Tank cars hold a unique place in the history of railroad
freight cars. The fledgling petroleum industry of the 19th Century needed
a way to transport their liquid product beyond the reach of pipelines.
As a need persists, invention is sure to follow; the petroleum companies,
at first, built their own
railroad tank cars simply by adding wooden tubs to flat cars. Even before
the turn of the century,
tank cars such as this Richfield Oil car were designed and manufactured
by the oil companies.
Tank cars are a common sight on today's railroad,
and are constructed to carry a variety of liquid commodities. The railroads
rarely supply special-use cars like tank cars to freight customers.
Unlike boxcars, tankers such as #670, could only carry one specific
kind of commodity from a specific company. Also, it is extremely difficult
to thoroughly clean out any residue left within a tank car. Privately-owned
tank cars were the first type of freight cars built for and owned by
or other shipper and just pulled from place to place by the railroads
for a fee. The "X" designation still seen today in a freight car's number
means that it is a car owned by a company other than the
railroad. The "ROX" on this car, for example, means it was the property
of Richfield Oil, regardless of
the railroad on which it might have been running.