Abstract: A mobile track working machine arranged for intermittent advancement along the track comprises a drive, a brake for braking the driven wheels at respective working sites between the intermittent advancement of the machine, a speedometer generating a signal indicating the speed of advancement and a device generating a signal indicating the peripheral speed of the driven wheels. A fully electronically operated control arrangement for avoiding spinning of the driven wheels at the start of the advancement of the machine and locking of the wheels at braking includes a circuit having an input receiving the signals and an output connected to the drive and brake for constantly maintaining the nominal desired value of the drive and brake moments and for reducing the traction and brake forces in dependence on any drive or brake slippage.

Abstract: In a mobile track leveling and tamping machine, a hydraulic control system operates a drive for reciprocating vibratory tamping tools. The system includes a hydraulic fluid containing receptacle, a three-way proportional electro-hydraulic valve having an outlet connected to one cylinder chamber of the drive and another outlet connected to the hydraulic fluid containing receptacle, a hydraulic pressure regulator steplessly adjustable to a desired maximum tamping pressure exerted by reciprocation of the tools, a differential element having two inputs and an output connected to the valve, and a threshold value stage connected between the transmitter and one of the differential element inputs, the other input being connected to the regulator and a third outlet of the valve being connected to the other cylinder chamber whereby the hydraulic pressure therein is controlled in response to the threshold value.

Abstract: A control arrangement for operating the hydraulic drive and for monitoring the vertical movement and a corresponding immersion depth of the tamping tools in the ballast of a tamping unit includes a hydraulic fluid control circuit connected to the hydraulic drive for the unit, a control valve in the control circuit, the valve being capable of steplessly adjusting hydraulic fluid flow to the drive, and a control connected to the valve for adjustment thereof. The control has a first signal transmitter providing a control signal indicating the actual vertical position of the tamping unit and a second signal transmitter providing another control signal indicating a desired immersion depth of the tamping tools in the ballast.