The standard deals with so-called "in-plant milk-run systems", which are used as internal transport systems. It is an in-house transport system, which moves bundled units in transport (as a train). It usually consists of a tractor with several trailers and is based on a transport concept in a plant, where suppling- and/or disposal-points are situated along (one or more) defined routes. The route consists of sources and sinks as stops on the route (e.g. an assembly line). Different requirements of application must be met and are explained in the standard, for example: restriction on horizontal transports and the avoidance of provision/collection of material in/from dead ends (with milk-run-system-trains generally no reversing transport is possible); selection of tractors and trailers (see VDI 5586 Part 1); trailer loads (cf. VDI 3973); curve radii, etc.; path widths for the factory layout to check whether a milk-train-use is in principle possible. Small curve radii need as compact and manoeuvrable tractors and small track deviation of the trailer to avoid collisions with persons or objects. The width of tracks has to be sufficient to pass the holding train during loading/unloading with other means of transportation (otherwise congestion and delays). Support and hitching loads of tractor and trailer must not be exceeded individually and in association (maximum carrier weights, steering system or floor covering, and manual handling). The standard contains the description of the characteristics of which can be derived the appropriate applications for milk-train-runs. The advantage of milk-trains is, for example, in the saving of transport routes through bundling (i.e., it is useful in many stops and providing great distances).