6. Improvements to the railroad began soon after it opened
Each of the ten engine sheds which stood at the tops of the inclines contained a single steam engine when the system opened. Within a year most contained two. The additional engines allowed the railroad to continue operation when engines were down for maintenance or repair. Improved engines were also added to the system over time. The single biggest improvement to the railroad over its more than two decades of operation came in the early 1840s. John Roebling observed the weakest link in the chain of systems which comprised the railroad was the hemp rope used to pull the cars. Roebling applied a theory he learned while in his native Germany to the problem.
He designed a rope made of twisted metal wires, which proved in experiments to be more durable and stronger than hemp. In 1842 he installed one of his wire ropes on incline 3, and its success led to a contract to replace all the hemp ropes within the system. He created a company to manufacture the wire ropes, and turned his attention to other uses for his products. They included safer ways of moving trams filled with ore in mines, and most importantly to Roebling, the construction of suspension bridges. The wire ropes on the Allegheny Portage Rail Road led to other improvements, including moving the canal boats themselves across the mountain, negating the need to offload passengers and cargo into railcars.