Practice Test Geeks(LEC) Locomotive Engineer Certification Practice Test
← All LEC Flashcard Decks

Engine Performance & Diagnostics Flashcards

7 cards from real LEC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Engine Performance & Diagnostics flashcards as text

  1. A diesel locomotive engine experiences a sudden drop in oil pressure while operating at Notch 8. The engineer should FIRST:

    Answer: Immediately place throttle to idle and prepare to shut down

    A sudden oil pressure drop is a critical emergency requiring immediate throttle reduction to idle and engine shutdown preparation to prevent severe engine damage.

  2. What is the purpose of the load regulator on an EMD diesel-electric locomotive?

    Answer: To maintain constant engine RPM by adjusting generator excitation load

    The load regulator controls generator excitation to match electrical load to engine capability, keeping engine RPM constant at each throttle notch.

  3. Which of the following best describes 'dynamic braking capacity' limits related to engine diagnostics?

    Answer: Dynamic braking capacity is limited by traction motor cooling capacity and grid resistor temperature

    Dynamic braking capacity is thermally limited by the ability of grid resistors and traction motors to dissipate the heat generated during braking.

  4. An engine overspeed trip activates during a downhill grade with dynamic brakes applied. What is the most likely cause?

    Answer: The dynamic brake grids have failed open, removing the load from the engine

    If dynamic brake grids fail open, the generator load is removed from the engine, which can accelerate to overspeed if throttle is not immediately reduced.

  5. Water in the fuel system of a diesel locomotive most commonly results in:

    Answer: Injector tip corrosion, rough running, and potential injector failure

    Water in diesel fuel causes injector corrosion, poor atomization, rough combustion, and can lead to catastrophic injector failure.

  6. A locomotive's engine will not transition from idle to Notch 1 when the throttle is advanced. Which system should be checked first?

    Answer: Engine throttle control circuit, governor, and throttle response wiring

    Failure to respond to throttle advancement points to the control circuit, governor, or wiring between the throttle handle and engine speed control system.

  7. Crankcase pressure that exceeds normal limits on a diesel locomotive indicates:

    Answer: Excessive combustion gas blowby past worn piston rings

    Excessive crankcase pressure is caused by combustion gases blowing past worn piston rings into the crankcase, a condition called blowby.