Why are ore cars so short? Because the iron ore they carry
is considerably heavier than typical hopper loads like coal, so a short car of
ore fills the load capacity of its trucks. Ore cars, also called “jennies,”
were and still are a common sight in the Iron Range region of Minnesota and
nearby states, where they shuttle between mines and Great Lakes ports. On the
receiving end, jennies travel between ore docks and steel mills in a number of
states. While they’re commonly associated with upper Midwestern ore-hauling
roads, ore cars have in fact been rostered by nearly 50 North American
railroads, and at least a dozen have owned significant numbers of jennies.
Until World War II, ore cars generally carried “direct shipping” ore: ore that
was rich enough in iron (60% or more) that it could be shipped direct to steel
mills as a raw material. By the end of the war, however, the richer ore
deposits had largely played out. Lower-grade taconite, once considered a waste
product of mining, became the raw material of choice. Rather than being shipped
as raw ore, taconite is refined and rolled into small pellets containing about
65% iron. So for more than half a century, the main payload of ore jennies has
been taconite pellets, as well as occasional loads of sand or gravel.
