The key to fault correction

Every tamping machine needs integrated measuring technology to enable the correction of level and line faults in tracks and turnouts. Therefore, the standard equipment for all of our tamping machines comprises measuring systems for correcting track geometry faults in longitudinal level, cross level and longitudinal alignment: the proportional parallel levelling system and the single-chord lining measuring system.

The sturdy mechanical design, the large measuring wheels and the comfortable operating concept ensure highest precision. Vegetation or vibrations and dust caused during operation hardly affect the accuracy of the measurements. In addition, the systems are easy to inspect and to service. On all tamping machines, the Win-ALC automatic guiding computer performs the comprehensive guidance of the levelling and lining systems during work (see page 24).

Inside the machines, steel chords are used as reference bases. Outside the machines, laser is used as measuring base.


In conjunction with the lifting unit of the tamping machine, the system is used to measure and correct the longitudinal and cross levels of the track. Proportional to the lifting value, electronic signals are produced via transducers for automatic control of the track lifting hydraulics.

Two methods of work are available: the compensation method and the precision method. An optical radio direction-finder or a laser direction-finding unit can be used for optimum correction of long wave faults in the longitudinal level.


This recognises existing alignment faults in the track geometry and reduces or eliminates them using the tamping machine’s hydraulic lining unit. Depending on the operating requirements, two methods of work can be selected: the 4-point method and the 3-point method. The latter is particularly suited for the precision method.

The sturdy mechanical design of the measuring technology ensures precision despite harsh conditions on track.


For the precise treatment of tangent track, the elimination of long wave faults or lifting and lining using fixed points, the front reference point of the measuring systems must move along an absolutely straight line. Additional optical systems or laser systems extend the machine’s measuring base for levelling and lining.

The laser measuring systems consist of a laser receiver camera mounted on the tamping machine’s front tensioning trolley and a laser transmitter positioned at a suitable distance from the machine. The point-like laser beam records and corrects the longitudinal level and alignment at the same time.

Combined longitudinal level and alignment laser

During track tamping, the combined longitudinal level and alignment laser guides the tamping machine according to the precision method. Using this method, the laser beam is displayed on the laser receiver camera (at the tamping machine) and analysed according to its position.

The combined levelling and alignment laser also allows producing a particularly accurate turnout geometry. In doing so, the ideal geometric position of the turnout (in the through rail) is recorded along the laser reference line.

CAL curve laser system

The CAL offers all laser functions available for straight-line track also for turnouts. It allows applying the precision method for tracks as well as turnouts. This enables working on all known types of track geometry. In particular, it is used for the first tamping passes after track renewal and for secondary lines. Moreover, the curve laser can be used in the diverging rail in turnouts and in curved turnouts.

Optical direction-finder with radio remote control

The optical direction finder is a simpler alternative. It consists of an optical sighting device and levelling boards at the front end of the machine. The optical sighting device is positioned at a fixed point at 100 m to 150 m from the machine, aiming at the sighting markers. Using the radio remote control, the levelling device and the lining chord are adjusted until the cross hair of the telescope and the sighting markers on the levelling board match.