The M175 is one of the less common of the Bowman range; at least I have seen few other examples. It is, however, a typical Bowman style.
It has a horizontal boiler (3 3/4" x 1 3/4" diam.), fired by a meths burner with the wick inside the Bowman style slotted tube. The steam feed pipe exits from the bottom of the boiler, having it's input end inside the small dome on the top. This feeds, via a removable coupling, to the single acting oscillating cylinder (9/32" diam. x 7/16" stroke), directly coupled to a pin on the flywheel. The crank shaft has a small spur gear on the end oposite the flywheel and this engages a larger gear wheel, about 1 3/8" diam., giving a 5:1 reduction. The slow shaft has a small 1/4" diam, pulley. The steam exhaust is fed to the bottom of the chimney. The metal base is a typical Bowman style, 6" x 4 1/2", with Meccano standard holes round it's perifery.
I purchaced this toy in fully functional but tatty condition, complete with the original wooden box which, unfortunately, was barely holding together. I fully cleaned and repainted the engine and repaired the box with plywood. This was in my early enthusiastic days of restoring old toys and I think that, had I bought it later, I would have left it as it was.