sounds like there are alot of cost cutting with the train tracks when there are huge corruption...
referencing from Ash007's info, it sounds likely that the train track could be a cause of the accident.
as the derailment seems to be in between, the first carriage could skim through, the 2nd carriage could go off, and drag the rest of the 3 carriages down.
Nothing to do with the rails, it was a headon collision between an idle train and a moving train... software error is the propable cause.