A Cert-1/2/3/4 in Transport and Logistics (Rail Operations) is transferrable as that's a nationally-recognised qualification under the TLI competency matrix and is actually a mandatory requirement now for individual accreditation as a rail safety worker under the national rail safety law.
QLD has different SARC (Safely Access Rail Corridor) requirements due to the system(s) of safeworking used in QLD outside of the small part of standard gauge in the Defined Interstate Rail Network being different.
Plus the locomotives and rollingstock are different, and QLD locos have driving controls on the right side of the cab (like the USA/Canada and the Pilbara iron ore lines).
Only new people to the industry who've come through the ranks within the last 5 to 10 yrs have Cert-3 or 4 quals for rail. Most people who've been in the industry longer don't, which is an impediment to accurate RPL'ing but still doesn't stop people already in the industry from going after jobs that specify a Cert-4 is required.
Most rail companies will not bother with the time/expense of putting existing qualified staff through a Cert-3 or 4 process, but I imagine that eventually it'll be required. Currently, newer staff get those quals and in terms of qual portability actually have more demonstrable 'paper' quals than older more experienced staff that don't. Little bit of irony.