The procedure to attach and remove the H class locomotives, as well as the actual trip along the Incline, was very slow.

They were intended to operate along the length of the Incline and take over Wairarapa passenger services from regular carriage trains.

Although able to traverse the Rimutaka Incline like the other six Wairarapa class railcars, RM 10 worked between Cross Creek and Masterton carrying mainly school children, parcels and light freight, and cans of milk and cream.

[6] The resulting mixed train (goods with passenger car attached) was subsequently referred to locally as The Arawa.

In 1969, the Wellington Branch of the New Zealand Railway and Locomotive Society purchased the remains of RM 4, 5, 6, and 9 for preservation at their Gracefield site.

Arriving in 2003, the incomplete frames of RM 9 became a source of spare parts that could be duplicated or restored for use on its sister car.

Originally, the Wairarapa railcars had wooden internal framing covered with steel sheathing.

RM 5's body had decayed so far the decision was made to replace the original wooden framing with steel.