Caustic soda liquor tank wagons were frequently transferred to china clay traffic including Powell Duffryn-built TTAs (Design Code TT072F/G constructed in 1965 for TRL). The wagons have conical ends and lagging panels on the barrel. They look similar to two-axle petroleum tank wagons, hence using the Graham Farish model as a basis for modelling at least one as closely as possible allowing for the barrel diameter. The challenge was modelling the conical ends. Otherwise, it is a comfortable conversion to complete. Similar techniques can be used to complete models of almost any lagged 46t tank wagon including bitumen and fuel oil tank wagons.
Painted and weathered: the finished TTA model is close enough in shape and size to pass muster on an ‘N’ gauge layout, and fits in well in yard scenes with other china clay wagons.
Conical ends for ‘N’ gauge models can be made from thin brass sheet cut to a size just larger than the barrel end (A). A hole is drilled in the middle using a 0.7mm drill. A vee-shaped slot is cut into the brass with its apex at the drill hole (B). The edges of the slot are brought together so they touch and are soldered in place (C).
The end is shaped using a file and abrasive paper along with finger pressure (D). The ends are mated with the barrel and the outline scored in place so the end can be trimmed to fit (E). The alternative is to use styrene card for the ends, although this is not ideal for ‘N’ gauge (F).
The completed TTA with etched ladders and over-ride guards applied to the underframe. Etched walkways would have looked better, although such details are not readily available at the time of writing. The original was used as a stand-in.
Two screws secure the barrel to the underframe on Graham Farish TTA models.
The ends of the plastic barrel are cut away with a razor saw and cleaned up before the metal ones are fitted using epoxy glue.