Diagnose, adjust, repair, or overhaul railroad rolling stock, mine cars, or mass transit rail cars.

Diagnose, adjust, repair, or overhaul mobile mechanical, hydraulic, and pneumatic equipment, such as cranes, bulldozers, graders, and conveyors, used in construction, logging, and surface mining.

Diagnose, adjust, repair, or overhaul farm machinery and vehicles, such as tractors, harvesters, dairy equipment, and irrigation systems.

Diagnose, adjust, repair, or overhaul buses and trucks, or maintain and repair any type of diesel engines. Includes mechanics working primarily with automobile or marine diesel engines.

Repair only one system or component on a vehicle, such as brakes, suspension, or radiator.

Repair automobiles, trucks, buses, and other vehicles. They master mechanics repair virtually any part on the vehicle or specialize in the transmission system.

Diagnose, adjust, repair, or overhaul aircraft engines and assemblies, such as hydraulic and pneumatic systems. Includes helicopter and aircraft engine specialists.

Repair, adjust, or install audio or television receivers, stereo systems, camcorders, video systems, or other electronic home entertainment equipment.

Install, diagnose, or repair communications, sound, security, or navigation equipment in motor vehicles.

Inspect, test, repair, or maintain electrical equipment in generating stations, substations, and in service relays.