I'm not familiar with Finnish Railways but it may be that the coaches where fitted with US style couplings... Some in Europe are. But even if this is the case as the train was being propelled it is possible that if there was a slight grade in the yard maybe someone forgot to check the coupling-the trian could have been leaning on th eproperly secured part until moved.
G
Gavin
Linslade
Bedfordshire
UK
Garratt Locomotives
[
www.beyergarrattlocos.co.uk]