| ADK/ADB class railcar | |
|---|---|
 ADK 682 on a Papatoetoe to Westfield service, during its farewell trip | |
| In service | Australia: 1967–1993, New Zealand: 1993–2014, Mozambique: 2017–present |
| Manufacturer | ADK: Commonwealth Engineering ADB: Western Australian Government Railways |
| Built at | ADK: Granville ADB: Midland Railway Workshops |
| Replaced | Australia: WAGR Dd class & carriages New Zealand: 56-foot carriages |
| Constructed | 1967–1968 |
| Entered service | Australia: 1968 New Zealand: 1993 |
| Refurbished | 2007 |
| Number built | 10 sets |
| Number in service | 8 sets (running in pairs) |
| Formation | Australia: ADK+ADB New Zealand: ADK+ADB+ADB+ADK (originally ADK+ADB) |
| Fleet numbers | ADK 681–ADK 690 ADB 771–ADB 780 |
| Capacity | ADK: 74, ADB: 64 |
| Operators | Australia: Western Australian Government Railways, Westrail New Zealand: Tranz Metro, Transdev Auckland Maputo, Mozambique: MetroBus |
| Depots | Australia: Claisebrook New Zealand: Westfield |
| Lines served | Australia: Armadale Fremantle Midland New Zealand: Eastern Line Southern Line Western Line |
| Specifications | |
| Car body construction | ADK: 20.20 m (66 ft 3 in) ADB: 15.85 m (52 ft 0 in) |
| Train length | 37.75 m (123 ft 10 in) per two-car unit |
| Car length | ADK: 21.09 m (69 ft 2 in) over couplers ADB: 16.66 m (54 ft 8 in) over couplers |
| Width | 2.74 m (9 ft 0 in) |
| Height | 3.92 m (12 ft 10 in) |
| Floor height | 1.1 m (3 ft 7 in) |
| Entry | 1.1 m (3 ft 7 in) |
| Doors | Air-operated sliding doors, 2 pairs each side (ADK), one pair each side (ADB), 0.915 m wide |
| Maximum speed | 90 km/h (56 mph) |
| Weight | ADK: 33.3 t (32.8 long tons; 36.7 short tons) ADB: 15.8 t (15.6 long tons; 17.4 short tons) |
| Prime mover(s) | 2 x Cummins |
| Power output | ADK: 2 x 155 kW (208 hp), one engine per bogie |
| Transmission | Diesel-hydraulic |
| Auxiliaries | ADB: diesel alternator in former cab (one per four-car set) |
| HVAC | Heating only |
| UIC classification | (1A)(A1)+2′2′ |
| Braking system(s) | Electro-pneumatic |
| Coupling system | Australia: Norwegian coupling NZ: Kidney link & pin |
| Multiple working | Within class |
| Track gauge | 1,067 mm (3 ft 6 in) |
The ADK class are a class of diesel multiple units that were previously operated by Western Australian Government Railways (WAGR) in Perth, and later Transdev Auckland on Auckland's suburban rail network, and are currently operated by MetroBus in Maputo, Mozambique. Originally built by Commonwealth Engineering and the Midland Railway Workshops for WAGR in the late 1960s, all but one were sold in 1993 to New Zealand Rail, and were then owned by Auckland Transport. The units were completely withdrawn from service in New Zealand on 5 December 2014, following completion of electrification of Auckland's network.