Stone blowing
An intrinsic part of the Howesian school of track maintenance, stone blowing is the injection of measured quantites of 10mm chippings under the sleepers to remove voids and produce a level road.
The FR has the prototype "hand-held" (actually a two-man lift!) stone-blower, simply a large diesel powered fan. This has a hose attachment into which stones are poured and carried along in the airstream following the Venturi effect - in a similar way to a perfume spray!
A typical stone blowing team involves an advance man jacking the track, one or two Kangoing in steel square hollow sections to hold the hose in place, one working the hose, one delivering buckets of chippings and maybe a few more helping the whole process forward. The noise of the stone-blower, generator for Kangos and the Kangos themselves means that ear-defenders have to be worn, so all communication is by hand signal. Despite this, when a close-knit team has got going it works like a machine.
Unlike Network Rail's satellite-linked, CDROM, laser-guided machines that pour in stone until a level is reached, the amount of stone is carefully measured in an old enamel pint mug, the quantities calculated by eye using Sighting Boards.