Ballast for railway tracks provides the support for sleepers. For effective support, the individual rocks must be made to interlock and key-in to each other. The Vibropak from HMA Materials Handling is a spot tamping machine designed to consolidate either new, worn or loose ballast under concrete, steel or timber sleepers. It is rapidly deployable and incorporates suspension suitable for medium-speed travel.

The Vibropak from HMA Materials Handling incorporates several functions to enable the operator to compact the ballast. Each work head has four tines that are vibrated at high frequency by a rotating eccentric. The work heads, which can be operated independently, when plunged into the ballast cause the material to fluidise, and when squeezed flow under the sleeper.

The squeezing mechanism provides variable forces, with a minimum at time entry, to a maximum when forcing ballast under the sleeper. All of the controls for the functions, either foot or hand operated, are positioned to ensure high machine productivity and operator comfort. The machine is powered by a diesel engine providing hydraulic power to all the functions including rail clamps and centre jack.