Re: Cleaning Ballast - Why do they need to do this?

["Reuben Farrelly" <reubie@bigpond.AAA.com>]

What exactly does the cleaning process involve in terms of what does the
cleaning machinery actually do?  Would I be right in guessing that it
essentially involves picking up the ballast and tossing it about, so that
the finer particles are moved nearer to the base, or does it involve somehow
removing the junk from the tracks completely?  Track maintenance gangs seem
to work with a fleet of several vehicles when they are doing work, what does
each one do?

As for weeds, well...a good example of weeds is on the Bendigo line, on the
up track at St. Albans Station.  Perhaps they are planning on harvesting the
seeds? ;)

Reuben


Bill <wguest@xtra.co.nz> wrote in message
37C3E246.5D040FE4@xtra.co.nz">news:37C3E246.5D040FE4@xtra.co.nz...
> Ballast cleaning (as distinct from simply putting new ballast under the
> sleepers) is done to remove some of the fine and dirty material from under
> the sleepers, thus lowering the track. By dirty material, I mean silts and
> organic soil; by fines I mean degraded ballast that is less than 25 mm.
Fine
> and dirty material does not support the track well, and encourages the
> growth of weeds that hasten the degradation of ballast and timber
sleepers..