About Harsco Rail. UK

Stoneblower Operations

The Stoneblower is a revolutionary machine developed specifically as an alternative to traditional tamping methods for the restoration of track’s vertical and lateral alignment. The machine utilizes a process which pneumatically injects ballast under the sleeper to achieve track positioning to an accuracy of 1.0 mm without disturbing the pre-existing compacted foundation. The result is a smooth track surface which is immediately available for unrestricted line speeds. The Stoneblower is the culmination of many years of research and development by Harsco Rail in cooperation with Network Rail. The machine has undergone extensive testing to meet demanding requirements and has demonstrated the ability to significantly extend the time
required between track maintenance cycles.

Stoneblower Special Features

Complete vertical and lateral track design capabilities.
Automatic indexing with two sleepers treated simultaneously.
Automatic sleeper position sensing.
Computer accessed calibration routines for reference system, workheads and stone supply system.
Dual encoder system for distance and feature recording.
On-board crane loads machine completely with stone in less than one hour.
Complete track recording system.
Operator interface via touch screen monitors.
Diagnostic system to monitor all machine functions including drive and stone supply system.
Paint marking system.
Designed and manufactured to rigorous reliability standards to ensure required machine availability and reliability levels.
Post maintenance track quality monitoring.

Measurement

The machine travels over the site at up to 10 mph measuring the pre-maintenance condition of the track.

Design

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.

Maintenance

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.

STONEBLOWING ADVANTAGES

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 Stoneblower’s 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.

Stoneblower General Specifications

Average Output - 440 meters / hours (1,400 feet / hour)
Gross Weight - 113 tonnes (124 tons) carried on three bogies
Maximum Axle Load - 18 tonnes (20 tons)
Length - 32.2 meters (106 feet)
Travel Speed - 100 kph (60 mph) maximum
Measuring Speed - 16 kph (10 mph) maximum
Engine - Cummins KTTA19C, 522 kilowatt (700 horsepower) Ck 1,950 rpm
Auxiliary Power Unit - Cummins 4133.9 diesel, 28 kilowatt electrical output
Track Lifting - 0 to 80 mm (0 to 3.2 in.)
Track Slewing - 0 to 80 mm (0 to 3.2 in.)
Minimum Working Radius - 150 meters (500 feet)
Fuel Capacity - 4,500 liters (1,200 gallons)
Hydraulic Tank Capacity - 950 liters (250 gallons)
Stone Capacity - 16 tonnes (18 tons), Size #6-approximately 20 mm (0.8 in.), LA Abrasion Index 11-19
Stone Delivery - 0.5 to 22 kg (I to 48 lb.) per sleeper end
Automatic Index Distance - 1 sleeper pair
Index Time - 3 seconds
Blowing Time - 3.0 to 11.0 seconds