e a stop or a slow-down, the engineer closed down the throttle and
very gradually opened the air-brake valve that admitted compressed air
to the brake-cylinders, not only on the locomotive but on all the cars.
The speed of the train slackened steadily but without jar, until the
power of the compressed air clamped the brake-shoes on the wheels so
tightly that they were practically locked and the train was stopped. By
means of the air-brake the engineer had almost entire control of the
train. The pump that compresses the air is on the engine, and keeps the
pressure in the car and locomotive reservoirs automatically up to the
required standard.

Each stage of every trip of a train not a freight is carefully charted,
and the engineer is provided with a time-table that shows where his
train should be at a given time. It is a matter of pride with the
engineers of fast trains to keep close to their schedules, and their
good records depend largely on this running-time, but delays of various
kinds creep in, and in spite of their best efforts engineers are not
always able to make all their schedules. To arrive at their destinations
on time, therefore, certain sections must be covered in better than
schedule time, and then great skill is required to get the speed without
a sacrifice of comfort for the passenger.

To most travellers time is more valuable than money, and so everything
about a train is planned to facilitate rapid travelling. Almost every
part of a locomotive is controlled from the cab, which prevents
unnecessary stopping to correct defects; from his seat the engineer can
let the condensed water out of the cylinders; he can start a jet of
steam in the stack and create a draft through the fire-box; by the
pressure of a lever he is able to pour sand on a slippery track, or by
the manipulation of another lever a snow-scraper is let down from the
cowcatcher. The practised ear of a locomotive engineer often enables him
to discover defects in the working of his powerful machine, and he is
generally able, with the aid of various devices always on hand, to
prevent an increase of trouble without leaving the cab.

As explained above, a fast run means the use of a great deal of steam
and therefore water; indeed, the higher the speed the greater
consumption of water. Often the schedules do not allow time enough to
stop for water, and the consumption is so great that it is impossible to
carry enough to keep the engine going to t