1. can be either A or B. The infinitive, of course,
has no tense marker, so the next train to arrive is either the next
train that was expected to arrive or the next train that did arrive.
2.
is C, to my ear. the next train to have arrived is the next train
that was to have arrived or that was supposed to have arrived or that
was expected to have arrived. This case has a strong
counterfactual feel to it. We're not sure the train has arrived
at all. It was to have arrived, but it didn't.
CJ