It should be understood that in a well-organized works three or four orders, each for a dozen to twenty engines, are in hand at the same time. Thus the first order will be in course of completion in the erecting shop, whilst the boiler, fitting, and machine shops are dealing with the parts for No. 2 order. The forge and foundry and part of the boiler shop have in hand at the same time the forgings, castings, and boiler plates for the third order, and work may also have been begun in the pattern and template shops on order No. 4.
The Tender. Although the tender is constructed and erected in a separate tender shop, it may conveniently be considered here. The frame plates are of the same quality of steel as those of the engine, their thickness, about ⅞ in., being slightly less than that of the engine frames. There are usually four frame plates, which are marked off to templates, drilled, and erected with the necessary cross stays in a similar manner to those of the locomotive.
The wheels, axles, axleboxes, hornblocks and springs are also made in a similar manner, the chief difference being that the wheels, being smaller, do not require wheel lathes with such large faceplates. The wheels are simply pressed on to the axles by hydraulic pressure, and are not secured by keys, as are the coupled wheels of the locomotive.
The tank is a separate structure which is placed
