Better still, if the Eyre Highway closes, can't the State or Federal government get PacNat or SCT to put on extra trains at say Kalgoorlie and Port Augusta to take cars and trucks across the Nullabor using car car carriers and flatbeds (and sit up class)?
How would those operators do that? They aren't government rail operators who can afford to have fleets of wagons, locos and staff sitting around doing nothing most of the time because Someone Else pays the bills.
In general, it's actually far more likely that the railway would be the mode closed for periods of multiple days at a time. If the rail operators are to invest in improving the resilience of their services, the best method of doing it would be via a small fleet of trucks which could take high priority freight off a stranded train (priority determined by an auction) and get it moving in the right direction without waiting for the line to reopen.
This would be cheeper should it ever be needed.
Eyre Highway closure for such a long period of time is unusual. When was it last closed like this? Maybe due to damage from flooding?
Indeed it is unusual. That's why it's newsworthy.
It's certainly unusual enough that the best method of dealing with it is, well, just dealing with it.