_Answer._ In pushing and switching the freight cars in the station-yard, they should be moved carefully and severe shocks must be avoided, as the cars, the goods with which they are loaded and the persons employed about them may be injured by violent concussions. The runner must also follow the instructions of his superior _strictly_ and _cheerfully_, and should examine patiently and observe with discretion the suggestions of employes who are not his superiors. In this service it is also of special importance that the runner give a _distinct_ signal with the whistle or bell before every movement of his engine, in order to warn in time those who at such times often stand on the track in the way of the engine or cars, or the persons engaged in loading, cleaning or repairing the cars, and thus give them time to get out of the way.[112] [112] Georg Kosak. QUESTION 493. _In firing a locomotive, what are the most important ends to be attained?_ _Answer._ That which is of first and chief importance is to make steam enough, so that the locomotive can pull its train and “_make time_”[113]; second, it must make the requisite quantity of steam with the least consumption of coal, and third, with the least production of smoke, although the latter, independent of the economy of combustion, is considered of importance only with passenger trains. What is frequently lost sight of in considering this subject is the fact that with all locomotives it often happens that it is a matter of extreme difficulty to make enough steam to do the work required of the engines. When a freight train is struggling up a grade with a heavy train, or an express engine is obliged to make time under similar conditions, it often depends entirely upon the quantity of steam which can be generated in the boiler in a given time whether the engine will fail or not. In firing, therefore, the most important end to be aimed at is often simply to produce the largest amount of steam possible in a given time, even at the sacrifice of economy or by producing any quantity of smoke. Any means of economizing fuel or of smoke prevention, which reduces the steam-producing capacity of boilers, is therefore quite sure to be abandoned in time. [113] The term _make time_ means to run at the speed indicated on the time-table. QUESTION 494. _How can a boiler be made to produce the largest quantity of steam in a given time?_