Abstract: A ballast excavation chain arrangement includes a polygonal chain guide and an endless ballast excavation link chain supported therein. The lower portions of two longitudinally extending guide sections are connected to respective ends of a transversely extending guide section and the latter guide section and a portion of the link chain is mounted for extension transversely of, and below, the track for excavating ballast. Hydraulic drives are provided for laterally adjusting at least the lower portions of the longitudinally extending guide sections for selectively extending the chain guide to the right and to the left of the track.