By Vic Shattock
The Miniature Locomotive
The building of small steam locomotives involves many problems some of which are due to the fact that many items are required to be in places where it is difficult to use a wrench or even the fingers in order to install them. One of such places is the smoke box or front end. Here is located the steam lines to the cylinders, the blower and piping, possibly a feed-water heating coil; add to these items the superheater elements and the lubricating oil lines leading into the steam lines to the cylinders, in the event the latter method is used. Each item has to be fitted and connected by union nuts or flanges, also inspected for possible leakage, repair or renewal.
Obviously this work can be done with greater ease and confidence that all is well if the top half of the smoke box can be removed, and this idea was introduced by one of our old-time members of the Golden Gate Live Steamers, Walter Brown. Friend Walter has built several beautiful steam engines and a number of years ago it occurred to him that it would be far easier to install and check the "plumbing" in the front end by splitting the smokebox and making the top half removable. A glance at the sketch is sufficient, I believe, to sell the idea to live steam loco builders particularly if building small boiler engines, that is, with front ends of 3", 4" and 5" diameters. However, it may be a little more costly as far as material is concerned as it is usually necessary to obtain twice the length of tube to make up for the amount taken out by the saw cut. In other words if a smoke box is being made of a piece of brass or steel tube 5" diameter and is to be 6" long, a piece of tube 12" long is needed, so as to obtain two complete halves.
The bottom half can be fastened to the cylinder saddle in the usual way, however, in order to provide for the fitting and fastening of the top half, two rings may be riveted to the bottom half to which the top half is held in place by two or more screws located at the top of the top half portion.
The sketch shows a method of joining the smoke box and boiler by using a stepped ring to take the lagging.