Abstract: The present invention relates to water-resistant, thermoplastic starch materials processable into environmentally safe, thermoplastically produced products and cast sheets, which consist of starch acyl compounds, obtainable from high amylose starches and the derivatives thereof and being sparingly soluble in water, and of plasticizers which like ethyl citrate, glycerol acetate and lactic acid ester have a gelatinizing effect and preferably a dissolution property resulting in brilliant transparence and, as can be proved, are biodegradable.

Abstract: Water-resistant, thermoplastic starch materials which are processable into environmentally safe, thermoplastically produced products and cast sheets. They consist of starch acyl compounds, obtainable from high amylose starches and their derivatives (being sparingly soluble in water), and of plasticizers (like citric acid ethyl ester, glycerol acetate and lactic acid ester), which have a gelatinizing effect, and preferably, a dissolution property resulting in brilliant transparence and, as can be proved, are biodegradable.

Abstract: This machine comprises at least one grinding unit mounted to a grinding base. Each unit comprises a frame secured to the grinding base. The grinding wheel is driven by an electric motor, suspended from the frame by means of four rocker arms constituting two parallel-motion suspension systems. The lower rocker arms are levers of the first order and the grinding pressure is applied for one of the rocker arms by the piston rod of a hydraulic cylinder rigid with the frame and adapted to position the grinding wheel in relation to the rail, and for the other rocker arm by the piston rod of a pneumatic cylinder also rigid with the frame. This pneumatic cylinder determines the operating pressure of the grinding wheel on the rail. The operative face of the grinding wheel is parallel to the plane of the theoretical tangent to the rail profile. A right-angled lever is pivoted to a projection of the frame and provided at one end with a stud facing the grinding wheel.