Steam Locomotives, devices that would literally drive and power the American railroad
industry for its first 130+ years of existence actually has its origins
in England. Originally built by Richard Trevithick and Andrew Vivian in
1804 for the narrow gauge Penydarren tramway in Wales the contraption
was first tested in America in August of 1829 when Horatio Allen, a
chief engineer for the Delaware
& Hudson Canal Company (later the Delaware & Hudson Railway)
tested an early English steam locomotive design on a 16-mile stretch of
track the company owned between Honesdale and Carbondale, Pennsylvania.
The locomotive used was named the Stourbridge Lion, which was a very
simple two-axle machine with a vertical boiler, and it was employed to move coal from the mines at Carbondale to Honesdale.
Until the 20th century virtually all steam locomotives coal as their
primary fuel source (although very early locomotive designs, like 4-4-0
Americans used wood) with large tenders of water to produce the
necessary steam. The operations of steam locomotives are relatively
simple, which I will try to explain just briefly. Fuel, usually either coal
or oil, is fed into the firebox where the resulting hot gas enters
boiler tubes, known as flues, to heat the surrounding water turning it
unto steam. From this point the steam is fed into the pistons whereby it
expands and drives the steam locomotive’s rods (those massive steel
shafts which are attached to the wheels) and propels it forward.
The hot gases are then carried into the smoke box where they are
funneled into the smoke stack and out of the locomotive. A quick note
about the "modern" steam locomotive smoke stacks, most carry grating or
some other type of screening to help reduce the amount of cinders
(especially in the case when wood was used as fuel) which are projected
into the air and can cause brush fires. Coaling towers grew in size as needed with increasingly larger steam locomotives. Some of the first coaling towers were only a few stories tall and held less than 100 tons of coal
usually also only serving one track. However, as larger locomotives
like 4-6-2 Pacifics, 2-8-4 Berkshires and 4-8-4 Northerns were
introduced in the late 19th and early 20th centuries it was obviously
necessary to increase the tower's size.
The workings of a coaling towers
are relatively simple. They were always gravity fed with the steam
locomotive sitting below or nearby (if the tower employed chutes) and an
operator would feed coal into the tender until it was topped off. To refill the towers
they usually had a staging track or an area where loaded hopper cars
could be unloaded and a pulley/belt driven system would pick up the coal
and load the bin. Early systems were rudimentary using straight chain
and pulley buckets but later systems used conveyor belts to efficiently
load the coaling towers.
At their peak coaling towers were impressive structures standing
multiple stories high and looking more like massive grain bins one might
see out on the plains. They were also built of reinforced concrete and
either straddled multiple railroad tracks or used chutes to load as
many locomotives at once as was possible to achieve economies of scale.
Unfortunately, these newer coaling towers were so well built that many have proven too expensive for railroads to demolish and several can still be found dotting the landscape across the country, abandoned sentinels of a bygone era of railroading.
For more reading about coal and its relationship with the railroad industry consider the book Coal Trains: The History of Railroading and Coal in the United States
from authors Brian Solomon and Pat Yough. The book looks the
importance black diamonds have held within the industry, from fuel use
to its high profit value, especially today. You may also want to consider Perfecting the American Steam Locomotive by author J. Parker Lamb. As the name implies the book details the earliest history of steam engine
technology, even before it was used in railroad applications. His book
later explores the development of steam locomotive technology in the
United States from the 19th through the 20th centuries, covering not
only the most popular steam locomotive designs but also the most
successful manufactures to build them.