Condensed from an article written by
Tom McGavin in the New Zealand Railway Observer issue 140 of summer
1974.
The Wairarapa type railcars, numbered from "Rm" 4 to
"Rm" 9 inclusive, they were named after famous Maori
canoes of ancient times: Maahunui, Mahuhu, Mamari, Matahourua,
Mataatua, and Araite-Uru respectively. A seventh car of generally
similar outward dimensions, named Arawa ("Rm" 10), had
a small 20-seat passenger compartment and a large compartment
for parcels and small lots of goods. This one was provided for
a local service between Cross Creek and Masterton and it was only
occasionally used elsewhere.
As built, at the Hutt Workshops, each of the six passenger cars
was fitted with a Leyland 10-litre petrol engine with a rated
output of 130 b.h.p. Transmission was through a Lysholm-Smith
fluid torque converter to a final drive unit mounted on the single
rear driving axle. This single axle, with wheels 3ft. 2.5in. in
diameter, was a distinctive feature of these railcars, the large
wheels being necessitated by the need for the axle to clear the
raised centre rail on the Incline. To accommodate the engine beneath
the floor, the latter was raised to the high level of 4 ft. 42in.,
more than 12 inches higher than usual. The goods railcar was powered
by a 120 h.p. Leyland diesel engine and the passenger cars received
similar engines after a few years.
Ready for service, including 35 gallons of petrol in the fuel
tank and 40 gallons of water to serve the toilet, each passenger
railcar weighed 13.35 tons, of which 7.1 tons rested on the driving
wheels, according to a 1938 diagram. An under-floor compartment
at the rear and another inside the car opposite the toilet, were
provided for the accommodation of luggage up to a maximum of one
ton.
Westinghouse air brakes were provided to operate on brake drums
at the ends of each axle and Fell centre-rail grip brakes, hydraulically
worked, were available for use on the 1 in 15 Rimutaka Incline.
A driving cab with seats for driver and guard was provided at
one end only, next to the passenger entrance, so the cars had
to be turned at the end of each journey for normal running. A
reverse gear was provided however for manoeuvring purposes. Emergency
passenger exit doors were provided at the rear of the car, as
in bus practice. Fully laden, including eleven standing passengers,
the all-up weight would have been about 18 tons.
