Today, the central focus of a modern maintenance strategy is on economical deployment of track maintenance machines. In order to utilise track possessions as fully as possible there is a need for high-capacity machines. Nowadays, the trend is going towards combination machines which combine several stages of work in one machine. A good example of such a machine is the RU 800 S the world’s first combination machine for continuous track renewal and simultaneous ballast bed cleaning with supply of new ballast.

Old-tie pick-up unit

Ballast excavating & profiling chain

Shoulder cutter

New-tie pick-up unit

Ballast storage car

Placing ballast

Screening units

The heart of the machine is the track relaying machine itself with an integrated ballast bed cleaning system. During working operation the central undercarriage is raised by a spindle and the two four-axled bogies are displaced by 4.500 mm to the front or to the rear in order to obtain a clear working area of 45 m. This long space ensures a smooth bending line of the rails during removal and laying.

The old-tie pick-up unit picks up the old ties in continuous working action and transports them on conveyor belts to the old-tie transfer platform. Then the ballast is excavated using an excavating chain which can achieve an excavating depth up to 800 mm below top of rail. The old ballast is taken on conveyor belts to the double screening unit. The screens separate the spoil from the re-usable ballast. Then the cleaned ballast and the new ballast is taken back for insertion. A plough distributes the ballast in the ballasting area, taking care that the area in the centre of the track is lower to avoid centrebound ties. Then the inserted ballast is compacted using plate consolidators. Immediately after this, the new ties are placed at the correct tie spacing. Due to the limited space available, the new ties are transported through the machine parallel to the track axis. For that reason the new ties are turned, two at a time, inside the machine just after the transfer platform and turned back just before the laying unit. The supply of new ties and evacuation of old ties is carried out by two gantry units which can pick up 30 ties at a time. The gantry units run on rails mounted on the sides of the cars. For transfer travel two 4-axled wagons with arched frames are used to transport the gantry units. During work the remaining rail fastenings are loosened underneath the frame of the first wagon. The drive engines are also mounted on this wagon. The second wagon carries the measuring equipment and a water tank.

After the relaying machine follows the shoulder excavation car. Two shoulder cutters pick up the remaining ballast and pass it to conveyor belts for transport to the screening car. The excavating width can be varied between 600 mm and 1.250 mm depending on the cutter head.

The following ballast storage and ballast distributing car is equipped with a 30 m³ buffer store for new ballast and/or cleaned ballast. The floor of the hopper is designed as a conveyor belt. Ballast distributing devices for the shoulders and for the tie cribs are mounted behind the hopper. In addition to this, an automatic action eight-spindle power wrench is mounted on the ballast hopper car which is suspended on the main frame so that it is longitudinally displaceable and tightens the rail fastenings in cyclic action.

When Fastclips are used, the eight-spindle module is replaced before start of work by a Fastclip clipping unit.

The ballasting and power wrench car is followed by the screening car. Two eccentric vibratory screens are in operation, as already used on other highcapacity ballast cleaning machines. The screens separate the re-usable ballast from the spoil. A total screening area of 46 m² guarantees the required output.

Material conveyor and hopper units are used to transport the spoil and the ballast. These are coupled to the end of the machine. To transport the spoil, the new-ballast MFS is equipped additionally with a conveyor belt.

• Rail fastenings are released in the worksite area before arrival of the RU 800 S.
• Rails are cut and fishplated together provisionally.
• RU 800 S arrives at the worksite and is prepared for operation.
• Remaining rail fastenings are released.
• Old rails are lifted and spread out.
• Old ballast bed is excavated to a width of 4.000 mm and a depth of 800 mm below top of rail, the guided chain also produces the desired slope of formation for correct drainage.
• Cleaned ballast is inserted (adding new ballast, if necessary).
• Cleaned ballast is distributed and compacted, the ballast bed is ploughed deeper in the middle of the track to prevent centre-bound ties.
• New ties are laid.
• The new rails are laid on the ties, the rear four-axled bogie of the relaying machine is already running on the newly laid track at this point.
• Any ballast material not yet cleaned is picked up from one or both shoulders over a width of 600 to 1.250 mm.
• Ballast bed material is cleaned.
• Old rails are moved over into the centre of the track (if required).
• Rail fastenings are applied.
• Cleaned (and if necessary new) ballast is distributed in the tie cribs and on the shoulders.
• New ballast is added as required from the towed MFS units.
• Track parameters of the newly laid track are measured and recorded.

• Continuous track renewal with simultaneous cleaning of the ballast
• Track renewal without ballast cleaning
• Track renewal with complete exchange of ballast
• Tie exchange with ballast cleaning without exchange of rails
• Exchange of ties only
• Shoulder cleaning without track renewal

• Economical utilisation of track possessions due to simultaneous operation of track renewal and ballast bed cleaning
• Technologically correct sequence of work: cleaning before renewal
• Optimisation of quality and costs
• Lowering of the new track is possible compared to the old track
• Ballast bed cleaning possible without problems, even in restricted areas such as station platforms
• Careful handling of the materials being removed and laid
• All re-usable ballast material is managed within the machine, therefore no heaps of ballast in the track area
• Low bending stress of the rails due to large spans
• Exact laying of the ties in the specified positions
• No hindrance of the adjacent track because all material is transported on the track under construction
• Personnel is reduced to a minimum

RU 800 S

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