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Auckland's Train Fleet

Rail Project

 Current Fleet  Interim  Long Term
 ADL/ADC (DMU)   SA Carriage Trains  New Rolling Stock
 ADK/ADB (DMU)   Locomotives  
 Silver Ferns    
 SX Carriage Trains    

Current Fleet

The current Auckland rolling stock fleet includes 19 Diesel Multiple Units (DMUs) purchased by Tranz Rail from Westrail, Perth, NSW, in 1992.  A DMU is a self propelled unit usually made up of a motorised driving unit permanently attached to a non-motorised trailer.  Each two-car unit can be joined to others to form longer trains. 

The recent addition of two 'Silver Fern' Railcars and two SX locomotive hauled carriage trains has expanded passenger service capacity.


There are 10 'ADL' driving units coupled to 10 'ADC' trailer units.

These units were manufactured in Australia by A. Goninan & Co Ltd and were originally commissioned between 1982 and 1985.

General Description

  • Seating capacity per car of 68 and standing capacity of 62
  • Tare weight of 42.97 tonne (ADL) and 35.75 tonne (ADC)
  • Maximum Service Speed — 80 km/hr
  • Length — 20.26 m over headstocks per car
  • Width — 2.74 m
  • Maximum height — 3.844 m
  • Step height from rail level — 1.124 m
  • Passenger doors — air operated sliding doors, two each side (four per car) 1.26 m wide

Design and Mechanicals

The DMU design is a semi-monocoque construction of flat and fluted panels of stainless steel. The units are designed to operate as two, four, six or eight car multiples. The ADL motor cars are each powered by two Cummins NT-855-R4 four stroke, six cylinder turbocharged engines, mounted horizontally each capable of producing 205 kW at 2100 rpm.

The transmission is a fully automatic Voith hydraulic turbo type T211R incorporating one hydromatic torque converter and one hydromatic fluid coupler.

Brakes are electro-pneumatic with wheel-mounted discs. Each car is fitted with both service and emergency braking systems utilising Westinghouse control equipment and Lucas Girling disc brakes with S.A.B. type CAU2 cylinder adjuster units. The parking brake is a type "F" S.A.B. spring parking brake unit.

House power is supplied by a diesel powered generator set mounted on each ADC trailer car comprising a General Motors Detroit diesel in-line 4-71T horizontal two stroke, four cylinder turbocharged engine producing a maximum output of 118 kW at 1500 rpm and a Stamford C334D brushless AC generator.

The ADL/ADC units are fully air-conditioned by two roof-mounted Sigma type RPR 25-MS1 units integrated with an air distribution ductwork system.


The ADL/ADC units have undergone an extensive refurbishment to improve passenger comfort and extend their useful life, costing $8.5 million.  The refurbishment was commissioned by the ARC through its service contract with Tranz Rail and was undertaken by ALSTOM at its Hutt Workshops.

The refurbishment involved.

  • Redesign of the front ends of each carriage
  • New passenger doors
  • A new passenger information system
  • Redesign of the drivers cab
  • Rewiring
  • Sound proofing
  • Complete interior redesign and fitout

ADL/ADC before and after refurbishment

 ADL exterior prior to refurbishment  ADL refurbished exterior
 Interior of ADL prior to refurbishment  Interior of refurbished ADL

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ADK exterior prior to refurbishmentThere are  nine 'ADK' driving units with nine operational 'ADB' trailer units. The ADK cars were manufactured by Commonwealth Engineering (N.S.W) Pty Ltd in 1967 and 1968. The ADB trailers were manufactured by Westrail.

General Description

  • Seating capacity per car of 70 — ADK and 64 — ADB
  • Standing capacity of 50 — ADK and 32 — ADB
  • Tare weight of 33.28 tonne — ADK and 15.8 tonne — ADB
  • Maximum Service Speed — 80 km/hr
  • Length 20.254m over headstocks — ADK and 15.85m over headstocks — ADB
  • Width — 2.74 m
  • Maximum external height — 3.844 m
  • Step height from rail level — 1.124 m
  • Passenger doors — air operated sliding doors, two each side (four per car) 0.915 m wide

Design and Mechanicals

The ADK cars are a monocoque design with a stainless steel structure. The ADB cars comprise a stainless steel superstructure built on a mild steel truss under-frame. The ADK/ADB units are designed to operate as two, four, or six car multiples. The ADK power car is powered by two Cummins NHHTO-6 four stroke, six cylinder turbocharged engines mounted horizontally with each capable of producing 155 kW at 2100 rpm.

The units are not air-conditioned but have roof-mounted radiators with cooling fans powered by a dedicated belt-driven alternator on each traction engine.

The transmission is a fully automatic Voith hydraulic DIWA type 501 that incorporates one torque converter stage for smooth acceleration and a final mechanical stage for economy.

The braking system on the ADK cars comprises an electro-pneumatic service brake with emergency system utilising a Westinghouse distributor, outboard disc brakes and Westinghouse actuators. The handbrake is activated by a hand-wheel, which applies braking force to both axles on the bogie under the driving compartment. The braking system on the ADB is as per the ADL except that the bogie brake arrangements are conventional brake blocks on tread with under-frame mounted air cylinders and pull rod connections to the bogie rigging.

House power is supplied by a 24 volt D.C. lead acid battery pack on each car charged on the ADK units by an engine-driven alternator and on the ADB trailers by an under-floor-mounted alternator belt-driven from the axle.


Tranz Rail Professional Services Group is preparing a future option feasibility study for the ADK/ADB DMU fleet. This includes structural examination of three cars and looks to confirm a provisional scope of works for refurbishment. This work will provide invaluable input into critical decisions regarding the future of the ADK's.  The picture below shows one of the design concepts under consideration.

ADK Concept 'Britomar' Barnacle Design

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 'Silver Ferns' (RM)

Silver Fern Rail MotorThe ARC has negotiated a four year agreement with Tranz Scenic for the supply of a four-car multiple unit (two Silver Fern units) to provide a single morning peak and return evening peak service Monday to Friday between Pukekohe and Auckland.

The Silver Ferns are Class RM Rail Motors, built by The Nissho-Iwai Company of Japan for New Zealand Rail.  Technically the Silver Ferns are DMUs consisting of a driving unit and trailer, but are designed for long distance services.  They were originally used on the Wellington to Auckland service. 

General Description

  • Seating capacity — 96 per set (192 per four-car set) configured for long-distance operations with limited standing space and handholds
  • Weight — 107 tonne
  • Maximum speed — 120 km/hr
  • Length — 47.4 m
  • End doors configured for long-distance operations

Design and Mechanicals

The cars consist of a ribbed stainless steel body on a corrosion resistant carbon-steel chassis and are powered by a turbo-charged Caterpillar D398TA producing 670 kW at 1300 rpm. House power is provided by a Caterpillar D330T driven generator set.

The Silver Ferns are fully air-conditioned.

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SX Carriage Trains

New SX at the StrandSeven SX carriages have been procured by the ARC from Zig Zag Railways in NSW, Australia. These carriages are owned by Macquarie Bank and have been leased on a short term basis to Tranz Rail to enable it to provide additional services to ARC.

The SX carriages were constructed in the early 1960's by Commonweath Engineering for Queensland Rail.  They have undergone an extensive refurbishment.

General Description

  • Seating Capacity - 134 Seated/84 Standing per three-carrriage train
  • Weight - 23.37 tonnes tare per carriage
  • Length - 17.55m per carriage
  • Doors are situated at the quarter points of each carriage, two each side

Design and Mechanicals

Motive power for the SX trains is provided by refurbished class DBR locomotives.


The SX carriages were extensively refurbished at Tranz Rail's Hillside workshops (Dunedin) in 2003, with the interiors refitted in a style to match the refurbished ADL units. Features include:

  • New fibreglass carriage linings and weather shields around the doors
  • Double doors with automatic opening and closing, and door controls standardised with other Auckland rail network equipment
  • Retractable steps to reduce the gap between the train and make it easier for passengers to get on and off
  • New rubber mounted windows for better insulation and reduced vibration
  • New lighting, air conditioning and heating systems
  • New floor coverings have been laid and the seats upgraded and re-covered
  • The bogies (wheel sets) have been upgraded and inspected and the wheels adjusted to match New Zealand standards

 SX exterior prior to refurbishment  Refurbished SX exterior
 Interor of SX prior to refurbishment  Refurbished SX interior

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SA Carriage Trains (Entering service during 2004)

The SA's are locomotive hauled carriage trains. 

Concept of SA carriageEach train will consist of a number of SA Carriages and an SD carriage fitted with a locomotive engineer's cab and locomotive control gear to enable push pull operation.

The SA trains are similar to the S cars used on the Wellington to Palmerston North 'Capital Connection' service and are based on the same British Rail Mark2 carriages constructed in the late 1960's.  The SA is an extensive rebuild of these carriages.

General Description

  • Seating Capacity - SA-70 Seated SD-50 Seated (approx)
  • Length - 20.3m over couplers
  • Doors are situated at the quarter points of each carriage, two each side.  Initial carriages may have end doors.

Design and Mechanicals

Motive power for the SA trains is provided by refurbished class DC locomotives.


The refurbishment programme will entail the following key elements:

  • All bogies refurbished and all wheels replaced with new wheels
  • The brakes converted to Tranz Rail specifications
  • The carriages lowered to facilitate easier boarding
  • Inter-car connections fitted to enable passengers and staff to move between carriages
  • The wiring renewed
  • New seats fitted
  • Floor coverings renewed
  • A public address system installed in all carriages
  • Lighting replaced
  • "ADL type" passenger information systems installed in all carriages
  • A generator set installed in each of the SD carriages to provide house power for air-conditioning, cooling, heating, lighting etc
  • A driving cab and control gear fitted to each of the SD carriages
  • Remotely operated power doors installed
  • The windows replaced with sealed units incorporating safety glass

The interior fit-out of the SA and SD carriages, like the SX carriages, will be comparable, from a passenger perspective to the ADL DMUs.

Interior of remanufactured SA carriage

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Class DBR

Refurbished DBR at platformDBR locomotives have been refurbished to haul the SX carriage trains.  DBR's are the smallest locomotive in Tranz Rail's mainline fleet.

  • Mainline diesel-electric locomotive
  • 950 Hp (710kw) upgraded to 1100Hp
  • Manufactured by General Electric 1965-66
  • Leased from Tranz Rail Ltd

Class DC

DC locomotives will be refurbished to haul the SA carriage trains.  The DC is the most common locomotive in the Tranz Rail fleet.

  • Mainline diesel-electric locomotive
  • 1500 Hp
  • Maximum Speed 100 km/hr
  • Weight 82 tonnes
  • Manufactured by General Motors as DA class 1961-1967 Rebuilt by Clyde Engineering Pty as DC in 1978-1980 

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Long Term Rolling Stock

The ARC will procure a fleet of new rolling stock, once funding is confirmed, through an international competitive tendering process. The successful tenderer will be required to design, build and maintain the new rolling stock.

Design Specification

The general configuration of units sought is a two-car Electric Multiple Unit (EMU) with two sets of bi-parting body-side doors at one quarter and three quarter positions per side per car seating approximately 130 passengers. The cars are to have a 100% level floor compatible with level boarding onto platform.

The units are to have a minimum design life of 30 years and are to be compatible with the infrastructure and operating practices of the Auckland Network.

While a two-car multiple unit reflects ARC's current conclusions on the best configuration to transport the estimated passenger demand, potential suppliers will be invited to tender alternative solutions. ARC will also consider solutions based on refurbished multiple units or locomotives hauling coaches in a push-pull configuration either refurbished or new.

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