Practical Rules for the Management of a Locomotive Engine: | Page 4

in order that the chimney ends of the tubes may be well covered.
The most favourable time for allowing the feed-pumps to act, is when the steam is blowing off with force from the safety-valve, and the fire strong; and the least favourable time is when the steam and fire are low: indeed the Engine-man should manage that it may never be necessary in the latter case, as the addition of water rapidly lowers the steam.
In order to know the force of the steam, one hand may occasionally lift or depress for a moment the lever of the safety-valve, according as the steam is under or over the working pressure; and a little practice will soon enable a person to judge the extent of excess or deficiency.
Both feed-pumps should not commence working at the same time.
The water should never be allowed to run low before arriving at any part of the road where considerable power is required, as steam is produced more rapidly when both pumps are turned off,--a measure which is imprudent unless the water is high.
When "the feed" is turned on, the Engine-man should try the pet-cock to see whether the pump is acting freely: the water thrown from it should be in forcible intermittent jets; warm water with a little steam will frequently escape from it at first; if this should continue, it may be concluded that the upper clack does not act; and if the water is in a continuous stream without pulsations, the lower clack is out of order. In either case it will not be prudent to trust too much to the faulty pump, but the evil may frequently be remedied by working the pump a short time with the pet-cock open, or alternately turned on and off.
Coke is put on the fire by the Stoker, at the order of the Engine-man, who should hold the chain of the fire-door in his hand, and open it for as short a time as possible, while the Stoker throws on each shovelful of coke: the shovel should be well filled, and the coke distributed equally over the fire.
In most Engines, the fuel need not be higher than the bottom of the fire-door; and if allowed to fall more than 6 or 8 inches below it, it must not be expected that the pressure of the steam will be maintained, if the Engine has a load.
The supply of fuel should be regular, and so arranged that the fire may have burned up well by the time the steam is most required. As the addition of fuel causes a temporary reduction of the force of the fire, coke should not be laid on immediately before arriving at an inclined plane or any part of the road where much power is required; but when ascending an incline, coke should be gradually added when the Engine begins to beat heavily,--the draught is then powerful, and a regular supply of fuel required to keep up the fire.
In other circumstances, provided the fire is low enough to require fuel, the best time to put on coke is when the water is sufficiently high to turn off the feed-pumps, the steam slightly blowing off, and the Engine travelling at a good speed.
No definite instructions can be given for the frequency with which coke must be laid on the fire, as it varies according to the duty to be done, and the water consequently to be evaporated: in cases of heavy duty and bad gradients, it may at times be necessary even at as short an interval as 2 miles; under contrary circumstances an Engine may sometimes run as much as 15 miles without adding fresh coke.
The fire should be allowed to run rather low before arriving at the top of an inclined plane down which the steam will not be used: on beginning to descend the plane, fuel should be put on the fire, which will burn up by the time the train reaches the bottom of the plane.
If it is wished to keep up the steam, it is better not to supply water and fuel at the same time.
While running, the Stoker should occasionally pick the ashes from the tubes to clear the draught.
By observing the above rules for the supply of water and coke, an efficient pressure and quantity of steam will be produced, which it must be the study of the Engine-man to economise. With this view the regulator should never be kept too far open;--as soon as the train has acquired the velocity wished, the aperture may be considerably reduced without diminishing the speed. As any diminution in the amount of steam used causes a corresponding diminution in the quantity of coke consumed, the skill of the Engine-man should be unceasingly directed to the reduction of so heavy an item