Double girder overhead traveling crane North American Industries

Girder Stength
A common misconception is that double girder bridge cranes are more durable. Based on the CMAA (Crane Manufacturers Association of America) specifications, both single and double girder cranes are equally rigid, strong, and durable. This is because single girder cranes use much stronger cross girders than double girder cranes, and single girder cranes have lateral bracing.

The Difference is in Hook Height
The principle difference between single and double girder cranes is hook height (how far above the floor your hoist will lift). Double girder cranes provide better hook height. Double girders typically allow 18-36 inches higher lift.

Double girder cranes can provide more lift, because the hoist is placed between the cross girders rather than under them. Therefore, the depth of the cross girder is gained in switching to double girders.

Cost Considerations
Single girder cranes may cost less for several reasons:

Only one cross girder is required
The trolley is simpler
Fright expenses are reduced
Installation is faster
Runway beams are lighter

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