Jacking and skidding is a heavy rigging method that moves loads without a crane. Hydraulic jacks raise the load in stages with cribbing built underneath, the load is lowered onto skid shoes or rollers on a prepared track, and hydraulic push-pull units slide it horizontally in controlled strokes. Hydraulic gantries do a similar job when a load has to be lifted and traveled. The method is used indoors, under low headroom, in tight substations, and anywhere a crane can't set up or reach.
When people picture heavy rigging, they picture a crane. But a lot of the heaviest moves in plants, substations, and building basements never see one. They happen on hydraulic jacks, cribbing, skid track, and gantries, slowly and deliberately, with every inch controlled.
What is jacking and skidding?
Jacking raises or lowers a heavy load using hydraulic jacks, usually in small increments with cribbing (hardwood or steel blocking) built up underneath so the load is never supported by the jacks alone. Skidding moves the load horizontally: it rests on skid shoes or beams sitting on a track, and hydraulic push-pull units slide it along in short, controlled strokes.
Together they let a crew raise a transformer off a trailer, slide it across onto its foundation, and lower it into place without anything ever hanging from a hook.
How does a jack-and-slide skidding system work?
- Prepare the track. Skid track is laid on a surface that can carry the load, often over steel plate or mats, and shimmed level.
- Jack the load up. Jacks lift the load in stages at its designed support points, with cribbing added as it rises.
- Transfer to skid shoes. The load is lowered evenly onto skid shoes or beams sitting on the track, often with low-friction pads.
- Push or pull in strokes. Hydraulic units grip the track and extend, moving the load a short distance per stroke, then reset and repeat.
- Jack down at the destination. The load is raised off the shoes, the track is removed, and the load is lowered onto its foundation.
What is a hydraulic gantry?
A hydraulic gantry is a set of telescoping legs connected by a header beam. The legs extend to lift the load, and on many systems the gantry travels along track to move it horizontally before lowering it. Gantries are common for setting machinery and equipment indoors where headroom allows the lift but a crane can't get in.
Jacking & skidding vs gantry vs crane
- Jacking & skidding — very heavy loads, short horizontal moves, low headroom, no lifting overhead
- Hydraulic gantry — lift and travel loads indoors or in tight areas with enough headroom for the gantry
- Crane — open sites with room to set up, long reach, lifts onto roofs or over obstacles
When does jacking and skidding beat a crane?
- Inside buildings, where there's no way to bring a crane in
- Under low headroom that doesn't allow a lift
- In substations and plants crowded with energized or operating equipment
- When a crane large enough would need an unrealistic setup area or ground preparation
- When the load only has to move a short distance with very precise final positioning
What gets checked before a skid move?
Jacking and skidding concentrate enormous weight onto small contact areas, so the planning focuses on where that weight goes:
- Load weight and center of gravity so each jack point carries what you expect
- Support points on the equipment designed to take jacking loads
- Floor and ground capacity under jacks, cribbing, and track
- Track layout, level, and how the load is stopped and held at each stage
- Synchronization of multiple jacks or gantry legs so the load stays level
- Headroom and obstructions for the jacking height and travel path
What equipment is used for jacking and skidding?
Typical gear includes hydraulic jacks and climbing jacks, hardwood or steel cribbing, skid track and skid shoes, hydraulic push-pull units, low-friction pads, steel plate, and for lighter moves, toe jacks, machinery skates, and roller dollies. The right combination depends on the load, the distance, and the surface.
Bottom line
- Jacking raises loads in controlled stages; skidding slides them on track in short strokes.
- Gantries lift and travel loads where a crane can't work.
- The planning is about where concentrated loads land: floors, support points, and cribbing.
Need a heavy load moved where a crane can't reach? See our jacking, skidding, and gantry services and transformer rigging.