LEC Fuel Systems & Injection 4

Question 1

What is the minimum cetane number typically required for diesel fuel used in locomotive engines?

Accepted Answer

40

Answer

A cetane number of at least 40 is required for reliable ignition in locomotive diesel engines; higher cetane improves cold-start performance and reduces combustion noise.

Question 2

What does water in the fuel system primarily cause in a diesel locomotive?

Accepted Answer

Injector seizure, corrosion, and microbial growth

Answer

Water promotes corrosion of metal fuel system components, can seize closely-toleranced injection parts, and supports microbial growth that clogs filters.

Question 3

Which instrument alerts the engineer to excessively low fuel oil pressure during operation?

Accepted Answer

The fuel oil pressure alarm and indicator light

Answer

The fuel oil pressure alarm activates when pressure drops below the safe operating threshold, warning the engineer of potential fuel starvation.

Question 4

How does biodiesel blending (B20) affect cold-weather operability of locomotive fuel systems?

Accepted Answer

It raises the cloud point, increasing risk of fuel gelling at low temperatures

Answer

Biodiesel has a higher cloud point than petroleum diesel, meaning B20 blends can begin to gel at warmer temperatures, potentially plugging filters in cold weather.

Question 5

What action should an engineer take if the fuel level gauge shows empty but the locomotive is still running?

Accepted Answer

Stop the locomotive safely and report the gauge as potentially faulty or tank as critically low

Answer

An empty fuel gauge requires the engineer to treat the condition as critical — stop safely, report it, and do not risk running dry, which can damage injection components.

(LEC) Locomotive Engineer Certification Practice Test

(LEC) Locomotive Engineer Certification Practice Test

LEC Fuel Systems & Injection 4