Number in Class: 10
|Tender Weight: 38.0 tons||Total Weight: 88.5 tons||Adhesive Weight:
|Length over Buffers:
|Total Wheelbase: 50' 3"||Engine Wheelbase: 27' 3"||Coupled Wheelbase:
|Tender Wheelbase: 14' 6"||Driver Wheel Dia.: 49"||Cylinders HP:
Two - 18" x 24"
|Grate Area: 28.3 sq ft||Evaporative Area:
1459 sq ft
254 sq ft
21580 lbs f
|Coal Capacity: 5.0 tons||Oil Capacity:||Water Capacity:
These new Pacifics were an enlarged and improved version of the 1901 'Q' and were intended for heavy haulage on the North Island Main Trunk line.
The capacity of the tender was increased that made longer runs possible. these powerful locomotives gave little trouble in service and were highly regarded.
These ten Baldwin built locomotives
were rebuilt with 'Ab' boilers and with altered cab and tender.
The 'Aa' class was one of the most successful of the classes ever to work on the NZR.