Abstract: A guide rail 4 is used for movably mounting a coal hewing machine on a chain scraper conveyor 3. The hewing machine has a guide shoe 26 guided by the guide rail 4 and a chain wheel. The conveyor 3 has a conveyor channel 2 and, on the filling side, a mounting plate 1 for the guide rail 4. The guide rail 4 defines a chain passage 19 for a chain 20. The guide rail 4 also defines, in its roof side, an engagement groove 17 for the chain wheel and, in its floor side, openings 18 for the discharge of material. The chain 20 comprises long horizontal members 22 and short vertical members 21. The guide rail 4 is of box-shaped configuration and substantially rectangular cross-section. All four sides of the guide rail 4 are engaged by the guide shoe 26. On the filling side, the guide rail 4 has an upper portion in the form of an overhead bar 13 which is screwed to the lower portion 12. The vertical members 21 of the chain 20 project into the engagement groove 17.