While the Plasser machine on the left is ubiquitous ballast packer, the second machine is very much more interesting. The machine lifts the very rails + sleepers that it is standing on (at the free space between the two bogies) and drags a chain under the lifted sleeper to loosen the ballast. Then it scoops, cleans, grades and returns the stones along the rails â all this while the machine is rolling slowly ! Yesvantpur, 2005-06-30. Apurva (iti@vsnl.com).