations in the U.S.?

Accepted Answer

FRA 49 CFR Part 229

Answer

FRA 49 CFR Part 229 covers locomotive safety standards, including cab environment requirements such as heating during cold weather.

Question 5

What is the primary purpose of the evaporator in a locomotive air conditioning system?

Accepted Answer

To absorb heat from cab air as refrigerant evaporates through it

Answer

The evaporator absorbs heat from cab air as liquid refrigerant evaporates inside its coils, cooling the air before it is circulated back into the cab.

(LEC) Locomotive Engineer Certification Practice Test

(LEC) Locomotive Engineer Certification Practice Test

LEC Heating, Ventilation & AC 2