A whole train made up of nothing but cars loaded with coal is called a
black snake. Since rain and snow won’t hurt coal, it travels in cars
without tops. One kind of coal car has sloping ends like the one on this
page. It is called a hopper car. You load the coal in at the top, but
you unload it by opening trapdoors in the bottom which let the coal drop
into chutes.
Coal also travels in gondolas, which are just square-ended bins on
wheels. They have to be unloaded by hand or by a dumping machine. It is
hard to believe how fast some of these machines work. First a switch
engine pushes the car of coal onto a platform underneath a tower.
Grippers hold the car tight while it is jerked up, tilted over on its
side, dumped, then let down again empty. The whole job takes only a
minute or a minute and a half. The empty car rolls away downhill while a
full one is being switched into place.
[Illustration]
Another kind of dumper, the one you can see in the picture, looks rather
like a barrel that can roll from side to side. It, too, tips the car
over on its side so the coal can run out into a chute. Then the machine
swings back and lets the car drift downhill.
Locomotives and shops use almost a fourth of all the coal the railroads
haul. It takes much less coal now to run an engine than it used to take,
because engineers and scientists have thought up ways to make
locomotives better and better. They figure things so closely they can
even tell how much it costs to blow an engine’s whistle--three toots for
a penny.
Other things besides coal are often carried in hoppers and gondolas. Ore
travels from mines to mills in hoppers. Gondolas haul lumber.
[Illustration]
Things such as sugar and chemicals are sometimes carried in covered
hopper cars. Of course, these hoppers have tight lids and special
linings, and they’re kept very clean, so you won’t find coal dust mixed
with your candy.
[Illustration]