After World War II ended the New South Wales Government Railways embarked on a program of modernisation using aluminium construction skills developed to support wartime demand for aircraft components.
Class leader set 621/721 commenced trials on 8 August 1961 with a return run to Penrith. Following a second trial to Katoomba two days later 621/721 was delivered to Newcastle on 21 August 1961. The unit entered operational service on 4 September 1961 and from this time became affectionately known as the Red Rattler.
621 was rostered to perform the last regular 620/720 service to Dungog mismatched with trailer car 725 on 2 June 2007. On October 29 of the same year a special RailCorp run to Paterson was organised with invited guests, to farewell the sets and see 621 reunited with 721.
During their service life 621/ 721 spent all of their time on Hunter services. It is therefore fitting that this unit is preserved in the Hunter region and has seen a number heritage services since joining the Rail Motor Society’s fleet.
The Rail Motor Society volunteers dedicated many hours into the restoration of the two car unit which has been repainted in the original Indian Red livery with the traditional “whiskers” lining. Additional works included the repair of a number of minor areas of corrosion and the replacement of timber flooring around the entrance door areas of 621.
In January 2010 621/721 took to the tracks beautifully restored and to the delight of passengers and rail enthusiasts.
The Red Rattler proudly took part in the 30th Anniversary of Hunter Valley Steamfest in 2016.