drive over the denpr h2h question

[Ivan]

I'm playing the smolensk h2h scenario 'drive over the dnepr'. I was planning on getting my 172nd division HQ across the river into hex 28,32. For some reason it's not allowing it to cross in T mode with full movement points. I know this hex contains swamp but does it not also contain a railway line?
I tested this on the non h2h scenario and it seems to allow motorised units across but not in my h2h version. Anyone know if this is an error, a bug or deliberate? Perhaps I'm missing something. It will mean I have to lose my HQ as no other crossings are left. Such is life I guess!