A work machine including a machine base mounted movably over an undercarriage, and a hydraulic arrangement which includes a first cylinder configured for operating a working blade of the work machine, a second cylinder configured to vary the width of the undercarriage, a source of fluid at high pressure which is fluidly connected to the first and second cylinders and which is housed in the machine base, and a selection valve which is fluidly interposed between the source and at least one of the first and second cylinders. The valve is housed in the undercarriage.