LEC Mechanical and Electrical Systems 3

Question 1

What is the function of the 'alerter' (or vigilance device) on a locomotive?

Accepted Answer

Ensure the engineer is alert by requiring periodic acknowledgment

Answer

The alerter requires the engineer to periodically press a button or move a control to confirm alertness; failure to respond triggers a penalty brake application.

Question 2

In a diesel-electric locomotive, what causes 'wheel slip' and how is it initially detected?

Accepted Answer

Traction motors drawing unequal current detected by wheelslip relays or sensors

Answer

Wheel slip occurs when traction motor torque overcomes rail adhesion; it is detected by current imbalance between motors or by axle speed sensors.

Question 3

What is the role of the 'main reservoir' in a locomotive's air system?

Accepted Answer

Provide the primary compressed air supply for all pneumatic systems

Answer

The main reservoir stores compressed air from the compressor and supplies all locomotive pneumatic systems including brakes, controls, and auxiliaries.

Question 4

When a locomotive's cooling water temperature exceeds safe limits, what protective action typically occurs?

Accepted Answer

The engine automatically reduces power or shuts down to prevent damage

Answer

High coolant temperature triggers a power reduction or engine shutdown to protect the diesel engine from thermal damage.

Question 5

What does 'motoring' mean in locomotive operation terminology?

Accepted Answer

Using traction motors to propel the locomotive forward

Answer

Motoring describes the mode where traction motors receive electrical power and convert it to mechanical energy to move the locomotive.

(LEC) Locomotive Engineer Certification Practice Test

(LEC) Locomotive Engineer Certification Practice Test

LEC Mechanical and Electrical Systems 3