The massive De La Vergne engine, once one of the smaller steam engines in the refrigeration plant at Armour, is now the largest, as its larger counterparts are long gone. First you can see photos from June 1986, and then photos from the present day. The machine created refrigeration for the coolers in the adjacent buildings. More about the engine can be read here.
All photos from 1986 courtesy of Dennis Bensheimer.
The De La Vergne engine company has an interesting history, which you can read here. Founded in 1880, it provided refrigeration units for several St. Louis companies besides Armour, including Anheuser-Busch in 1892. In fact, if you look at the two engines from the respective plants, they are remarkably similar in appearance, though the A-B unit was apparently larger.
The rest of the photos were taken in the last five years at Armour.
The pit seen in the two photos next to the De La Vergne steam engine below makes me wonder; was this the location of another of the giant steam engines? Perhaps the pit held the flywheel?
As can be seen in the more recent photos, the insulation has begun to fall off in large clumps from the pipes. Interestingly, and mysteriously, Mr. Bensheimer said that some of the refrigeration units were definitely running on electrical power back in 1986; for what purpose, we do not know.
Update: Demolished by implosion in April 2016.