Two newly designed high output ballast cleaning systems (HOBCS) were ordered by Network Rail to meet the requirements of the track renewal strategy. The first of these systems has now arrived completely in the U.K., the second system will be delivered in the course of next year.
The HOBCS high output ballast cleaning system consists of an RM 900 ballast cleaning machine with supply of new ballast, two power wagons as traction vehicles and 44 material conveyor and hopper units, 36 of which are MFS-D for through-loading and the remaining 8 are MFS-SB with slewing unloading conveyor belt. The entire system is designed for a cleaning output of up to 900 m3 per hour or 400 metres of track per hour.
RM 900 high capacity ballast cleaning machine
Successful operation of the entire HOBC system requires a high output of the ballast cleaning machine which forms the heart of the HOBCS. This means that all individual components must be co-ordinated to this high output. As on all cleaning machines made by Plasser & Theurer, this also applies in the case of the RM 900: the excavating chain producing the working capacity with the appropriate cleaning depth, the matching screening area which assures the quality of the reclaimed ballast, efficient transport of material within the machine, a measuring system for precise control of the machine, and the added advantage of short set-up times for operation even in short intervals between trains.
Status-related addition of new ballast
The conveyor system of the RM 900 is able to take over the new ballast carried in the material conveyor and hopper units and place it in the track together with the cleaned ballast. The proportion of new ballast can be adapted according to the prevailing situation. The track is filled immediately with the amount of ballast needed for the first tamping pass.
The MFS units are pulled by the power wagons during working operation and carry out the handling of spoil and new ballast. Besides the option of ballast bed cleaning, the RM 900 also performs installation of geotextiles and, if required, total excavation of the ballast bed material.
During the design of the HOBC system, particular attention was focussed on maximum output (despite the tight clearance gauge in the U.K.) together with great accuracy of laying of track.
In May 2004 extensive trials were performed with the RM 900 high capacity ballast cleaning machine in the area of Weissenbach, Austria, together with five MFS units and a power wagon. All adjustment work and acceptance tests were carried out successfully. The approval tests for the journey on British tracks were also performed in Linz for the first time.
In June the cleaning machine was transported to England together with the other vehicles through the channel tunnel. The final tests and approvals were carried out in the course of the summer. The owner of the machine, Network Rail, has commissioned the joint venture First Engineering and Swietelsky with operation and maintenance of the machine and preliminary operations will commence after the summer.