A system comprising first and second coupling units (612; 2200, 613; 2202), wherein the first coupling unit (612; 2200) comprises: a first device for mating with a corresponding second device of the second coupling unit (613; 2202); a number of first coupling elements comprising at least one of a first power coupling element (618; 2206), a first air coupling element (620; 2208), a first hydraulic coupling element, a first communications coupling element (624; 2216), or a first water coupling element; and a first alignment system for aligning the first device with the corresponding second device and the number of first coupling elements with a corresponding number of second coupling elements, wherein the first alignment system comprises a guidance fork (656; 2232) for receiving a roller (660; 2234), wherein the second coupling unit (613; 2202) comprises: the second device; the number of second coupling elements, wherein the second coupling elements comprise at least one of a second power coupling element (630; 2220), a second air coupling element (632; 2222), a second hydraulic coupling element, a second communications coupling element (636; 2224), or a second water coupling element; and a second alignment system for aligning the second device with the first device and the second number of coupling elements with a corresponding number of coupling elements, wherein the second alignment system comprises the roller (660; 2234), wherein the first device is a first quick-change device (625, 2204) and the second device is a second quick-change device (628, 2218), wherein the first quick-change device (625, 2204) is configured to mate with the second quick-change device (628, 2218). a first device for mating with a corresponding second device of the second coupling unit (613; 2202); a number of first coupling elements comprising at least one of a first power coupling element (618; 2206), a first air coupling element (620; 2208), a first hydraulic coupling element, a first communications coupling element (624; 2216), or a first water coupling element; and a first alignment system for aligning the first device with the corresponding second device and the number of first coupling elements with a corresponding number of second coupling elements, wherein the first alignment system comprises a guidance fork (656; 2232) for receiving a roller (660; 2234), the second device; the number of second coupling elements, wherein the second coupling elements comprise at least one of a second power coupling element (630; 2220), a second air coupling element (632; 2222), a second hydraulic coupling element, a second communications coupling element (636; 2224), or a second water coupling element; and a second alignment system for aligning the second device with the first device and the second number of coupling elements with a corresponding number of coupling elements, wherein the second alignment system comprises the roller (660; 2234), wherein the first device is a first quick-change device (625, 2204) and the second device is a second quick-change device (628, 2218), wherein the first quick-change device (625, 2204) is configured to mate with the second quick-change device (628, 2218).