This volume investigates the historical development and technical diversity of locomotive power in New Zealand from the mid-19th century through the mid-20th century. Authors A. N. Palmer and W. W. Stewart utilize their extensive knowledge of railway history to document the transition from early steam engines to modern diesel and electric propulsion. The work serves as a comprehensive technical record of the machinery that facilitated the nation's industrial and infrastructural growth.

The text is regarded as a foundational reference for railway enthusiasts and historians interested in the specific mechanical evolution of New Zealand's rail network. Its systematic cataloging and inclusion of rare industrial machinery provide a dense, authoritative resource for researchers in the field.