NZR RM class (Wairarapa)

NZR RM class Wairarapa
The sole surviving Wairarapa railcar, RM 5 (Mahuhu), currently undergoing restoration at the Pahiatua Railcar Society.
In service	1936–1955
Manufacturer	New Zealand Government Railways
Built at	Hutt Workshops
Entered service	1936-09-07
Number built	7
Number in service	None
Number preserved	1
Fleet numbers	4 – 10
Capacity	RM 4-9: 49 passengers; RM 10: 25 passengers
Operator	New Zealand Government Railways
Line(s) served	Rimutaka Incline; Wairarapa Line
Specifications
Car length	57 ft 11 in (17.65 m) over buffers
Maximum speed	60 mph (97 km/h)
Weight	29.50 long tons (30.0 t)[citation needed]
Engine(s)	Leyland petrol engine Diesel engine
Power output	130 hp 120 hp
Transmission	Mechanical
UIC classification	2-A
Gauge	3 ft 6 in (1,067 mm)

The NZR RM class Wairarapa railcar (or Rimutaka railcar) was the first truly successful class of railcars to operate on New Zealand's national rail network. They entered service in 1936 and were classified RM like all other classes of railcars in New Zealand; they came to be known as the "Wairarapa" class (and sometimes as the "Rimutaka" class) as they were designed to operate over the famous Rimutaka Incline to the Wairarapa region on the Wairarapa Line. They also acquired the nickname of "tin hares" in New Zealand railfan jargon. The first two to be introduced re-used the numbers RM 4 and RM 5 that had previously been used by the withdrawn experimental Model T Ford railcars. The class consisted of six passenger railcars, and one passenger-freight railcar. It is often described incorrectly as a class of six railcars.

Background

The Rimutaka Incline over the Rimutaka Ranges posed a severe time delay to any service operating between Wellington and the Wairarapa region. At one end of the Incline, a train had to have its engine replaced by multiple members of the H class, as the H class locomotives were specially designed to work the steep and difficult Incline. Once they hauled the train the length of the Incline, they were then replaced by a single ordinary engine, and the procedure to attach and remove the H class locomotives as well as the actual trip along the Incline was tremendously slow.

The Wairarapa railcars were designed as an answer to this problem. They were intended to operate along the length of the Incline and take over Wairarapa passenger services from regular carriage trains. In design, they resembled a bus, and unlike a usual single-unit railcar that has a driving compartment at each end, the Wairarapa railcars only had one driving end, necessitating that they be turned at the terminus of their journey. An additional characteristic of the Wairarapa railcars' design was that their body had to be built higher than an ordinary railcar to easily navigate the raised Fell centre rail on the Rimutaka Incline.

The first six of the class (Rm 4 to Rm 9) were designed to carry 49 passengers with their baggage. Rm 10 was built as a mixed freight and passenger railcar with seating for 25 passengers ^{[1] [2] [3] [4]}

Operation

Upon their introduction to service in 1936, the Wairarapa railcars proved to be the first successful class of railcars in New Zealand, although it is arguable that only the financial constraints of the Great Depression thwarted the success of the earlier Edison battery-electric railcar. The Wairarapa railcars immediately slashed running times between Wellington and the Wairarapa, and would operate the full length of the Wairarapa Line from Wellington to Woodville, and then utilise the Palmerston North - Gisborne Line through the Manawatu Gorge to access Palmerston North. They proved popular with passengers, fully replacing a locomotive-hauled carriage train known as the Wairarapa Mail in 1948, though local mixed trains continued to operate.

Withdrawal and preservation

The replacement of the Rimutaka Incline by the Rimutaka Tunnel in November 1955 meant that the main reason for the Wairarapa railcars' operation ceased to exist. Locomotive hauled trains were now competitive in timings with the railcars, which were soon withdrawn.

Most of the railcars were eventually cut up for scrap, but one was saved by the Silver Stream Railway. It was rescued in a considerably run-down condition. The remains of Rm's 4, 6 and 9 were also saved. After being operated at the storage site at Seaview Rm 5 was transferred to Silver Stream and was stored until it was leased to the Pahiatua Railcar Society in 1992 and is now being restored with the intention of returning it to full operability. The chassis of Rm 9 is also leased by Pahiatua; the remains of the other 2 cars were cut up at Seaview after donating any salvageable parts.

Notes

1. ^ Stott, Bob. "The Rimutaka Incline: Yesterday and Today". Southern Press, 1984, p.26
2. ^ The Arawa, a rail-car of a new type, taking its trial run over the Hutt Line on Saturday. Evening Post, Volume CXXIII, Issue 39, 16 February 1937, p.9
3. ^ Beckett, Mike. "The Tin Hares". Rimutaka Incline Railway Heritage Trust, 2005. Newsletter No.10.
4. ^ Albert Percy Godber Rail motor No 10 "Arawa", 1937 Alexander Turnbull Library.

External links

• Pahiatua Railcar Society - RM 5
• Photo of RM 6 blown off the tracks by wind gust, 9 October 1936.
• Photo of railcar at Kaitoke on the last day of operation of the Rimutaka Incline, 29 October 1955
• Article and photos of the railcar "Maahunui" from the New Zealand Railways Magazine, 1936