The machine travels over the site at up to 10 mph measuring
the pre-maintenance condition of the track.
On-board computers use the data collected during the measurement
process to determine the profile of the track and calculate
the lift, slew and stone quantity for each sleeper. The design
uses a pre-selected track quality level to minimize lifts
and the quantity of ballast required.
The machine moves down the track, in the opposite direction
to measurement, treating each selected pair of sleepers
simultaneously. At the completion of maintenance the machine
produces a record of pre and post-treatment track quality.
The resultant condition of the track is suitable for immediate
unrestricted line speeds.
Demonstrated Durability after stoneblowing,
the track remains in position on average four times
longer than track maintained by traditional tamping methods
because the existing compacted foundation beneath the
sleepers is undisturbed. Figure 1 shows the improvement
in durability for the stoneblowing process. This figure
was compiled from United Kingdom track data and shows
the increase in time between maintenance cycles varying
from five-fold improvement for track requiring tamping
every six months to a two-fold improvement for track requiring
tamping every thirty months.
Increased Productivity The Stoneblowers
track design system targets only sections that require
rectification and does not treat track with acceptable
pre-maintenance quality. For this mode of operation, production
rates can exceed 900 meters per hour with rates in typical
stoneblown sections averaging 440 meters per hour. Improved
Ballast Life Stoneblowing is significantly less
damaging to ballast as compared to normal tamping methods.
Tests conducted in the United Kingdom and repeated in
the United States have verified reduced ballast degradation.
Up to 4 kg of fines per sleeper are produced by one tamping
insertion while only 0.5 kg of fines per sleeper are produced
by an equivalent stoneblowing cycle. Figure 2 illustrates
the difference in ballast damage per sleeper for a total
of ten tamping insertions versus stoneblowing insertions.
Unsurpassed Quality Track immediately opened
at line speed after stoneblowing. On-board diagnostic
systems monitor quality during operation. Post maintenance
record of quality immediately available.