Firefield Hill is an engine shed in a large coastal town at the southern end of the former (and fictitious) Wessex & South Midland Railway. The company policy of leasing engines from LNWR and the GCR and subsequently from the LMS and LNER, is still very much in evidence. Although the GWR and SR now bring in trains from London and elsewhere, creating the wide variety of locos on display.

The period covered commences in the 1930s and extends up to the early 1960s and, as the exhibition progresses, it ensures that the stock on view is constantly changing.