The tamping tine becomes a measuring instrument, and the working parameters are adjusted based on its findings. This makes it possible to improve the quality of the entire infrastructure system while reducing costs.

Priv. Doz. Dipl.-Ing Dr. Fritz Kopf
Univ.-Prof. Dipl.-Ing. Dr. Dietmar Adam, TU Wien

Best results for linear tamping are given by simulation with values - amplitude = 5 deg, frequency = 35 Hz, [...]
At higher frequencies, liquefaction of ballast occurs resulting in poor compaction and faster deterioration of ballast.

Nilesh M. Dama, Virginia Tech

The ballast bed requires optimum compaction in order to ensure a stable and high-quality track geometry for achieving a safe operating condition of the superstructure.

Ballast resistance during compaction

Extensive testing has shown that ballast can be compacted sustainably at 35 Hz. At lower frequencies, a sustainable correction of the track geometry is not possible. Higher frequencies cause the ballast to flow. That makes it difficult to produce the desired track geometry.

Effect of frequency and amplitude on the stabilization of track ballast

During the tamping process, the tamping tines penetrate the ballast bed from above. Thanks to the squeezing movement, the cavity under the sleeper is filled with ballast and then compacted. Three parameters are decisive here:

  1. Constant tamping pressure
  2. An optimum frequency of 35 Hz 
  3. A stable amplitude of 4 to 5 mm thanks to a reliable design

New sensor technology - new opportunities

When comparing measurements conducted in clean and fouled ballast, the following behaviour can be observed: given the same pressure level, tamping of fouled ballast significantly increases the dynamic tamping force, reaching higher force values.

Clean ballast
Fouled ballast

New measuring and analysis method

Thanks to a brand new measuring and analysis method, it is now possible for the first time to observe the movement behaviour of ballast throughout the entire tamping process. In addition, the method provides an unprecedented level of detailed insight into the ballast condition. The tamping tine is particularly important here: the new method allows for the development of the tamping tine from a working tool to a measuring instrument.

Plasser TampingAssistant

Plasser & Theurer’s turnout tamping assistance system, “Plasser TampingAssistant”, supports the operator in using the machine’s operational systems and contributes significantly to the automation of tamping machines.

More than
patents in the field of tamping and ballast compaction technology
More than
active patents