"The design and construction of a computerized data base for all kinds of steam technology for the period 1600 to 1940 is described. The data are contained within text-based files generated by conventional word processing packages, with entries formulated using a controlled vocabulary to facilitate subsequent retrieval, and is arranged chronologically in a format appropriate for the class of artefact being described. The database now has 24,000 entries for both individual artefacts as well as classes of such artefacts, has been generated from 17,500 references drawn from English language technical literature, and is suitable for storage and use on a personal computer of modest size. The technical context and significance of the triple-expansion engines in the Spotswood pumping station, Melbourne, is examined to show how some of the key questions which remain unanswered about the way this particular technology was developed can be identified."