A properly driven, well maintained vehicle should never have issues braking on such a road. Poor or non existant maintenence is a known problem with these tour operators. My money is on that being the cause of the incident.
As for the dangling leg ban, Passengers on trains operated by the PBR are under the care of the PBR. not the care of every single motorist in the area. The PBR can not control every vehicle that interfaces with their railway, all they can do is put in the appropriate safe guards. On the sort of roads that cross that track, with their trains having a maximum permissable speed of no more than 40km/h I can't see that boom gates are necessery, If there had of been operating boom gates on this occasion, they wouldn't have stopped the bus hitting the train. Booms are not necessary.
Seat Belts, that is just ludicrous.
Remember, nobody on the train was injured. It's hard to see how that outcome would have been the same if somebodies legs had of been pinned between the carriage and the bus.
Despite everything, I expect the leg dangling will return after the investigation is complete.