Cut-outs for wheel detectors
HANNING & KAHL presents an innovation in the infrastructure-service sector. Cut-outs or openings have to be made in grooved-rail tracks for wheel-detector insertion. HANNING & KAHL is now using a new procedure to make such cut-outs / openings on existing tracks.
Up to now, cut-outs for wheel detectors were flame cut on site. The advantage: rapid implementation with existing equipment on standard tracks. The disadvantages: flame cutting in particular can cause track fractures due to surface notching and thermal influences.
Milling instead of drilling and flame cutting
As of now, HANNING & KAHL mills these cut-outs and openings on the construction site with ideal surfaces and round corners. This greatly reduces the danger of track fracture. One of the objectives is to make it easier to use the axle-counting technology in grooved tracks. Attempts to have cut-outs made on new tracks in advance by the manufacturer of the pre-fabricated track sections were not practicable. The break in the grooves weakened the tracks and caused serious problems: damage to the tracks during transportation was almost inevitable. Furthermore, manufacturer pre-processing can only be performed on new tracks and has to be planned well in advance.
For HANNING & KAHL, this meant: if the track does not come to the mill, the mill must come to the track. Thus we developed a portable mill which two people can handle without heavy equipment. It was important to not additionally weaken the tracks with attachment bores. As the track covering has to be removed in order to install the wheel detectors for axle counting, it must be possible to use the machine on exposed track.
Precise vertical milling machine
The result is a vertical milling machine which is mounted on a crosstable attachment (coordinate table) with X and Y axes. This table is attached to the foot of the rail with a clamping device. Via the X and Y axes, the milling machine can now be moved in the necessary directions to the track. Should individual trains have to cross in an emergency while processing, the milling machine can be easily removed from the crosstable attachment. The crosstable attachment remains on the track; it can be driven over as it does not protrude beyond the upper edge of the track. The milling machine can be mounted again in a few easy steps, and processing can be continued immediately with high repeat accuracy.
Detailed procedure for wheel detectors
So as not to remove too much material, the previously traced cut-out is pre-cut with the angle grinder leaving a generous amount of material on the silhouette of the cut-out. The crosstable attachment is mounted on the track und aligned. Then the milling machine is mounted on the crosstable attachment in a few simple steps.
On account of the weight, it takes two people to mount the crosstable attachment on the track and to attach the milling machine. Otherwise all other steps in making a cut-out can be performed by one person. The final silhouette of the cut-out complete with round corners is milled. Finally, a recess is milled on the lower side of the head of the track where the wheel detector can later be inserted a few millimetres underneath the head of the track. From tracing the cut-out to removing the milling machine and the crosstable attachment, the procedure only takes a few hours.