Very little change has taken place in the shape of coupling hooks over the last 150 years. The drawing of a hook shown here represents post-war practice. It has been made from the original, cut from a scrapped 16T mineral wagon, now to be found in Dean Hall, the club rooms of the Manchester Model Railway Society.

Basically, a hook when loaded is trying to resist being straightened out, so the cross section is increased at the point where this would happen. In general, the majority of hooks from the trade supplying gauge O modellers follow this principle, a minority however do not.

The thickness of model hooks, whether etched from brass or stamped out from steel sheet, is nearly always below scale, though the hooks are still adequately strong. For a satisfactory appearance they have to be soldered together in pairs and filed to profile towards the point of the hook.

Hooks which are cast by the lost wax process are usually properly shaped and tapered.

Hooks should be chosen to suit the era of the model. For example, a badly proportioned hook can spoil the front of a locomotive.

In all the years the writer has been modelling he has only had one breakage of a plastic hook, one case of straightening of a cast white-metal hook, and no failures of hooks made from brass etches or stamped out of steel sheet. The links are the weak point in gauge O couplings as they tend to straighten out. This can be cured either by soldering the butts or by making new links from spring steel.

The overall length of the three links varies between 33in. and 36½in. (scale 19.14mm to 21.2mm), and a typical diameter of the iron is 1½in. (scale 0.88mm).

Data Source: Railway company drawings, Coal Trade Wagons, L R Tavender, HMRS Journal. Illustrations reproduced by kind permission of the author.

Article compiled by Tom Lindsay.