hydraulic skidding fundamentals

All Hydra-Slide systems feature a ratchet track design, so when the cylinders are retracted, they will automatically reset into the next ratchet slot position for the next push cycle.
Hydra-Slide skidding systems are a fully engineered, off-the-shelf solution for moving heavy loads with safety and simplicity. They’ve been proven in the roughest field conditions and are designed and built with the rigger in mind. Every system meets stringent CE safety requirements, is built by certified manufacturing shops, and is rigorously inspected before leaving the warehouse. Every system includes detailed O&M manuals, stamped drawings, and track-capacity charts.
Hydra-Slide skidding systems are one of the safest methods for moving heavy loads horizontally. The tracks are very low profile, keeping the load close to the ground and moving along a guided path. The load is never freely suspended. When used as intended, they don't require any winches, holdbacks, or other external force/restraint of any kind. They are controlled by a single operator and there is no need for any personnel to be close to the load while it is moving.
Our systems are designed based on a 0.15 - 0.20 friction coefficient. The relatively high friction values increase the safety of the move by virtually eliminating any risk of uncontrolled movement or runaway.
  • Move loads from railcar to transporter/truck
  • Move loads from truck to pad in live substation
  • Install machines or equipment inside plants
  • Move equipment in confined spaces
  • Handling of sensitive/delicate equipment
  • Slide equipment to within reach of a crane for removal/installation at height.
  • Slide equipment on an elevated platform for removal/installation at height.
  • Transformers
  • Boilers
  • Generators
  • Gas Turbines
  • Tunnel-boring machines
  • Bridge sections or girders
  • Injection moulding machines
  • Compressors
  • Heat exchangers
  • HRSG modules
  • Process Vessels
  • Substation components
  • Modules/prefab buildings/storage tanks
The speed of a skidding operation is almost totally determined by the flow rate of the hydraulic pump being used, and the capacity (volume) of the push/pull cylinders. For example, a system with 30-ton cylinders (which includes our XLP150, LP350, and HT300 systems) and a pump with a flow rate of 1 gallon/min per cylinder will move the load approximately 89 feet (27 meters) per hour.
Both our Heavy Track (HT) and Low Profile (LP) skid system models offer a very safe and effective way of moving heavy loads, but depending on your intended application, a particular model may be better for you. The LP design is perfect for moving loads where there is restricted access or overhead clearance and good surface conditions—for example, inside a plant or moving loads over a well-supported surface. All components are hand-portable and easy to transport. The HT systems are excellent for moving loads in rougher field conditions, or where the track may need to span unsupported distances, such as moving loads from railcars to transporters, across open areas, or on uneven ground. We are always happy to discuss your specific requirements and provide information to help you choose.
Longer stroke push cylinders would move the load at almost the same speed as shorter cylinders, because a cylinder that is twice as long takes twice as long to extend and twice as long to retract. Shorter cylinders take up less unusable space on the track, which could be critical in tight areas. Shorter cylinders are also easier to realign at the end of each stroke, reducing the risk of uneven movement, sideloading, and binding in the track.
No additional lubricants are recommended or required. The system is shipped with a layer of brush-on graphite, as well as an extra can for future applications. This is the only lubricant required.
Regular maintenance of the system includes brushing away any surface rust that accumulates, and applying a layer of graphite to the slide surface and the bottom of the slide shoes. The frequency of this maintenance will depend on how much the system is used and the storage conditions. Our guideline is that graphite should be reapplied when bare steel starts being visible or when surface rust begins collecting on the slide surface. Any surface rust should be dry-brushed off and then a thin layer of graphite should be applied with a brush or roller. The relatively high friction factor of graphite is a safety feature of these systems; it reduces the chance of unwanted movement of the load as force must always be applied to the load to move it.
No, the weight of your load doesn't‎ have an effect on the speed of operations. Skidding and jacking speed is based purely on the pump flow rate and the size of the cylinders.
This is the difference between the cylinder's rated capacity and the system's full load-moving capacity. The 30-ton rating on the push/pull cylinders is based on the maximum push force the cylinder can exert when operated at 10,000 psi, and is not to be confused with the system load carrying capacity.
All of our Skid Systems are rated based on the maximum load weight that can be carried on the system and is able to be moved horizontally by the push/pull cylinders.
The force required to move a load along the slide surface is based on the friction factor at that surface. Our systems all have a friction factor of 15–20%. For a full explanation, please watch this video.
Yes, a slide system can be placed on the top lift beam of a lifting tower or gantry to provide side-shifting capability.
All Hydra-Slide system tracks are bi-directional and can move the load in either direction. The preferred method for changing direction is to remove the cylinder assembly from the leading end of the slide system and reposition it on the back end of the system. Pushing is superior to pulling when possible. There may be times when there is not sufficient space to insert the cylinder assembly on the desired end of the system, in which case the system's push and pull functions may be required.
We provide hard-copy O&M Manuals complete with Troubleshooting and repair/maintenance information for all of our systems. Addtionally, you can always call us directly with questions and a technician will be happy to assist.
We know that sometimes, project schedules are tight, and sometimes, tenders are awarded with little time for planning and equipment acquisition. We make every effort to work with your project schedule. Many of our systems are kept in stock for quick delivery, but some larger orders and customized systems may take a few weeks to fabricate.

heavy track skidding systems

Our Heavy Track skidding systems are a simple, effective tool for moving heavy loads horizontally. The load, whether it is a transformer, heat exchanger, or some other heavy equipment, sits on skid shoes on a guided track. The loaded skid shoes are then pushed along by hydraulic cylinders.
Our Heavy Track systems are made of rigid steel track sections and skid shoes, both of which a coated with dry graphite on their slide contact surfaces. The graphite is used for several reasons: first, it provides a 0.15 - 0.20 friction coefficient. The relatively high friction values increase the safety of the move by virtually eliminating any risk of uncontrolled movement or runaway. Secondly, because it is a dry lubricant, any contamination, grit, or other debris that falls on the tracks can simply be brushed off and does not become embedded in the system, preventing damage to the system surfaces and hydraulics. It is also non-hazardous and readily available for periodic maintenance.
Our Heavy Track systems can support heavy loads over a considerable span, such as a containment well, pit, or during transloading operations. The distance that can be safely spanned can be calculated by using the system's engineered Track Capacity chart and the weight of the load being moved. Track connection joints must always be fully blocked. See this video for a guideline on these span distances.
These systems require very little maintenance. They should be kept clean and handled with care so as not to damage any parts or sliding surfaces. When not in use, all components should be stored in their provided storage racks and boxes, protected from the environment. The surfaces will require an occasional reapplication of graphite. If surface rust collects on the slide surfaces, simply brush it off with wire pad. The most sensitive parts of the system are the hydraulic cylinders. Follow the Operating Manual's recommendations for inspecting and servicing the hydraulics components of the system to avoid malfunctioning and the risk of introducing contaminants into your hydraulic system.
Our standard HT300 system package includes:
50 feet (15m) of double track
4 Push/Pull skid shoes with safety pins
2 hydraulic cylinder assemblies
Connecting bars & pins
Safety stop blocks
Graphite lubricant
The push cylinders, accessories, and connecting hardware come packed conveniently in a steel Toolbox for storage and transport
The skid shoes and stop blocks are packed into a storage rack for easy mobilization
Additional track sections and components are also available
Our standard HT500 system package includes:
50 feet (15m) of double track
4 Push/Pull skid shoes with safety pins
2 hydraulic cylinder assemblies
Connecting bars & pins
Safety stop blocks
Graphite Lubricant
The push cylinders, accessories, and connecting hardware come packed conveniently in a steel Toolbox for storage and transport.
The skid shoes and stop blocks are packed into a storage rack for easy mobilization
Additional track sections and components are also available
Our standard HT1000 system package includes:
50 feet (15m) of double track
4 Push/Pull skid shoes with safety pins
4 hydraulic cylinder assemblies
Connecting bars & pins
Safety stop blocks
Graphite Lubricant
The push cylinders, accessories, and connecting hardware come packed conveniently in a steel Toolbox for storage and transport
The skid shoes and stop blocks are packed into a storage rack for easy mobilization
Additional track sections and components are also available

Low Profile Skidding Systems

Our Low Profile skidding systems are a simple, effective tool for moving heavy loads horizontally. The load, whether it is a transformer, heat exchanger, or some other heavy equipment, sits on slider plates on a guided track. The push/pull cylinder is connected to these slider plates with a pusher head. This is the piece of the system that makes contact with the load and is then pushed along by hydraulic cylinders.
Our LP350 system has the same graphite coated steel slide surfaces as our Heavy Track systems.The underside of the LP350 track sections and slider plates are both coated with dry graphite. The graphite is used for several reasons: first, it provides a 0.15 - 0.20 friction coefficient. The relatively high friction increases the safety of the move by virtually eliminating any risk of uncontrolled movement or runaway. Secondly, because it is a dry lubricant, any contamination, grit, or other debris that falls on the tracks can simply be brushed off and does not become embedded in the system, preventing damage to the system surfaces and hydraulics. It is also non-hazardous and readily available for periodic maintenance.
UHMW-PE (Ultra High Molecular Weight Polyethylene) sliding pads contacting a smooth steel surface. This is a clean system that produces no dust, and can be built with stainless steel if required.
Our Low Profile systems (both the XLP150 and LP350) require full support when loaded. They are intended for usage on flat, well-supported surfaces such as concrete, beams, or timbers. We offer optional engineered Aluminum Beams for enhanced structual support when using Low Profile systems.
Our standard XLP150 kit includes track sections, slider plates, all connecting hardware, and hydraulic push/pull cylinders. The full system is contained in a storage box for greater protection and portability. We can accommodate most requests for additional components or different track lengths. The hydraulic power unit and hoses are offered separately.
Our standard LP350 kit includes track sections, skid shoes, all connecting hardware, and hydraulic push/pull cylinders. The LP systems also include a storage container for greater protection and portability. We can accommodate most requests for additional components or different track lengths, etc.—everything needed to move a load except the hydraulic power unit and hoses, which we offer separately.

Hydraulic Power Units

Hydra-Slide skidding systems, turntables, alignment shoes, and climbing jacks will operate with most 10,000 psi (700-bar) double-acting pumps. We offer a complete line of both synchronous and conventional power units to suit almost any application. Some of our customers already own suitable power units; our hydraulics specialists can assess your existing unit for compatibility with our systems if required.
Conventional power units have a single oil supply circuit. It may be split into more than one outlet circuit, but they are connected, and act as one. The pressure will remain constant in all lines but the flow rates may be different. If the load is heavier on one side, the cylinder with the least load will advance more than the heavier side. When jacking, it is necessary to jack only one end at a time and ensure that the load can never tip. When skidding, it is necessary to ensure that both cylinders advance at nearly the same rate. Our conventional power units are equipped with flow control valves to help control the flow rates to each push cylinder.
Synchronous power units have multiple but independent oil circuits. The circuits are not connected to each other and will give equal flow to each line regardless of the weight of the load or the pressure in that circuit. We accomplish this by using specially designed piston pumps, valves, and control devices. This allows the user to raise almost any load straight up, safely and equally at all points, without the risk that one side will raise faster than the other. We have also employed special devices on the return side to ensure that the load can be lowered evenly, slowly, and always under control.
The type of power unit that would best suit you is primarily decided by your expected type of usage. If you are planning frequent multi-point lifts, a synchronous system may be the best investment. We manufacture 4, 6, or 8 port units in diesel, propane, or electric models. If you anticipate only occasional usage, or primarily skidding functions, not multi-point jacking, a small conventional unit may suit your needs very well. If you expect to use your equipment frequently, or in more demanding situations, you may want to consider a synchronous power unit. We are always available to discuss your needs and help you make an informed decision.
Synchronous power units are simpler and safer than some other hydraulic pumps for jacking and skidding operations. First, they are designed for field conditions—no computers, wires, or transducers to set up or calibrate. The system is built with manual, mechanical controls. Second, they provide synchronous movement of cylinders on individual ports. The ports are not connected to each other and will give equal flow to each line regardless of the weight of the load or the pressure in that circuit.
One of the keys to the synchronous function is the split-flow, checkball piston pump. It incorporates multiple independent pistons driven by a common shaft, which ensures that each piston generates the same flow rate. Because of the relative incompressibility of oil and the sealing ability of the checkballs, the flow rate is virtually unaffected by the pressure.

All of our Hydraulic Power units are equipped with pressure relief valves to prevent over-pressurization within the system. These valves are typically adjustable from zero up to a maximum of 10,000 psi (700 bar).

Our Hydra-Pac synchronous power units have an operator-adjustable pressure relief valve on each circuit. These valves can be individually set to suit the requirements of the job and to provide for additional safety. In addition, there is an overall non-adjustable system pressure relief valve that limits the maximum generated pressure to 10,000 psi (700 bar).

Yes it is. Our Hydra-Pac power units are equipped with counterbalance valves on the pressure ports. These function to control the lowering of a cylinder that is under load by using the return side pressure to open the valve. They act as a brake. When using single-acting jacks, there is no return line, and so we control the lowering speed by using a separate flow control. The flow control valves allow free flow in one direction (towards the cylinder) and control the flow in the other (back from the cylinder). The hydraulic hose is connected from the return port of the pump (with the flow control valve) to the cylinder port. The flow control valve is closed so that oil can only flow to the cylinder. When you wish to lower the cylinder, the flow control valve is opened gradually to allow oil to flow out of the cylinder and lower it in a controlled manner. Keep in mind that when lowering single-acting jacks, they will not necessarily be synchronized.

Hydraulic Jacks

Hydra-Slide supplies both steel jacks in capacities ranging from 50 tons to 200 tons, as well as aluminum jacks in capacities from 30 to 150 tons. Aluminum jacks are about half the weight of standard steel jacks, so they are much easier for your riggers to handle during lifting/lowering operations. To decide what capacity of jack is required for your application, remember that it is good practice not to exceed 80% of the jack's rated capacity.
The choice of jacks will depend on the weight of the load to be lifted/lowered, and how many jacks will be used. Remember that it is good practice not to exceed 80% of the jack's rated capacity. For example, for lifting a 300-ton load: four 100-ton cylinders would provide 400 tons of total lift capacity. The 300-ton load would be at 75% of the jacks' capacity.
Climbing Jacks are most advantageous in situations requiring higher lifts, or where you want to jack using single blockpiles. Climbing jacks require only a single blockpile for each jacking point, as opposed to conventional jacking that requires a jack pile and a separate support pile. This also eliminates the effect of timber piles compressing and expanding as the load is alternately put on and off the piles.
A climbing jack incorporates an inverted double-acting cylinder inside a special wide housing. The rod has a wider foot attachment. As the cylinder is extended, Ekki timbers are placed under the sides of the housing. The cylinder is then retracted and more Ekki timbers are placed under the rod foot. The cylinder is extended again, and this time, a row of Ekki is placed under the housing but at 90⁰ to the first row. This sequence is continued until the load reaches the desired height. For lowering a load, the above sequence is simply reversed.

Ekki Timbers

This wood has exceptional strength and resistance to crushing or bending, and is ideally suited for jacking and blocking applications. Ekki is a West-African hardwood that is over three times stronger than white oak or fir. It is naturally resistant to insects, is non-porous, and does not rot. These timbers do not become structurally compromised over time like traditional hardwood does. Our timbers are a standard size of 10cm x 10cm x 1.0m, and weigh only about 11kgs each. (4" x 4" x 40" x 25 lbs). They are much smaller, lighter and easier to handle than conventional timbers.
As an initial investment, Ekki may be more expensive than other traditional woods. However, it will last for years without becoming structurally compromised, allowing for safer operations because there is no risk of blocking, crushing, or yielding. They also save time by being much lighter and easier to use for blocking and jacking applications.
We work with a Mill in Holland that produces these timbers from fresh logs. We order by the Container load and handle all documentation and import requirements. The timbers include Phytosanitary Certificates, and when required, Certificates of Origin. To import Ekki timbers into the USA, a permit is required by the USDA. We give our American customers all the information they need to apply for and receive this free permit before we deliver.

Specialized Hydraulic Equipment

Our engineered hydraulically-powered turntables make rotating machines such as transformers or generators simple, fast, and accurate. They incorporate a reversible, hydraulically powered rotating mechanism for precise control. Like our skidding systems, they do not require any external holdbacks or winch lines, and are operated remotely. All personnel stay at a safe distance from the load during rotation.
Yes, there are a number of ways to achieve a higher capacity on a standard skidding system. The capacity of the system is based on the amount of push force you use (the number of cylinders). Adding additional cylinders will increase the push/pull capacity on the system. A third line of track complete with its own skid shoes and push/pull cylinder will also increase the system capacity. If a greater spanning distance is required, increasing the number of skid shoes will spread the weight of the load over a greater area and will allow longer distance spans between blocking. The Track Capacity Chart determines the allowable span based on weight on each skid shoe. Increasing the number of push cylinders and shoes will increase your system capacity as well.
The Crossover system allows a grid to be set up in advance of the move, making the move itself more efficient, and facilitating multiple moves along the same path.
The Crossover system allows direction changes without the need to jack up the load or reposition any equipment, and the orientation of the load remains the same. A turntable also allows direction changes while skidding—however, the orientation of the load will change as well.
Our Crossover system has an innovative skid shoe design, incorporating a removeable section. This small, manageable section can be inserted on any side of the skid shoe, allowing skidding in four directions.
Jacking Load Shoes are load-compensating skid shoes designed to work with our Heavy Track skidding systems to provide increased load-handling capability.
Jacking Load Shoes both increase the maximum load capacity of our skidding systems, and work to equalize the load distribution across all points. The load can also be raised and lowered during skidding operations.