A trenching apparatus, includes a body moveable on the ground surface, a ground engagement boom associated with the body, the boom being movable when engaged with the ground to form a trench; a lifting system arranged to control and configure the ground engagement boom so as to enter the ground; in which the ground engaging boom is an endless chain ground-engaging boom, including a main body and a chain tensioner coupled to the main body at or close to the upper end thereof.

A link for an excavating chain for a ballast excavating device below a railroad track, the link comprising a body extending longitudinally between a front end and a rear end and being crossed by at least one front through-hole and a rear through-hole configured to receive hinge means with an adjacent link of the chain, the front and rear through-holes extending along axes parallel to each other and contained in a reference plane of the body, the link further comprising, on an inner side of the body with respect to the reference plane opposite to the outer side, a concave guide surface extending over an envelope having an axis generator parallel to the axes of the link joints, the guide surface being configured to at least locally match a curvature of a return member of the excavating device.

The present disclosure provides a dredging device including a body. The body includes a salvaging device salvaging sludge, a crushing device crushing the sludge, a sludge discharging device discharging the sludge, and an adjustiug device adjusting a height of the dredging device and moving. The salvaging device includes a driving wheel, a driven wheel, a transmission belt, salvaging hoppers. The dredging device further includes a second motor, crushing wheels, and a baffle. The second motor is turned on to drive a first gear to engage with second gears, so that rotating shafts drive the crushing wheels to crush sludge and larger stones. The baffle blocks an upper portion of the crushing wheels, which avoids the sludge splashing on a worker.