Built in 1938, Rm 30 was the first of 6 Standard railcars. They were designed with a driving cab at each end and seating in two compartments with a centre toilet. When built Rm30 had seats for 36 passengers in second class and 12 in first class. This was changed later when the first class seats were removed and 16 second class seats fitted in there place. The original Leyland Diesel engines were replaced in the early 1950s with Meadows diesel engines. They are mounted under the driver’s seat at both ends.

Rm 30 had many colour scheme changes over the years, originally being painted silver with a green strip, this was later changed after complaints that the railcars were hard to see at level crossing, forcing New Zealand Railways to paint them all over Red with a grey roof. Later it had silver flashes painted on and the roof colour also changed to silver. The standard railcars were all named after Maori Canoes, Rm30 being named Aotea. Rm30 was used in the lower North Island to places like New Plymouth and Gisborne. Also used on the Wellington to Auckland route, Rm30 still holds the record for the fastest return journey between those two cities.

Last used on the run between Wellington and New Plymouth, Rm30 was withdrawn and sold to Silver Stream Railway in 1972. Originally stored at the Seaview site, Rm30 was transferred to the Silverstream Site in 1984. After a repaint in the late 1980s it returned to service on the railway being used sometimes as a supplement to the regular steam hauled trains and on other special occasions.