stoneblower

From stone +‎ blower.

stoneblower (plural stoneblowers)

1. (rail transport) A machine that automatically lifts and packs the sleepers of a railway with small-grade ballast, which is blown under the sleepers to level the track.
   • 2021 April 21, Stefanie Foster, “Network Rail pledges major contribution to Rail Live 2021”, in RAIL, number 929, page 19:

     NR also plans to display a stoneblower from its track treatment fleet at the show. [...] They are known as stoneblowers because they use compressed air to 'blow' extra stones under the sleepers where required, to correct the level of the track.