Until the arrival of canals, railways and finally roads, coastal shipping was the UK's prime method of cargo transport: with nowhere on the mainland more than 70 miles from the sea, it was the obvious way to transport goods in bulk. Even after the coming of canals and railways shipping was still a major player, working with these alternative carriers rather than against them. Only the arrival of motorways and containeristaion put paid to them, in exactly the same way that railway branchline pickup goods became uneconomical.
Coastal shipping reached its zenth with the arrival of the steamer, massively lessening the impact that winds (or lack of them) could have on journey times, and from the late ninetheenth century until the early 1960s, coasters would be a common sight in docks and larger harbours.
Coasters fall broadly into two groups, liners and tramps. Liners belonged to fleets owned by shipping lines, who specialised in regular contract work, while most tramps were owned by smaller organisations or even individuals, and made their living by picking up and delivering what ever they could ad hoc - sometimes a rather precarious hand-to-mouth existance.
The overall look of the steam coaster changed very little over the years, especially as the big lines often sold their older vessels on to smaller concerns, so older ships might still be around decades after their launching.
'Roamer' is not an exact copy of a prototypeimply because I couldn't find any plans for what research had suggested to me was the archetypal small coaster. So I've taken bits from various plans to replicate what I was after. You'll notice that this version ahs an open bridge, with no wheelhouse. Amazingly, given Britains's weather, this was quite normal practice, especially in the earlier days, but there were still examples like this through to the 1950s, and I have one image from the 1960s of a working coaster still with an open bridge.
This means that 'Roamer' should be appropriate for any time between the 1890s and 1960s. The model is high-poly, but has five levels of LOD as well as the main mesh, so shouldn't create huge problems on most systems.
Lastly, thanks to PEV for his fantastic tools, and to fellow members of Trainz Carriage and Wagon Works, for their knowledge, suggestions and help.