Abstract: A tribological system may include a valve seat ring composed of a sintered material and a valve having a surface at least in a seat region that may be at least one of (i) untreated, (ii) hardened, and (iii) plated. The sintered material may be a pressed and sintered powder mixture having a composition that may include (i) 5 to 45 wt % of at least one Fe-based hard phase, (ii) 0 to 2 wt % of each of graphite particles, MnS powder, MoS2 powder, and FeP powder, (iii) 0 to 7 wt % copper powder and 0 to 4 wt % Co powder, (iv) 0.1 to 1.0 wt % of a pressing aid, (v) a high-speed steel having a composition including 14-18 wt % Cr, 1.2-1.9 wt % C, 0.1-0.9 wt % Si, 0.5-2.5 wt % of each of V, W, and Mo, and (vi) a balance of Fe and production-related impurities in quantities of <1.5 wt %.

Abstract: A tribological system may include a valve seat ring composed of a sintered material and a valve having a surface at least in a seat region that may be at least one of (i) untreated, (ii) hardened, and (iii) plated. The sintered material may be a pressed and sintered powder mixture having a composition that may include (i) 5 to 45 wt % of at least one Fe-based hard phase, (ii) 0 to 2 wt % of each of graphite particles, MnS powder, MoS2 powder, and FeP powder, (iii) 0 to 7 wt % copper powder and 0 to 4 wt % Co powder, (iv) 0.1 to 1.0 wt % of a pressing aid, (v) a high-speed steel having a composition including 14-18 wt % Cr, 1.2-1.9 wt % C, 0.1-0.9 wt % Si, 0.5-2.5 wt % of each of V, W, and Mo, and (vi) a balance of Fe and production-related impurities in quantities of <1.5 wt %.

Abstract: A tamping tool unit for a ballast tamping machine comprises a pair of reciprocatory tamping tools pivotally supported on axles which are rotatable in eccentric bearing bushings rotatably mounted on the axles. Rotation of the eccentric bearing bushings imparts a compound motion to the tamping tools consisting of a vertical and a horizontal component.