Cincinnati's Dormant Giants: The World's Largest Steam Engines

In the early days of indoor plumbing, the task of supplying hundreds of thousands of people with water in swelling cities was a monumental task. For a city to grow it needed to be able to moisten its teeming masses, as well as supply water to industry. Municipal engineers all over the country were scrambling to build water systems to keep up with the demand of sprawling populations.

Cincinnati chose to handle its growing demand dramatically. Rather than slowly cobbling a system together, Cincinnati built one gargantuan pumping station that would be plenty large to supply the city for decades. It was to be called River Station, and would pull from the delicious waters of the Ohio River. But to do so would require building the four largest steam engines in the world to power the pumps. In the end they would stand a towering 104 feet tall and pump 30,000,000 gallons of water every 24 hours. 

Construction began in earnest in 1898, but difficulties plagued construction. The engine house and coal shed had to be high enough above the river to be out of flood range, but also needed to be below the water table of the river to have access to a consistent supply of water, using natural water pressure to feed the pumps. This required digging the pump house 85 feet deep, putting its floor 5.5 feet below the bed of the Ohio River. The excavation had to be performed by manual labor and fairly primitive steam driven excavation tools.

Each of the steam engines weighed in at 1400 tons, and had to be aligned to within 1/100 of an inch. If the floor shifted even 1/8 of an inch, the engines would not be able to function properly. This installation proved to be especially complicated, as they were unable to rest the protective chamber that would hold the engines on solid bedrock. The floor of the engine house fluctuated in height due to hydraulic pressure from the river and swelling of the oak pilings when they became water logged. In order to stabilize the platform, a ballast was made by strategically placing engine parts around the floor then adding 35 feet of water on top of that. The ballast weighed 13,000 tons total. After two months the floor was deemed stable, the water and engine parts were hauled out, and the assembly of the four engines began.

During construction water had to be pumped into and out of the pit to compensate for the rising and falling water levels of the river (a practice occasionally used to this day). In August of 1905 the engines were hastily assembled to counteract the rising winter water levels, which could have resulted in the floor shifting again, then completely disassembled and reassembled properly once the water levels fell. Slowly the engines came to life. By August of 1906 all four were online.

The engine house that sits over the pit is a round romanesque revival stye building with rail car access to the engine room. An elevator and two spiral staircases provide access to the engine's 11 service platforms. A large overhead crane is used for working on the engines or for starting them in instances when the engine was not shut down properly. If the engine was stopped at the top of its stroke, it couldn't be restarted. In such an instance, the crane would lower a rope to one of the engine's two 24 foot tall, 40 ton flywheels. The rope would be tied to the flywheel and used to pull the engine into the correct starting position. Two workers would be present with axes to cut the rope free as soon as the engine rolled over. Every major part of the engine was designed to be accessible by the crane without requiring other machinery to be disturbed to service or remove it. Even the teeth on the gears that drove the cam shaft were individual pieces made of hardwood, allowing for speedy replacement.

Massive amounts of fuel were needed to power the boilers that fed the engines steam. Coal was delivered to the engine house by rail. An elevated coal shed housed 114 hoppers, each of these holding 7,980 pounds of coal, 70 tons all together. A 175 foot smoke stack was constructed for the boiler house. Early on, a bolt of lightning hit the chimney, superheating moisture that the bricks had absorbed from the steam and causing some of them to explode. The chimney was repaired, this time with a lighting rod.

The tertiary equipment in place was also remarkable. The facility was equipped with a small electric locomotive system, 17 other steam engines performing other duties, an array of huge boilers to supply steam, a water filtration system, a coal delivery conveyor belt system, and a machine shop. Altogether a daily staff of 36 operated the river station, from oilers to clerks.

The enormous engines remained active until December of 1952 when they were deemed outmoded and replaced by electric motors. Due to the scale of the engines, they were never destroyed. Volunteers are currently investigating the possibility of running the engines again, but for the time being they sit silent, the boilers that once provided their steam scrapped long ago. Although they no longer run, they still remain the worlds largest steam engines. If you're ever in town, stop by for a tour!