There were two different models of outside cylinder 0-4-0 tank engine, plus a smaller one with a single geared inside cylinder, also a 4-4-0 tender engine which is the best known. Plenty still around, as they were solidly made and great fun! If you google Bowman Steam Models or similar, plenty of information and photos on the web.

When I was a little lad back in wartime my father aquired a Bowman 4-4-0 tender loco,with Hornby tinplate track and Hornby trucks. It went like stink around track laid on the front room floor so my father removed a couple of the burners to make it a bit more docile,plus some lead weights in some of the trucks to give it a load, when I was about 12 father bought an old o gauge 3 rail electric loco so the Bowman was put to one side. My elderly neighbour at the time had pre war run a thrashing business and had retained his engines plus he also had a fairground roundabout centre engine,I really liked that engine .So the Bowman engine ,was converted into an overtype engine,ie the bowman boiler with the cylinders and loco wheels on top ,held together with Meccano fire box.With two cylinders it made quite a good stationary engine with plenty of power to drive Meccano models, The Meccano has survived but I just cannot remember what happened to the dismantled Bowman,