Guide rail, in particular for a transport device or stretching unit, having the following features: - a cooling device in the form of at least one cooling duct (K1, K2, K3) which can be flowed through by a coolant is provided for the guide and/or carrier rail, - the cooling device is constructed in such a way a) that the at least one cooling duct (K1, K2) comprises a plurality of transverse holes (154; 154a-154d), which extend oblique to the longitudinal direction of the guide and/or carrier rail and which are alternately formed at different angles of inclination (α, β) to the longitudinal direction of the guide and/or carrier rail in such a way that in each case at least two successive transverse holes (154; 154a-154d) intersect in a penetration region (DX1 a, DX1 b; DX2a, DX2b) to form a continuous duct (K1, K2), and/or b) that the guide and/or carrier rail comprises at least two half shells or halves (15.1, 15.2), between which a flexible pipe is arranged sandwiched to form the at least one cooling duct (K1, K2), and/or c) that the at least one cooling duct is arranged outside the guide and/or carrier rail extending parallel thereto, and that a multiplicity of holes are formed in the guide rail, which are positioned offset in the longitudinal direction of the guide and/or carrier rail and orientated transverse and preferably perpendicular thereto, and into which heat lines and/or heat pipes are inserted, which protrude beyond the guide and/or carrier rail and are thermally conductively linked to the at least one cooling duct extending outside the guide and/or carrier rail. - a cooling device in the form of at least one cooling duct (K1, K2, K3) which can be flowed through by a coolant is provided for the guide and/or carrier rail, - the cooling device is constructed in such a way a) that the at least one cooling duct (K1, K2) comprises a plurality of transverse holes (154; 154a-154d), which extend oblique to the longitudinal direction of the guide and/or carrier rail and which are alternately formed at different angles of inclination (α, β) to the longitudinal direction of the guide and/or carrier rail in such a way that in each case at least two successive transverse holes (154; 154a-154d) intersect in a penetration region (DX1 a, DX1 b; DX2a, DX2b) to form a continuous duct (K1, K2), and/or b) that the guide and/or carrier rail comprises at least two half shells or halves (15.1, 15.2), between which a flexible pipe is arranged sandwiched to form the at least one cooling duct (K1, K2), and/or c) that the at least one cooling duct is arranged outside the guide and/or carrier rail extending parallel thereto, and that a multiplicity of holes are formed in the guide rail, which are positioned offset in the longitudinal direction of the guide and/or carrier rail and orientated transverse and preferably perpendicular thereto, and into which heat lines and/or heat pipes are inserted, which protrude beyond the guide and/or carrier rail and are thermally conductively linked to the at least one cooling duct extending outside the guide and/or carrier rail. a) that the at least one cooling duct (K1, K2) comprises a plurality of transverse holes (154; 154a-154d), which extend oblique to the longitudinal direction of the guide and/or carrier rail and which are alternately formed at different angles of inclination (α, β) to the longitudinal direction of the guide and/or carrier rail in such a way that in each case at least two successive transverse holes (154; 154a-154d) intersect in a penetration region (DX1 a, DX1 b; DX2a, DX2b) to form a continuous duct (K1, K2), and/or b) that the guide and/or carrier rail comprises at least two half shells or halves (15.1, 15.2), between which a flexible pipe is arranged sandwiched to form the at least one cooling duct (K1, K2), and/or c) that the at least one cooling duct is arranged outside the guide and/or carrier rail extending parallel thereto, and that a multiplicity of holes are formed in the guide rail, which are positioned offset in the longitudinal direction of the guide and/or carrier rail and orientated transverse and preferably perpendicular thereto, and into which heat lines and/or heat pipes are inserted, which protrude beyond the guide and/or carrier rail and are thermally conductively linked to the at least one cooling duct extending outside the guide and/or carrier rail.