The SX carriage stainless steel bodyshells were constructed by Commonwealth Engineering, Granville with the fitout undertaken at Rocklea in 1961/62.
[2] Initially hauled by steam and later diesel locomotives, provision was made for their conversion to electric multiple units once the network was electrified.
[4][5] Others were exported to the Auckland Regional Council,[6] Ferrocarril de Antofagasta a Bolivia and State Railway of Thailand.
The six carriages in MAXX livery were stored in Taumarunui in the central North Island until sold for a dollar each to the Railway Enthusiasts Society.
[8] There was no further interest in the remaining five, so they were advertised on auction site TradeMe and were sold to private owners around New Zealand with bogies in March 2021 and were removed from Taumarunui on 17 June 2021.