In the 1840s, legendary British engineer Isambard Kingdom Brunel envisioned a revolutionary alternative to heavy steam locomotives for the hilly South Devon Railway: atmospheric power. Instead of carrying an engine, trains were pulled by a piston running inside a continuous iron pipe laid between the tracks. Stationary pumping stations created a vacuum ahead of the piston, pulling the train forward at impressive speeds reaching 60 miles per hour.
To keep the pipe airtight while allowing the connecting arm between the train and the internal piston to pass through, Brunel designed a continuous longitudinal slot sealed with flexible leather flaps held closed by grease and tallow. However, this innovative design harbored a fatal flaw. The tallow-soaked leather proved irresistibly delicious to the local rat population.
Rodents chewed through miles of the sealing flaps to eat the fat, causing catastrophic vacuum leaks that destroyed the system's efficiency. Combined with cold weather hardening the leather and salt spray deteriorating the iron, maintenance costs spiraled out of control. Less than a year after full operation began in September 1847, the atmospheric system was abandoned in September 1848, converting back to traditional steam power and costing the company over 400,000 pounds.