The Traveling Engineers Association | Page 5

to feed the fire again if a short stop is to be made until the train is
started and the engine cut back or nearly to the running cut-off.
40. Q. How should you build up the fire when at stations in order to
avoid black smoke?
A. Put in small quantities of coal at a time, have the door slightly open
and have the blower on lightly; good judgment must be exercised by
the fireman.
41. Q. Why is it that if there is a thin fire with a hole in it the steam
pressure will fall at once?

A. Because too much cold air is drawn into the fire-box and through the
tubes, retarding combustion and cooling the fire-box and tubes.
42. Q. If the injector is to be used after throttle is shut off, how should
the fire be maintained?
A. A sufficient quantity of coal should be placed on the grates to
maintain the maximum steam pressure and the blower used to keep the
fire burning brightly.
43. Q. What would be the result of starting a heavy train or allowing
drivers to slip with the fire too thin on the grates?
A. The fire would be pulled off the grates and into the tubes, leaving
the fire bed full of holes and some of the fire remaining on the grates
turned over. Large quantities of cold air would be drawn in, resulting in
a rapid decrease of temperature and pressure. The tubes would possibly
start leaking and the fire would be in such condition that it could not be
built up properly in a long distance. Possibly the grates would become
clogged up with green coal--an excellent opportunity for forming
clinkers. In this condition, the engine would fail to make steam for the
entire trip.
44. Q. Where should the coal, as a rule, be placed in the fire-box?
A. As a rule, more coal is burned along the sides and in the corners than
in the middle of the grates; the fire should consequently be kept
somewhat heavier along the sides and corners than in the middle.
45. Q. How is the fire affected by and what causes clinkers?
A. A clinker shuts off area of grate surface according to its size, and
thereby shutting off that much of the air supply and interfering with
proper combustion. Clinkers are caused by firing too heavy in spots,
which prevents sufficient air passing up through these spots and allows
the coal to run together, melting the ash, and sand; running a hoe or
slash bar through the fire will bring the points of melted sand together,
thereby causing a clinker.

46. Q. How can you best avoid their formation and dispose of them?
A. Light firing and occasionally moving the grates lightly is the best
preventive. When once formed, they should be removed if possible by
firing around and burning them out.
47. Q. How can you explain the slower burning of the coke and how
understand the proper manner of supplying fresh coal?
A. The gases of coal are lighter than air and will pass away whether
consumed or not. The slow burning of the coke is due to the fact that it
burns from the outside only. When a fire reaches a white or
incandescent heat it indicates that the gases are burned and a fresh
supply of coal should be added; this is to be done as light as the service
performed by the engine will permit.
48. Q. When and for what purpose is the use of a rake on the fire bed
allowable?
A. The rake should be used on the fire very seldom, because raking the
fire bed tends to form clinkers, especially when the rake is plunged
down through the fire to the grate. It may be used when necessary to
rake the fire lightly when on the road for the purpose of breaking the
crust, which may be found as a consequence of too heavy firing.
49. Q. Within what limits may steam pressure be allowed to vary, and
why?
A. Pressure should not be allowed to vary more than five pounds from
the maximum for the reason that too much expansion and contraction
will take place, which many times is the cause of flues leaking, cracked
or broken side sheets and stay bolts.
50. Q. Has improper firing any tendency to cause the tubes to leak?
How?
A. Yes; if the pressure is not regularly maintained, the fluctuations of
temperature cause constant contraction and expansion to take place. If

the fire is not carried level, but is carried heavy in some parts of the
fire-box and light in others, holes will be worked in, cold air drawn
through, lowering the temperature, chilling the tubes and causing leaks.
Carrying the fire