The Stephenson valve eccentrics. The gears on the inside engine can be seen - I think these serve to couple the Fell wheels.

The driven Fell wheels gripping the centre rail.

An example of the Fell rail and new and used (rear) brake blocks.

The Fell rail brake blocks on the loco.

As a youngster, when railway books were something of a rarity, I frequently found myself poring over "Railway Wonders of the World" or some similarly titled book, and inevitably there would be a photo of a rather unprepossessing tank loco on the Rimutaka incline, together with a caption about the "Fell system". It didn’t mean much to me then and I was much more interested in pics of BR main line locos.

It was not until my previous visit to New Zealand that I finally worked out where the Rimutaka incline was – near Wellington – and when thoughts turned to another vacation in NZ this year, the decision to book a homestay near Wellington was in part because I wanted to track down the famous incline. We flew to Auckland and took the "Overlander" train from Auckland to Wellington, a 12 hour trip over the historic North Island Main Trunk, through great scenery. We picked up a hire car in Wellington .

The Rimutaka hills are north east of Wellington, to the east of the Hutt Valley. The road over the hills is spectacular – think of the Bwlch between Dinas Mawddwy and Dolgellau and multiply its height and length several times and you get the idea.

The railway line over (now through) the Rimutakas, the Wairarapa line, is a secondary route and is now primarily a commuter line, terminating at Masterton, with USA made single-ended diesels hauling very smart and modern coaches.

The Rimutaka Incline

At Featherston, the last station before the Rimutakas coming from the Wairapara coastal plain, a small museum has been built to house the sole surviving Fell loco, No 199 (Avonside 1075 of 1875), together with a number of artifacts from the incline. There is also a brake van from the incline.

The incline was opened in 1878 and closed in 1955 when the new tunnel was opened, and is now a cycle/walking track. Although it was possible to build a conventional railway approach on the Wellington side as far as summit, the terrain was just too difficult on the Featherston side, and a tunnel was too expensive and probably technically very demanding at that time. The Rimutaka incline was the principal example of the application of Fell technology. Rack railways became rather more common.

The central Fell rail (a standard bullhead rail mounted on its side, on pedestals in the centre of the track) served both as an aid to climbing (using horizontal gripper wheels under the locomotive) and also for braking, using caliper style brakes under the loco and each brake van. The average gradient is around 1 in 15. The track must have been firmly anchored to the ground to resist the climbing and braking forces. Locos were cut into the train at intervals, presumably to reduce the strain on couplings, so marshalling at Cross Creek (the bottom of the incline) and Summit must have been a lengthy process. Trains were brought into Cross Creek and Summit by conventional traction.

There are several tunnels on the incline, including the 576m Summit tunnel. It is useful to carry a torch.

There were six fell locos, four by Avonside, Nos 1072 – 5 of 1875, and two later locos of similar design by Nielsen 3468/9 of 1886, with Joy valve gear rather than Stephenson. They were all externally 0-4-2Ts, but internally had two cylinders for driving the horizontal fell wheels. There were separate regulators for the inside and the outside engines. The inside cylinders do not seem to have adjustable valve travel. 

The brake blocks were said to be replaced after each trip. Water was used to cool/lubricate the Fell rail when braking.

On meeting the Fell rail leaving Cross Creek yard, the fireman wound a handle which squeezed the Fell wheels onto the centre rail, with a force of around 20 tons. Speed on the incline was very slow and it was possible for passengers to walk/run beside the train. Latterly, normal passenger services were operated with single unit railcars, which just used the Fell rail for braking on the descent.

One suspects that it was always intended to replace the incline, and it is surprising it lasted until 1955.

Worksplate from No 199.

Horsehoe Gully, towards the top of the incline. The line curved across the gully on an embankment, and then continued off to the left.

The southern entrance to Summit Tunnel

Summit tunnel. The far end can just be seen.

Upper Hutt station. A train to Masterton is arriving. One of the pair of ex-Otira electric locos which tops and tails a train of ex-BR mark IIs is stabled.