In 1950, when the N.Z.R. had already decided to obtain diesel-electric locomotives
for the North Island Main Trunk line, sixteen oil-fired "Ja" class engines were
ordered from the North British Locomotive Company, Glasgow. The locomotives were
intended as a stop-gap at a time when secondary mainline power was proving inadequate.
Apart from the fact that they were oil-fired, the Scottish engines differed little
from their Hillside Ja's. An important variation, however, was the fitting of
French T.I.A. "blow-down" equipment to reduce boiler scale and to enable sludge
to be ejected.
The locomotives were originally assigned to important duties on the Auckland-Paekakariki
section, and were also used on the Northland and Hawke's Bay routes. Towards the
end of their service they were employed almost exclusively in the Auckland district,
where their duties included the haulage of Main Trunk expresses between Auckland
If the North British locomotives possessed the potential for high-class performances
similar to those of the Hillside engines, they lacked the opportunities. Even
the most favourable stretches of the Auckland-Frankton main line were not conducive
to spirited running of the kind traditional on the Canterbury Plains.
Nevertheless, they proved capable of running at mile-a-minute speeds on level
track with medium-weight expresses.
Ja1275 was retired in March 1968 and was purchased by Les Hostick. It was put
into storage at Te Awamutu Railway Museum until 1994 when it was leased to Mainline Steam. It was moved to our Parnell
depot where it has undergone an extensive overhaul returning to service in October
Cavalcade of New Zealand Locomotives. A.N. Palmer and W.W. Stewart