When Cath disconnects the two cars (while talking to August Schmidt), he uses a crowbar and drops it as the couplers release. In the next shot the crowbar is back in his hands.
In the end credits, the music by Cesar Franck is said to be the Sonata in G. Not only is it, in fact, the Sonata in A, but Franck has never written a sonata for violin and piano in G.