Certification Exam Practice Questions

Locomotive Mechanical Technician Certification Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a locomotive’s air brake system?
• Increase engine power
• Improve fuel efficiency
• Stop and control the train safely
• Lubricate wheel bearings

Rationale: The air brake system is designed to stop and control train

movement safely by using compressed air to apply brake shoes.

• Which component converts electrical energy into mechanical motion

in an electric locomotive?

• Transformer 1 / 4

• Rectifier
• Traction motor
• Governor

Rationale: The traction motor converts electrical energy into

mechanical energy, which drives the wheels.

• What type of engine is most commonly used in modern diesel-electric

locomotives?

• Two-stroke gasoline engine
• Four-stroke diesel engine
• Steam engine
• Wankel rotary engine

Rationale: Most modern locomotives use four-stroke diesel engines

for efficiency, reliability, and torque output.

• What is the function of the governor in a diesel engine?
• Lubricate engine parts
• Reduce emissions
• Regulate engine speed
• Cool the engine

Rationale: The governor controls fuel delivery to maintain consistent

engine speed under varying loads.

• Which of the following is a common cause of wheel slip on

locomotives?

• Low coolant 2 / 4

• Faulty air brakes
• Wet or oily rail conditions
• Improper fuel mixture

Rationale: Wheel slip often occurs when traction is reduced due to

wet, icy, or oily rail surfaces.

• What is the purpose of the dynamic brake on a diesel-electric

locomotive?

• Increase fuel efficiency
• Start the engine
• Slow the train using traction motors as generators
• Charge the battery only

Rationale: Dynamic braking uses traction motors to generate

electricity, which slows the train and dissipates energy as heat.

• Which component in a diesel-electric locomotive stores electrical

energy for auxiliary systems?

• Traction motor
• Battery
• Fuel injector
• Air compressor

Rationale: The battery provides stored electrical energy for auxiliary

systems, lighting, and engine starting.

• What is the primary function of the locomotive’s traction motor

blower? 3 / 4

• Lubricate traction motors
• Cool the traction motors
• Increase engine power
• Charge the battery

Rationale: Traction motor blowers circulate air to prevent

overheating of the motors during operation.

• What is the correct term for the flexible coupling connecting a diesel

engine to a generator?

• Drive shaft
• Flexplate coupling
• Universal joint
• Gearbox

Rationale: The flexplate coupling absorbs engine vibrations while

transmitting torque to the generator.

• Which type of maintenance focuses on inspecting and replacing

components before failure occurs?

• Corrective maintenance
• Preventive maintenance
• Emergency maintenance
• Predictive maintenance

Rationale: Preventive maintenance is scheduled regularly to replace

or service components before they fail.

• / 4