In early 1958 an order was placed with Commonwealth Engineering for 10 stainless steel air-conditioned sleeping cars for use on the Brisbane Limited express and between November 1960 and May 1961 these cars entered service.  These cars and the newly allocated RUB sets formed the consist for the Brisbane service, the four rostered sleeping cars being at the Sydney end of the train in both directions.

During this time discussions were also taking place to develop specifications for the carriages to be used on the proposed overnight sleeping express between Sydney and Melbourne, the train to enter service following completion of the new standard gauge line in Victoria.  In May 1960 it was announced that Commonwealth Engineering had won the contract to build 34 cars which would provide for two 14 car sets and 6 spare cars. 

On Thursday 12/04/62 at a formal dinner to officially launch the new service between Sydney and Melbourne, the name of the train was announced  - Southern Aurora.  Over the weekend the two sets were on display at both Sydney and Melbourne before regular revenue services commenced on Monday 16/04/62.

The standard Southern Aurora® set comprised 14 cars – 5 roomette (coded LAN), 4 twinette (NAM), 1 deluxe (DAM) sleeping cars, an RMS dining car, BCS lounge car, MHN brake and PHN power van.  This consist, which had a total weight of 641 tons (655 tonnes), could accommodate 198 passengers.  When introduced the train was rostered to be hauled by two 44 class locomotives in NSW and one S class in Victoria.  As well as a name plate attached to the sides of the Lounge Car, a distinguishing feature of the train was an illuminated Southern Aurora® sign on the trailing end of the set.  The train operated every night from both capital cities and was scheduled to depart at 8pm and arrive the following morning at 9am.

Also at this time, the former broad gauge train Spirit of Progress commenced operating on the new standard gauge to provide a second overnight service between the two cities.  During earlier planning for the train’s conversion to standard gauge it was also decided to provide each set with an NAM twinette sleeper and PHN power van and additional cars were ordered from Commonwealth Engineering in December 1960.

In February 1969 nine people died when the southbound Southern Aurora® was involved in a head on collision with a goods train just to the south of Violet Town in Victoria.  As a result of the collision seven carriages were destroyed.  To replace the lost cars seven Indian-Pacific type carriages were leased from Commonwealth Railways and Railways of Australia until replacement Southern Aurora® type cars were built by Commonwealth Engineering and delivered by late 1970. 

In July 1973 Motorail was introduced on the Southern Aurora®, this service allowing passengers to transport their motor car on a specially provide car carrier wagon attached to the service.  Just prior to departure the car carrier was shunted from the loading point and attached to the front of the train.  To enable the car carrier to be quickly uncoupled from the train following arrival the next morning, the car carrier was shunted to the rear of the train at Albury during the change over of  locomotives at the border station.  With the introduction of Motorail, the illuminated Southern Aurora® sign was no longer used on the train.

In August 1981 the first of the new XPT power and sitting cars were handed over to the State Rail Authority and during September they formed a promotional train that toured the state.  Part of this consist included Southern Aurora® brake van MHN 2364 which had been decorated in a similar paint scheme to that of the XPT stock.  Following the promotional tour, the van had the livery removed at it returned to the Southern Aurora® roster.

Over the years competition resulted in declining patronage on the overnight trains.  Whilst a standard Southern Aurora® set was 14 cars (plus, after 1973, Motorail wagons) softening demand would often see the set varied between this and 10 cars.  On occasions in the later years, consists down to eight cars were also to be seen.  As a consequence of reduced demand and increasing costs the decision was made to amalgamate the Southern Aurora® and Spirit of Progress services and on Saturday 02/08/86 the final departures of both trains occurred. 

On the following night a new service, named the Sydney/Melbourne Express, commenced operation.  With the new service the old Southern Aurora® signs were removed from the Lounge Cars and new name plates fitted, Sydney Express on the east side of the car and Melbourne Express on the west side to coincide with the carriage side on view at the departing terminal.  New graphics and insignias also adorned the Dining car as well as the Lounge Car. 

In February 1990 a number of changes were made to New South Wales operated passenger services.  Part of this included withdrawal of the locomotive hauled Brisbane Limited and Pacific Coast Motorail services, replacing them with XPT sets, and the withdrawal of the Motorail service on the Sydney/Melbourne Express.  By March 1990 the 1975/76 built FAM twinette sleeping cars released from the North Coast services replaced the NAM cars on the Sydney/Melbourne Express.  NSW owned sitting cars from the withdrawn consists also commenced to cross over to the Sydney/Melbourne Express, which then enabled the return over time of the former Spirit of Progress sitting cars to the Victorian broad gauge network.