There does appear to be quite some interest in the 48DS so here's a rivet-counter's guide to the type.   All photos are from my collection and are Ruston & Hornsby official photos, taken by their photographer in Lincoln works and on site at customers' premises.   Before locos were given the classification of DS (diesel shunter - standard gauge) and DL (diesel locomotive - narrow gauge), all Ruston locos were classified by horsepower. The progenitor of the 48DS was the 44/