The Traveling Engineers Association | Page 9

a superheater
locomotive?
A. The supply of oil to steam chest should be watched very closely by
the engineer, he to know that lubricator is feeding constantly and
evenly over entire division, and according to work performed.
15. Q. Describe the general form of a locomotive boiler.

A. A locomotive boiler is cylindrical in form, it usually has a
rectangular shaped fire-box at one end and a smoke-box at the other,
and flues extend through the cylindrical part, and, like the fire-box, are
surrounded by water.
16. Q. How does the wide fire-box type of boiler differ from the
ordinary boiler, and what are its advantages?
A. The wide fire-box type of boiler is built so the fire-box is above the
frame and extends out over the driving wheels. The advantages of this
are to obtain a larger grate area in the same length of fire-box and to
give a slower rate of combustion per square foot of grate surface. The
deep fire-box is limited in width to the distance between the frames,
while the shallow fire-box sets on top of the frames and between the
driving wheels.
17. Q. Why have two fire-box doors been placed in the large type of
locomotive boilers?
A. For convenience of the fireman on account of the greater width of
the fire-box, so that coal can easily be distributed to all parts of the
fire-box.
18. Q. Describe a locomotive fire-box.
A. The modern form is a rectangular shaped structure located at the
back end of the boiler. It has a door and is composed of two side sheets,
a crown sheet, a back sheet and a flue sheet from which the flues
extend to the smoke-box at the other end of the boiler.
19. Q. To what strains is a fire-box subjected?
A. To crushing strains and to those of unequal contraction and
expansion.
20. Q. How are the sheets of a fire-box supported?
A. They are supported by staybolts screwed through the inside and

outside sheets with their ends riveted over.
21. Q. In what manner is a crown sheet supported?
A. By crown bars or radial staybolts.
22. Q. What are the bad features about crown bars?
A. They are hard to keep clean and frequently cause crown sheets to
become mud burned.
23. Q. What are the advantages of radial stayed crown sheets?
A. They are easier to keep clean and cheaper to repair.
24. Q. How are the inside and outside sheets of a fire-box secured at the
bottom?
A. They are riveted to a wrought iron ring called a mud-ring.
25. Q. Describe the ash-pan and its use.
A. It is a receptacle secured to the fire-box and usually provided with
dampers to regulate the flow of air to the fire. It collects the ashes that
drop from the fire-box and prevents them from setting fire to bridges or
other property along the track. Engine-men must know that ash-pan
slide and hopper bottoms are closed before leaving enginehouse.
26. Q. What is a "wagon-top" boiler?
A. It is a boiler that has the fire-box end made larger than the
cylindrical part to provide more steam space.
27. Q. Why are boilers provided with steam domes?
A. To furnish more steam space and to obtain dryer steam and to
provide a place for the safety valves, steam pipes, throttle valve and
whistle.

28. Q. What must be the condition of a boiler to give the best results?
A. It must have good circulation and be clean and free from mud or
scale.
29. Q. What is meant by "circulation" in a boiler?
A. Free movement of the water, so that it may come in contact with the
heating surface and after being converted into steam be immediately
replaced by a fresh supply of water.
30. Q. What would be the effect if a "leg" of the fire-box became filled
with mud?
A. There would be no water in contact with the fire-box sheets and they
would quickly become overheated and mud-burned.
31. Q. What would be the result if the fire-box sheets became
overheated?
A. They would be weakened and forced off the staybolts and an
explosion would occur.
32. Q. Would it be advisable to put water into a boiler after the sheets
had become bare and red hot?
A. No. The fire should be killed at once.
33. Q. What effect has the stoppage of a large number of flues?
A. The heating surface and draft are decreased by just that much area.
34. Q. Why are boiler checks placed so far away from the fire-box?
A. To introduce the water into the boiler at as great a distance from the
fire-box as possible. This permits the water to become heated to a high
temperature before it comes in