WHAT ABOUT ALL THOSE FREIGHT TRAINS? - All Aboard: The Complete North American Train Travel Guide - page 201

and local railroads. Somewhere between 50,000 and 70,000
freight cars of all types are built every year to increase the size of
fleets and to replace cars that wear out and are scrapped.
The average freight train is about 70 cars long, and many
will have well over 100 cars in the consist. In terms of the phys-
ics involved, there is almost no limit to how many locomotives a
long freight train might be given. There are a number of practi-
cal considerations, however. Probably the most obvious is how
much of a train's capacity has been sold by the railroad's sales
department. But long freight trains can block busy city inter-
sections for a very long time and generate very serious public
relations problems. Extralong trains can even cause the railroad
itself problems if they block important switches in the rail yard.
As it is, freight trains run through many towns across the coun-
try. In many cases, those towns have to build and staff duplicate
police, fire, and ambulance facilities to make sure that one of
those emergency responders won't be delayed by having to wait
for a slow freight.
You'll see thousands of freight cars from the window of your
train. Part of what's interesting about a train ride is knowing
what all those cars are for and what's inside them. There is an
almost infinite variety of sizes and designs, but it all starts to take
shape if we break them down into a few simple categories.
Boxcars
This is what most of us mean when we say “freight car.” It's an
enclosed car with a roof and sliding doors on both sides. Boxcars
are used to carry a whole variety of general merchandise, par-
ticularly items that must be protected from the weather. If your
local hardware distributor orders 200 power lawn mowers from
a manufacturer, chances are those mowers rode across the coun-
try in one of these railroad cars.