Walking Systems
Walking Machinery
x-swing foot
king pin foot
compacjac foot
super-x foot
super-stomper foot
sidekick foot
reciprocating foot
Walking System Configurations
low pro
Pony-Sub Walkers

A Chassis for Oil Rigs and More

Entro Pony-Sub walkers are built from a set of boxes or frames designed around our walking feet. These boxes pin together either directly or with spreader beams. Two- and four-frame versions are the most common.

The entire drilling rig can be placed as-is onto an Entro Pony-Sub for hassle-free installation. Only minimal changes to the rig are necessary to make a safe connection because the sturdy structure of the Pony-Sub supports the entire length of the drilling rig substructure. The Pony-Sub also provides extra room for access to the walker. This clearance allows for large walking feet to reduce ground-bearing pressure. To achieve the lowest pressure, combine the Pony-Sub with a Super Stomper walker. Even with large feet, this walker maintains the ability to move in any direction.

Retrofitting and Modification

Entro walking machines can be factory installed into new Entro Pony-Subs, or can be custom engineered to retrofit into existing rigs. Originally designed for box-on-box drilling rigs, our Pony-Sub has been deployed under a variety of drilling rigs thanks to the simple installation.

The 4J3500KP Pony-Sub walking system is designed to efficiently mobilize land-based, box-on-box drilling rigs for hole-to-hole rig moves.

The Pony-Sub can be used with all of our walking systems including the King-Pin and X-Swing. The height of the Pony-Sub structure can be varied for different styles of rig, shipping configurations, or stress and deflection requirements. If a short Pony-Sub is required, the CompacJac walking foot can be employed.


The Pony-Sub can be specialized for many applications. The StrongBack and Low Pro Pony-Sub walkers were developed for the needs of the oil field. However, the Pony-Sub concept can be adapted to any large load, whether in construction, mining, energy or raw material handling. The job site or backyard can be carried with you when you use a Pony-Sub with a drop in platform or full tabletop.

Customization and Features

  • System can be customized at customer request
  • StrongBack and Low Pro
  • Fully tested before shipment; place your load and start walking on the first day
  • Includes wireless remote control with back up and a manual back up
  • AutoWalk and AutoLift
  • Self-supporting rig-up spreaders can also be deployed without machinery and stow on the side of the box during shipment


This product may be protected by patents and applications. Please refer to the following: https://entro-eng.com/about/patents/