Abstract: A ballast plow (1) comprises a machine frame (6) supported on on-track undercarriages (2), with which is associated a center plow (5) which is vertically adjustable by means of drives and on each longitudinal side of the machine a vertically adjustable shoulder plow (8) having a plow blade (20) which may be brought into contact with ballast. The shoulder plow is provided with an articulation point (13) and a telescopically extendable carrier frame (12) extending perpendicularly to the longitudinal direction of the machine. The articulation point (13) is situated in each case--viewed in the transverse direction of the machine--on the longitudinal side of the machine which is further away from the associated plow blade (20) of the shoulder plow (8). The plow blade (20) is mounted for pivoting about an axis (21) extending in the longitudinal direction of the machine and is connected to a shoulder angle adjustment drive (15).