88 Seat Articulated Twinset Railcar Details by Selwyn Roberts RM133 parked at the Whangarei Locomotive Depot (date and photographer unknown) Background The events that led up to the entry into service of the twin-set railcars were rather a convoluted tale. Following alleged lengthy investigations during the mid to late 1940s, an order was placed early in 1950 with the Drewry Car Company, of London, England, for 35 articulated twin-unit railcars, with a seating capacity for 88 passengers. Ten were to be specially adapted for use over the Rimutaka Incline and 25 were to be for general service. However, with the rapid construction of the Rimutaka Tunnel, and the delay in building the railcars, all 35 were built to the same design. Manufacturers The Drewry Car Company had been in business for over 40 years, and was a designer of railway locomotives and railcars. The actual construction of equipment was contracted out to railway equipment builders, with these railcars being built by the Birmingham Railway, Carriage and Wagon Company Ltd, Smethwick Works, Birmingham, England. The Italian firm of Fiat was also involved, as this company had available an underfloor prototype diesel engine developing 210bhp (156kw). At the time the Fiat Automobile Company led the world in developing a horizontal-type engine, which was naturally aspirated. Construction The design of these railcars, which consists of two bodies mounted on three bogies, was governed by stringent limitations on overall dimensions and on axle loadings. The outer bogies were the driving bogies, with both axles being powered. Maximum height above rail was 11ft 3in (3.429 metres) and the axle loading with full complement of passengers, crew, and luggage had to be kept within 11 tons (12.32 tonnes). Other leading dimensions are as follows:     Type Diesel-Mechanical Railcar     Seating 88     Introduced 1955     Number in class 35 (Nos 100 - 134)     Manufacturer Birmingham Railway, Carriage and Wagon Company Ltd     Gauge 3 ft-6 ins     Axles Three 2 axle bogies     Diameter of wheels 2ft 7in (787 mm)     Length 105 ft     Width 8 ft-10 ins over body     Weight in working order 63.1 tons     Engine Fiat Diesel     Transmission Diesel mechanical through gearbox     Power 210 hp x 2     Max Speed 65 mph The framework of these railcars was protected against corrosion and bodies insulated against heat, cold and noise. Passenger Accommodation Each railcar had seating for 36 passengers in number 1 body and 52 in number 2 body, giving a total of 88. The seats were a four-position reclining type, with legroom of 3ft (913mm) between each seat. They were arranged in pairs on each side of a central gangway. The seats could be turned by reversing each pair of seats, but seats could not be arranged to face each other, as there was insufficient legroom between the seats. The original seats were upholstered in red leather and later on vinyl. The simple reclining mechanism was arranged so that, when the lever in the armrest is lifted, the seat returned to the normal position. The ceiling lights were arranged along the centre of the ceiling with individual switches on the walls above the windows. The fittings were simple but attractive, and blended harmoniously with the other interior furnishings. Heating of the passenger compartments was from the engine cooling water, controlled by an air thermostat in each compartment. The heating for the drivers and guards compartments was on a separate circuit and regulated individually. A luggage compartment was provided immediately behind the drivers cab in number 1 body. There was a separate guards compartment between the luggage compartment and the passenger vestibule. There were two toilet rooms, located at the articulated end of number 2 body. Engine Equipment Motive power was provided by two FIAT (Italian Automobile Assemblers of Turin) type 700.040 horizontal 6-cylinder, naturally aspirated diesel engines of 20.15 litres each. The cylinder bore was 150mm diameter and the piston stroke was 190mm meaning these dimensional sizes made it an under square engine. Designed prior to WW II principally for use in small Italian Navy boats, where they ran for many hours at constant speeds and loads, they were totally unsuited to the rigors of life on the railcars. An engine was mounted beneath the floor of each body, being supported from the underframe in resilient mountings, and was arranged for dry sump lubrication, with the lubricating oil supply tank of 10 gallons (45.5 litres) capacity, being mounted in the underframe. The original rated output of each engine at 1550 rpm was 210 bhp (156 kW). The engines normally idled at 550rpm. A 150-gallon (682 litre) fuel tank was transversely mounted in each of the two under frames and allowed the railcar to travel about 1038 miles (1682 kms) before needing to refuel. Transmission Power developed by each engine was transmitted by mechanical transmission through a Vulcan-Sinclair type fluid coupling, and a Wilson-Drewry 5 speed epicyclic gearbox, to final drive units mounted on both axles of each specially reinforced driving bogie. The centre bogie carrying the articulated joint was not driven. The gearbox was arranged for electro-pneumatic control, and all of the running gear was pressure lubricated by an oil pump driven off the input shaft. The final drives were Bi-directional David Brown Spiral bevel gear driving to the outer axle of each driven bogie. The inner drive of each was fitted with a constant-mesh bevel output pinion, which transmitted the drive by the inter-axle transmission shaft to the outer axle. Controls The Westinghouse electro-pneumatic system, specially developed for multiple unit working, allowed for simultaneous control of the engines throughout the railcar. The system controlled the change speed and reverse gearbox and of the engine throttle (type W valve). In the event of a fault developing in this control a cut-out cock is provided to enable the system to be operated pneumatically without the electrical feature. The Westinghouse self-lapping straight air brake type W.2.E. Controlled braking, as well as emergency and dead man systems. For multiple-unit operation of up to a maximum of three railcars, English Electric type jumper cable connections were used. Passenger Services They first entered service in March 1955 and were used on nine main routes throughout New Zealand, namely Auckland - Whangarei - Okaihau, Auckland - Rotorua, Auckland - Te Puke, Auckland - Taumarunui - New Plymouth, Wellington - Napier - Gisborne, Wellington - Masterton - Palmerston North, Christchurch - Picton, Christchurch - Greymouth - Ross, and Christchurch - Dunedin - Invercargill. In April 1968 following a suggestion from the Hamilton City Council, RM131 was completely refurbished inside and painted outside with light blue with violet bands running along the sides, for a luxury service between Auckland and Hamilton. The service was not a success due to low patronage so the railcar was placed on a new daylight Auckland to Wellington service which proved very popular. Two more railcars, RM119 and RM123 were similarly modified and the service ultimately became known as the 'Blue Streak'. During their heyday, each railcar was running around 70,000 miles per year carrying thousands of passengers safely to their destinations. There were however a number of breakdowns primarily due to the Fiat engines and owing to lack of replacement engine parts, all were retired from service by the end of 1978. This was not to be the end of the story of these railcars as many of them had their motors removed and were modified to serve as passenger carriages until around 1984. They were all painted lime green and were affectionately called 'Grass Grubs. The articulated Twinset Railcars have been assured a place in New Zealand passenger railway history as the vehicles that bridged the gap between steam hauled provincial expresses and the modern diesel hauled services. They are affectionately remembered by many of the passengers who travelled in them and our unit will be a welcome addition to New Zealand's preserved heritage fleet when its restoration has been completed. Check out the latest restoration progress on the Drewry Twinset RM121 here.