Page:Locomotive performance; the result of a series of researches conducted by the engineering laboratory of Purdue University (IA cu31924004619502).pdf/35

 While the draw-bar was the only active agent by which the horizontal movement of the locomotive was controlled, there was ample provision of chains and buffers to check any excessive movement which might occur.

Above the levers of the dynamometer a floor was laid which chiefly served the purposes of a tender. It gave room for the storage of a limited quantity of coal, and for a tank from which the locomotive injectors drew their supply. Connected with the water-tank was a glass gauge, I, and above the tank a weighing-barrel through which the tank received its supply, Scales for weighing fuel were also given a place on the "tender floor."

The three counters at J were connected, respectively, with the rear driving-axle and with each of the two supporting shafts. These gave a ready means for determining the speed of the engine, and the per cent of slip between the drivers and their supporting wheels.

The telltale at K showed the position of the locomotive relative to the supporting wheels, The board a was fastened to the locomotive and consequently moved with it; the rod b was connected at one end, c, to an iron column as a fixed point, and at the other end to the pointer d. This pointer was pivoted to the board a at c, so that any backward or forward movement of the locomotive was greatly multiplied in the similar movement of the lower end of the pointer d.

A tangent-wheel and screw were provided at L for the purpose of turning by hand the forward supporting axle and hence the engine. whenever it might be desired to do so, as, for example, for convenience in valve-setting. When not in use, the screw could be disengaged.

The truck-wheels of the engine rested upon light rails which were fixed at the level of the laboratory floor and extended in front of the engine a distance sufficient to allow the whole machine to be moved forward off the supporting wheels, whenever the latter needed to be take out for repairs.

A Sturtevant 4½ X 6¾ steam-blower, located above the engine (Figs. 6 and 8) but not in pipe connection with it, removed from the room everything given out by the locomotive stack, without changing, materially, the draft conditions under which the locomotive worked.

The cylinder-cocks and the overflow-pipes from the injectors