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.
Unlike conventional coal hoppers, the prototypes of our ore car, originally built in the 1940s and ‘50s, used a construction technique that would later revolutionize grain hoppers: eliminating the center sill that normally formed the basis of a freight car underframe, in favor of heavier side sills that supported the weight of the car. This made room for “center discharge” hopper doors positioned lengthwise under the car, to dump the load neatly between the rails at ore docks.
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 began to play out. Lower-grade taconite, once considered a waste product of mining, became the raw material of choice, and by the mid-1960s accounted for the majority of ore shipments. Rather than being shipped as raw ore, taconite is refined and rolled into small pellets containing about 65% iron. Because taconite pellets are lighter than direct shipping ore, many railroads have increased the interior volume of their jennies by adding short extensions to the tops of the cars.
Mini-Quad Sets were created by the DMIR to better manage the loss of air brake pressure between individual cars. These semi-permanent 4-car sets - connected by a bar between cars and a coupler on each end of the set - first appeared in 1972. When configured as individual cars by Pullman Standard in 1957, the U31 configuration sported numbers 33000 - 33499. When configured in mini-quad sets, the first number (3) of each car number was replaced with a 5.
M.T.H. Electric Trains' HO premium rolling stock like 70-ton center discharge ore car are true 1/87 scale models of North American freight cars. Abundantly detailed with separate grab irons, steps and brake wheels ensure that these models will hold up to even the most discrminating eye. Outfitted with smooth rolling trucks and Kadee couplers make them a favorite of operators who enjoy long consists of colorful liveries, each available in multiple car numbers.