the second is still on a straight track fig1 shows a different embodiment of such a coupling which can be rotated about the longitudinal axis the coupling heads 3211 and 3611 shown there once again with plug in prolongations 31 are provided in each case with an end plate 40 or 41 of which the former has two head pins 43 which grip behind the circular slots 44 of the latter threading expansions 45 for threading being provided at the ends of the circular slots 44 the threading expansions are provided offset in such a way that the threading can take place only by tilting the vehicle super structures about extremely opposite positions to one another such extreme opposite positions cannot occur in practice even in tight s curves so that automatic uncoupling cannot take place finally in fig1 a tight coupling is shown diagrammatically which is suitable particularly for the self aligning superstructures of the present invention but also entails advantages for other vehicles without self aligning superstructures for this embodiment the coupling shaft 47 is hinged pivotably about the axis 48 at an only diagrammatically indicated carriage frame 6 of an otherwise not shown carriage the bridge shaped component 49 which can be locked with the carriage frame 6 by recesses in the latter that are not shown serving for fixing to the carriage frame the coupling shaft 47 is supported at a lug 50 with.