[1] The first batch of seven DSA class locomotives arrived in 1953 from the Drewry Car Company, with another fourteen coming from that maker the following year.

No further DSAs were purchased until NZR placed an order with Mitsubishi Heavy Engineering for a further ten locomotives in 1967, all of which were delivered later that year.

[2] Designated as model A-2, these locomotives were built by the Vulcan Foundry of English Electric for the Drewry Car Company.

They weighed 29.5 tons ready for service and were powered by a Gardner 8L3 diesel engine producing 204 hp.

[3] DSA 234 has been restored to running condition and is operated by Oamaru Steam and Rail in North Otago.

This resulted in the cosmetic appearance of the locomotive changing with a new housing mounted on the left-hand side running board to protect the torque converter while several hood panels were fitted with large mesh sections to improve cross-ventilation.

The initial batch of ten locomotives were fitted with National M4AA6 diesel engines developing a slightly higher 250 hp powering a Hunslet friction clutch and four-speed gearbox but this gave trouble and the last batch were fitted with hydraulic transmissions, again powered by the 250 hp M4AA6.

In 1991, DSA782 was returned from loan to Rail Base Systems after the conclusion of track recovery beyond Middlemarch on the Otago Central Railway.

Although obsolete, the DSA was overhauled and dispatched to Wairoa on the Palmerston North-Gisborne Line for use as a shunting locomotive in 1995.

The DSA was then trucked to Dunedin and overhauled at Hillside Workshops, during which time it was repainted in a variant of the Tranz Rail "Cato Blue" livery.