In an idle moment I was pondering....................... Tank engines have the obvious advantage of not needing to be turned. Clearly you cant get the range of a tender loco, and - I imagine you must come up against weight limits if you want a big one. But in the immediate pre grouping period a number of large passenger & freight tank locomotives were built, such as the 'Rivers' & the GWR & LNWR 8 coupled freight locos. From looking at the figures - and the performance of the Brighton tanks on the run to Rugby it seems as though range was not an issue which makes me wonder why greater use was not made of tank locos - for example why wasn't the SDJR 7F built as a tank rather than a tender loco?