The present disclosure generally relates to a railroad track ballast tamping vehicle and associated methods of use, wherein the vehicle comprises: a rigid frame; a variable-displacement servo-pump operatively coupled to the vehicle; at least one linear hydraulic actuator operatively coupled to the frame at a proximal end of the at least one linear hydraulic actuator and comprising: at least one internal cavity for receiving hydraulic fluid from the variable-displacement servo-pump via a hydraulic hose; and an actuator rod passing through a first internal cavity and a second internal cavity of the at least one linear hydraulic actuator; and a tamping tool operatively coupled to a distal end of the at least one linear hydraulic actuator. A tamping pad associated with the tamping tool may be lowered into ballast underlying railroad tracks and between railroad track ties for performing ballast tamping operations.

A piston unit of a working cylinder includes a piston and a piston rod. The piston has an axial bore hole formed therein. The piston rod is received in the axial bore hole. The piston rod and the piston are connected by a material-bond by a circumferential laser ring weld seam. The laser ring weld seam defines a pressure medium-tight sealing plane.

A hydraulic control block for controlling a supply of pressurizing medium to an electrohydraulic or servo hydraulic axle includes a plurality of internally situated hydraulic interfaces configured to fluidically connect at least one of a source of pressurizing medium and a pressurizing medium sink of the axle to any hydraulic cylinder selected from a group of hydraulic cylinders of different structural forms, wherein the internally situated hydraulic interfaces are configured to selectively supply pressurizing medium to the selected hydraulic cylinder. The control block further includes an insert part configured as a function of the structural form of the selected hydraulic cylinder such that each of the plurality of internally situated hydraulic interfaces is one of tapped and blocked for the purpose of the fluidic connection.

A series train of symmetrical dual rod-end double-action hydraulic cylinders with a cross sectional area in a series of powers of 2. The cylinders have corresponding computer controlled valves. The cylinders are switchable into three states. One state of shortcutting 2 fluid ports, another state of driving towards each opposite direction of reciprocation and the third state of idling. In the cylinder train all same polarity ports of the valve assembly are connected by hoses or pipes to align towards the same orientation to enable synchronous reciprocal motion and train power output.

A method for controlling a control surface multirod actuator arrangement and the arrangement including: a first and a second multirod actuator configured to move or clamp around a first set of piston rods; a third multirod actuator configured to move or clamp around a second set of piston rods; a control unit configured to control motion of the first set of piston rods in a first motion mode and to control motion of the second set of piston rods in a second motion mode. Steps are moving at least one piston rod of first set of piston rods and/or clamping in parked position at least one piston rod of the second set of piston rods.

A hydraulic system for a vehicle includes a hydraulic monitoring control unit configured to receive an operational signal from a sub-system of the vehicle and control flow of hydraulic fluid to actuators of components based on the operational signal. The hydraulic monitoring control unit is configured to bypass the flow of the hydraulic fluid in relation to a subset of the actuators in response to the operational signal indicating an altered operational state of the sub-system.

An electro-hydrostatic actuation system and a method for driving a hydraulic actuator, e.g. a hydraulic cylinder, are described, wherein the system comprising a leakage branch, and wherein preferably an additional pump is arranged. The system further comprises a source for providing hydraulic liquid; a high-pressure circuit to direct the hydraulic liquid to a hydraulic actuator, such as e.g. a hydraulic cylinder; a low-pressure circuit having several branches; a main pump for hydraulic liquid arranged in the high-pressure circuit, comprising a housing having a high-pressure section and a low-pressure section, separated by gap sealings, wherein the high-pressure section comprises a first outlet and a second outlet to provide the hydraulic liquid flow in the high-pressure circuit; and wherein the low- pressure section comprises a leakage outlet; an electric motor driving the main pump.

A system and method for detecting the functional state of a piloted or direct-operated isolation valve in a hydraulic circuit is presented. In some examples the hydraulic circuit is a steering circuit and the isolation valve provides selective isolation between a hydraulic actuator and one or more metering valves. In some examples, the isolation valve assembly is movable between a first position, in which fluid flow between the metering valve and the actuator is enabled, and a second position, in which fluid flow between the metering valve and the actuator is blocked. When the isolation valve assembly is moved to one of the first and second positions, an inlet port and a pressure sensing port of the isolation valve assembly are placed in fluid communication with each other. When the isolation valve assembly is moved to the other of the first or second position, a second inlet port and the pressure sensing port are placed in fluid communication.

A fail-safe actuation system comprising an actuator having first and second chambers, a working circuit with a motor/pump device configured to actuate the actuator in an operative state, and a safety circuit configured to move the actuator into the safety position in a failure state, the safety circuit having a tank that holds pressurized fluid and that, in the failure state, is automatically connected to the first chamber via a switching valve, and having a drain valve that, in the failure state, is moved into a through-flow position in order to drain fluid out of the second chamber, the safety circuit configured such that, in the operative state, an inflow into the actuator—in a manner that is decoupled from the tank—is established by the working circuit, and, in the failure state, an inflow from the tank into the first chamber—in a manner that is completely decoupled from the working circuit—is created by the safety circuit, whereby a short-circuit fluid connection is provided between the first and second chambers that, in the failure state, is through-connected in order to generate a short-circuit flow between the first and second chambers.

A method is provided for detecting a reciprocal position between a cylinder and a piston of a piston-cylinder unit of a vehicle. The method includes measuring, by means of an optical sensor, a value of an indicative parameter of a color of a reference mark positioned on a portion of the piston. The method also includes comparing the measured value with at least a predetermined threshold value thereof different to a minimum detected threshold of the indicative parameter by the optical sensor; and

emitting an alarm signal perceptible by a driver of a vehicle if the measured value is comprised between the threshold value and the minimum value.