ort all defects noticed so plainly that they can be located by
the repair man without unnecessary work and whether there is steam in
the boiler or not at the time repairs are to be made. If the engine
blows, make a test to locate the blow and report it correctly. Also
report any unusual feature in the operation of the engine during the
trip.

=COMPOUND LOCOMOTIVES=

1. Q. Wherein do compound locomotives differ from ordinary or simple
ones?

A. Simple engines take live steam from the boiler and after one
expansion in a single cylinder it is exhausted to the atmosphere. A
compound engine has two cylinders, sometimes one on each side of the
locomotive; other types have four cylinders or two on each side of the
locomotive. The live steam first passes into one cylinder, expanding
down for a portion of its pressure, and then being allowed to pass into
the second cylinder where it expands a second time, thus getting two
expansions from each volume of live steam. Both simple and compound
locomotives consist of two engines coupled to the same set of driving
wheels. Balanced compounds have four sets of main rods and crank pins.
Mallet compounds have two complete sets of engines under one boiler.

2. Q. Why is one cylinder on a compound locomotive called the
high-pressure cylinder and the other one a low-pressure cylinder?

A. The high-pressure cylinder takes that name because it works live
steam direct from the boiler at high pressure. The low-pressure cylinder
receives the steam after the first expansion and works with a low
pressure. It is always larger than its companion high-pressure cylinder
in order to get the same power from the low-pressure steam.

3. Q. In the Schenectady two-cylinder compound, what is the duty of the
oil dash-pot?

A. It is intended to prevent the too rapid movement of the intercepting
valve which might damage the valve or seat, and it is necessary that the
dash-pot should be full of oil to make it work properly.

4. Q. Explain how a Schenectady two-cylinder compound may be operated as
a simple engine.

A. To operate the compound as a simple engine, the separate exhaust
valve is opened which will cause the intercepting valve to move and stay
in position to allow the high-pressure cylinder to exhaust direct to the
atmosphere and admits live steam at a reduced pressure to the
low-pressure cylinder. This should be done when starting a train or when
moving very slowly and about to stall