Operating Engineers · Reference & Study Center
Operating Engineers Study Guides
Technical formulas, mechanical principles, interview rubrics, and untimed question reviews for the IUOE Heavy Equipment Operators Aptitude Test.
1. Technical & Interview Guides
7 chaptersOperating Engineers Grade Math, Soil Swell & Hydraulic Physics
8 minGrade slope percentages, cut and fill benchmarks, soil compaction, and hydraulic force
Hydraulic Systems
5 minPascal's Law, cylinders, and how hydraulic elevators work
Levers & Simple Machines
5 minThree classes of levers, force calculations, and real-world examples
Gears & Gear Ratios
7 minTypes, ratios, direction of rotation — and why worm gears matter
Pulleys & Rope Systems
6 minMechanical advantage from pulleys and how elevator roping works
Mechanical Advantage
5 minThe principle behind every gear, pulley, lever, and ramp
IUOE Operating Engineers Apprentice Oral Interview Guide
9 minHeavy equipment operation, preventative maintenance, and union interview strategy
2. Untimed Question & Solution Bank
Browse every question and step-by-step solution in the Operating Engineers bank at your own pace.
Grade & Earthmoving Math
Grade slope percentages, cut/fill elevation, soil swell/compaction, and cubic yardage
Mechanical Principles & Hydraulics
Hydraulic cylinders (F = P × A), leverage, gear reduction, center of gravity, and load charts
Equipment Safety & OSHA Standards
Trenching safety zones, OSHA Subpart CC crane rules, powerline clearances, and hand signals
Oral Interview & STAR Coach
Turn your job stories into 100/100 STAR answers and review the 15 official committee questions.