[ Potsdam ], [ Mannheim ] --> { end: back,0; } [ Weimar ]
# [ Weimar ] --> { start: front,0; } [ Finsterwalde ], [ Aschersleben ]
[ Potsdam ], [ Mannheim ] --> { end: back,0; } [ Weimar ]
# [ Weimar ] --> { start: front,0; } [ Finsterwalde ], [ Aschersleben ]