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The New Zealand Railways Magazine, Volume 3, Issue 3 (July 2, 1928)

New Rail Motor — Tower Wagon for Otira — Superstructure Constructed Locally

page 26

New Rail Motor
Tower Wagon for Otira
Superstructure Constructed Locally

An interesting type of rail motor vehicle—an illustration of which appears with this article—has just been completed by Hardy Railmotors, Limited, of Slough, Bucks, for service on the New Zealand Government Railways. This vehicle, which is to be used as a tower wagon for the inspection and repair of overhead cables, will be used by the signal and electric branch on the electrified section of the New Zealand Government Railways between Christchurch and Greymouth, and will thus operate through the longest tunnel in the British Empire — the Otira tunnel—which runs beneath the famous Arthur's Pass in the Southern Alps of the South Island of New Zealand. The tunnel itself is about 5 1/4 miles in length, and the line through it is a single one on a gradient of 1 in 33. The shunting yard at Arthur's Pass is 2420 feet above sea level, and snow is fairly constant during the winter months.

(Photo A. P. Godber) Petrol-electric crane, for New Plymouth, undergoing trials at Petone Workshops.

(Photo A. P. Godber)
Petrol-electric crane, for New Plymouth, undergoing trials at Petone Workshops.

Superstructure.

The superstructure of the vehicle, consisting of a tower and accommodation at each end for the driver, has been designed by the chief mechanical engineer of the railways (Mr. G. S. Lynde), and will be constructed in the New Zealand Government Railway workshops. It will be approximately 15ft long and 8ft wide, and will house the driver, the engine, and repair material for the overhead cable. The gauge of the car is 3ft 6in, and the wheel-base 10ft, and it will be required to operate on a 3 per cent. up-grade with a total load of 9000lb on the chassis and a gross training load of 14,000lb at a speed of 15 miles an hour. All controls are duplicated at each end to allow the vehicle to be operated in both directions with the full trailing load.

The car has a 6-cylinder engine with cylinders 100mm. bore by 140mm. stroke, developing 80 b.h.p. at 2000 r.p.m. The valves are placed on one side and are of large diameter—inlet valve of nickel steel and exhaust valves of stainless steel. The crank-case is of valves of stainless steel. The crank-case is of aluminium, and the capacity of the sump is three gallons. Lubrication is by gear pump through a large strainer to the main and cam-shaft bearings, and through the crank-shaft to the big end bearings, efficient relief valves being fitted to the whole system. Ignition is by high tension magneto, and an electric starter and lighting are also fitted. Efficient cooling is secured by two gilled tube radiators with cast tanks and side brackets mounted one at each end of the vehicle, circulation being carried through the engine and the two radiators in series by a large capacity rotary pump. A fan is also mounted at the engine end.

Speeds and Brakes.

All gears and shafts run in oil on ball or roller bearings, and are totally enclosed. The gears are of the constant mesh type, engaging by dogs. Four speeds in both directions are provided, namely, 16 m.p.h. at normal engine revolutions page 27 on top gear; 8 m.p.h. on third, 4 m.p.h. on second; and 2-1-3 m.p.h. on low. Reverse is effected by a subsidiary gearbox placed between the clutch and main gearbox, giving direct drive through the box or reverse through intermediate gears. The drive is taken from the gearbox centre drive by cardan shafts with universal joints to both axles independently, which are of the full floating bevel type and are fitted with tapered roller bearings. Springs are of the laminated type, hardened in oil. The wheels are of 30in diameter on tread, and are of disc type with rolled steel tires. Two brakes are provided, one acting on a drum at the back of the gearbox and so through the transmission on all four wheels, the other being a screw-down hand-brake acting through brake-blocks on all four wheels. Sand boxes are fitted at each end and the petrol tank has a capacity of 17 gallons.

In order to enable the vehicle to be tested under working conditions, special temporary axles of standard (4ft 8 1/2 in) gauge were employed, with the full load on the chassis and a trailing load 1 1/4 tons in excess of what was specified. With this gross load, the vehicle climbed a gradient of 1 in 24 without difficulty at 18 miles per hour with the engine accelerating on the steepest part of the gradient. Moreover, the load was securely held on the gradient by the foot-brake alone.

Without Advertising.

Suppose all advertising were suppressed, what would happen? The cost of living would immediately rise. Unemployment would increase. All newspapers as we know them to-day would cease to exist. The work of Government would be hindered.—Gilbert Russell in “Nuntius.”

The new Rail Motor for use as a tower wagon for the inspection and repair of overhead cables on the electrified Otira section of the N.Z.R.

The new Rail Motor for use as a tower wagon for the inspection and repair of overhead cables on the electrified Otira section of the N.Z.R.