Abstract: The invention relates to a method for tamping sleepers of a track panel, supported in a ballast bed, by means of a tamping unit, comprising two tamping tools opposite one another which, during tamping of the respective sleeper, are lowered into the ballast bed with vibrations being applied, and are moved towards each other with a squeezing movement while the track panel is held in a raised position. In this, an evaluation device is used to monitor a squeezing speed of at least one tamping tool, with a current value of the squeezing speed being compared with a limit value when a predefined squeezing time or a predefined squeezing distance is reached, and with a notification signal indicating whether the current value is above the limit value. This may indicate that a void located below the sleeper has not yet been sufficiently filled.

Abstract: An exhaust turbocharger includes an exhaust control device provided with an exhaust flap for adjusting an exhaust gas flow flowing through a turbine stage of the exhaust turbocharger during the operation thereof, a control gear coupled to the exhaust flap, and a servomotor via which the exhaust flap can be moved in a regulated and/or controlled manner by operation of the control gear at least between a closing position, in which the exhaust flap closes an exhaust gas opening in a turbocharger housing of the turbocharger, through which exhaust gas flows during the operation of the exhaust turbocharger, and at least one other position in which the exhaust flap allows exhaust gas to flow through the exhaust gas opening. The control gear is a self-locking gear via which the exhaust flap can be prestressed in the closing position thereof in relation to the turbocharger housing.

Abstract: A method for controlling/regulating a rotatory drive of a working unit of a track maintenance machine includes using a sensor to record a measurement parameter with an approximately periodic history function derived from a rotation of the drive. A frequency or period duration of the history function is determined with an evaluation device, and the frequency or period duration is compared with a target parameter for stipulating a control signal. A number of time-discrete measurement values is formed for the measurement parameter and an auto-correlation of these measurement values is carried out by a calculation unit for determining the frequency or the period duration. As compared to a conventional method with zero stage recording, a precise recording of frequency changes is therefore also possible between two zero stages. A device for carrying out the method is also provided.

Abstract: A method for compacting a ballast bed, on which railroad ties and track rails secured thereto are supported, uses a work assembly which is arranged on a track construction machine that can be moved on the track. During a compaction process, a signal is detected and a characteristic variable is derived therefrom by an analysis device in order to evaluate the quality of the ballast bed. The work assembly contains an electric drive, by which the compaction process is at least partly carried out. At least one operating variable of the electric drive is supplied to the analysis device, and a ballast bed characteristic variable is derived from the operating variable by the analysis device.

Abstract: An exhaust turbocharger includes an exhaust control device provided with an exhaust flap for adjusting an exhaust gas flow flowing through a turbine stage of the exhaust turbocharger during the operation thereof, a control gear coupled to the exhaust flap, and a servomotor via which the exhaust flap can be moved in a regulated and/or controlled manner by operation of the control gear at least between a closing position, in which the exhaust flap closes an exhaust gas opening in a turbocharger housing of the turbocharger, through which exhaust gas flows during the operation of the exhaust turbocharger, and at least one other position in which the exhaust flap allows exhaust gas to flow through the exhaust gas opening. The control gear is a self-locking gear via which the exhaust flap can be prestressed in the closing position thereof in relation to the turbocharger housing.