What’s that strange-looking building on top of the bridge tower near Chickamauga Dam?

Ever been driving around, seen a building or some other structure and thought, “What the heck is that?” From the weird to the confusing, places like that dot the landscape of Chattanooga, and each has a story or an explanation. Here’s just one befuddling example.

A Dam Sight

The story of that mysterious little building way up high

For some parents, Chattanooga’s small house up in the air has been a valuable warning.

“When I was little, my parents told me that’s where they were going to put me if I was being bad,” Bike Voucher writes in a Reddit thread.

That’s a scary thought. Sitting on top of a tower more than 100 feet tall, the building — complete with windows and a door — sits just west of the Chickamauga Dam on the Tennessee River, right next to a bridge crossed by two railroad tracks. Many have wondered “What is that house?” over the years. Some theories on who lives there include a witch and a bridge troll (although everyone knows trolls live under bridges, not above).

But actually, no one ever lived there. It’s not a home.

“That structure is the machine house for Tenbridge, the vertical-lift railroad bridge over the river,” explains Heather Garcia, senior communications manager for Norfolk Southern Railway, which operates the tracks. “It is where we would operate the machinery to open and close the bridge when it needed to open.”

Years ago, when tall ships would pass through the dam’s lock, the entire center section of the bridge would raise up to allow the ships to pass under. In those days, an operator was stationed in the house-like structure on the tower to operate the machinery when a ship was coming through.

The original bridge was built in 1880, but the machinery house was added in 1920 when the bridge was changed from a “swing span,” where the mid-section of the bridge would swing on a pivot to open a passageway for tall ships.

These days, since tall ships very rarely use the Tennessee River anymore, the machinery in the house is only used a couple of times a year to raise and lower the bridge to make sure it’s still working in case the need arises.