Overhead cranes—often called bridge cranes—are the quiet workhorses that keep heavy industry moving. This long-form walkthrough shows how a full overhead crane system comes to life inside a structural building. You’ll see rails and runway alignment—with the same checklists pro installers use.
What an Overhead/Bridge Crane Is
An overhead crane rides on parallel runways anchored to a building frame, with a trolley that travels left-right along the bridge and a hoist that lifts the load. The system delivers three axes of motion: cross-travel along the bridge.
You’ll find them in fabrication bays, steel plants, power stations, oil & gas shops, precast yards, and logistics hubs.
Why they matter:
Safe handling of very heavy, unwieldy loads.
Huge efficiency gains.
Lower risk during rigging, lifting, and transport inside facilities.
High throughput with fewer ground obstructions.
What This Install Includes
Runways & rails: continuous beams and rail caps.
End trucks: wheel assemblies that ride the rail.
Bridge girder(s): single- or double-girder configuration.
Trolley & hoist: reeving, hook block, upper limit switches.
Electrics & controls: VFDs, radio remote, pendant.
Stops, bumpers & safety: end stops, buffers, travel limits.
Based on design loads and bay geometry, you may be dealing with modest shop lifts or major industrial picks. The installation flow stays similar, but the scale, lift plans, and checks grow with the tonnage.
Make-Ready & Surveys
A clean install is mostly planning. Key steps:
Drawings & submittals: Freeze the GA and verify reactions with the structural team.
Permits/JSAs: Job Safety Analysis (JSA) for each lift step.
Runway verification: Survey columns and runway beams for straightness, elevation, and span.
Power readiness: Lockout/tagout plan for energization.
Staging & laydown: Mark crane components with ID tags.
People & roles: Brief everyone on radio calls and stop-work authority.
Tiny survey errors balloon into hours of rework. Measure twice, lift once.
Alignment That Saves Your Wheels
Runway alignment is the foundation. Targets and checks:
Straightness & elevation: Laser or total station to set rail height.
Gauge (span) & squareness: Use feeler gauges on splice bars, torque rail clips.
End stops & buffers: Verify clearances for bumpers at both ends.
Conductor system: Mount conductor bars or festoon track parallel to the rail.
Record as-built readings. Correct now or pay later in wheel wear and motor overloads.
Girder Erection & End Trucks
Rigging plan: Choose spreader bars to keep slings clear of electricals. Taglines for swing control.
Sequence:
Lift end trucks to runway level and set temporarily on blocks.
Rig the bridge girder(s) and make the main lift.
Use drift pins to align flange holes; torque to spec.
Verify camber and bridge square.
Before anyone celebrates, bump-test long-travel motors with temporary power (under permit): ensure correct rotation and brake release. Lock out after test.
The Heart of the Lift
Trolley installation: Hoist/trolley arrives pre-assembled or as modules.
Hoist reeving: Lubricate wire rope; verify dead-end terminations.
Limits & load devices: Set upper/lower limit switches.
Cross-travel adjustment: Align trolley rails on a double-girder.
Pendant/remote: Install pendant festoon or pair radio receiver; function-test deadman and two-step speed controls.
A smooth trolley with a quiet hoist is a sign of good alignment. Fix the mechanics first.
Electrics & Controls
Power supply: Conductor bars with collectors or a festoon system.
Drive setup: Enable S-curve profiles for precise positioning.
Interlocks & safety: Zone limits near doors or mezzanines.
Cable management: Secure junction boxes; label everything for maintenance.
Commissioning crews love clean labeling and clear folders. If it isn’t documented, it didn’t happen—put it in the databook.
ITP, Checklists, and Sign-Off
Inspection Test Plan (ITP): Hold/witness points for rail alignment, torque, electrical polarity, limit settings.
Torque logs: Record wrench serials and values.
Level & gauge reports: Note any corrective shims.
Motor rotation & phasing: Confirm brake lift timing.
Functional tests: Jog commands, inching speeds, limits, overloads, pendant/remote range.
QA/QC is not paperwork—it’s your warranty in a binder.
Ready for Work
Static load test: Apply test weights at the hook (usually 100–125% of rated capacity per spec).
Dynamic load test: Check sway, braking distances, and VFD fault logs.
Operational checks: Emergency stop shuts down all motions.
Training & handover: Operator basics, daily pre-use checks, rigging do’s & don’ts.
When the logbook is clean, the crane is officially in service.
Where These Cranes Shine
Construction & steel erection: handling long members safely.
Oil & gas & power: generator and turbine assembly.
Steel mills & mcc construction foundries: hot metal handling (with the right duty class).
Warehousing & logistics: high throughput lanes.
Floor stays clear, production keeps flowing, and precision goes up.
Do It Safe or Don’t Do It
Rigging discipline: dedicated signaler and stop-work authority.
Lockout/Tagout: test before touch every time.
Fall protection & edges: approved anchor points, guardrails on platforms, toe boards.
Runway integrity: no cracked welds, correct bolt grades, proper grout.
Duty class selection: overspec when uncertainty exists.
A perfect lift is the one nobody notices because nothing went wrong.
Troubleshooting & Pro Tips
Crab angle/drift: verify end-truck wheel diameters and gearbox mounts.
Hot gearboxes: misalignment or over-tight brakes.
Rope drum spooling: dress rope and reset lower limit.
Pendant lag or dropout: shield noisy VFD cables.
Wheel wear & rail pitting: add rail sweeps and check clip torque.
Little noises are messages—listen early.
Fast Facts
Overhead vs. gantry? Bridge cranes ride fixed runways; gantries walk on the floor.
Single vs. double girder? Span and duty class usually decide.
How long does install take? Scope, bay readiness, and tonnage rule the schedule.
What’s the duty class? FEM/ISO or CMAA classes define cycles and service—don’t guess; size it right.
What You’ll Take Away
If you’re a civil or mechanical engineer, construction manager, shop supervisor, or just a mega-project fan, this deep dive makes the whole process tangible. You’ll see how small alignment wins become big reliability wins.
Need a field bundle with JSA templates, rigging calculators, and commissioning sheets?
Grab the installer pack so your next crane goes in cleaner, faster, and right the first time. Save it to your site tablet for quick reference.
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