When the Engine is highest on an inclined plane, rather a greater height of water must be kept over the fire-box than on a level, 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.