Extracts from Minimum Gauge Railways, by Sir Arthur Heywood.

As a guide to modellers planning to freelance their rolling stock we offer some words of wisdom from Sir Arthur Heywood’s “Minimum Gauge Railways: Their Application, Construction and Working“:

The wagons first put upon my line measured only 4 ft. by 2 ft. inside. It soon became apparent, however, that a gauge of 15 in. could carry with safety a much larger vehicle. In fact it may be taken as a reasonable rule that the floor area of narrow gauge wagons should not be less than four times the gauge in length and twice the gauge in width.

Based on a gauge of 16.5 mm, then, this would give minimum recommended internal dimensions of 66 mm long by 33 mm wide (2½” by 1¼” if you prefer to work using 1:24 scale).

(O)n the Eaton Railway I adopted an over measurement of 6 ft. by 3 ft. with 1 ft. 3 in. depth of side. The wheel base is, in all cases, half the length of the wagon. The … wagon above described carries 16 cwts. of coal, and from 20 to 22 cwts. of sand, road metal, bricks, etc., and weighs about 7½ cwts.

These dimensions work out as 79.2mm by 39.6mm (3″ by 1½” in 1:24).

My standard wagons are constructed of pitch pine with angle-iron rims, and the box sides are framed together independently of the wagon itself, thus a flat wagon is converted into a box wagon by merely placing this frame upon it. These sides, or “tops” as they have come to be called, are about 15 in. deep, and the wagons being constructed to a standard size, are interchangeable. An iron rim on each enables two or three of the tops to be placed one above another upon any wagon, to give extra depth.

(The photo above is of Jeff Saxton’s “top” wagon, based on Sir Arthur Heywood’s originals)