I was curious to know, and if you are too, records of the Patent and Trademark Office show that the first patent was granted to John Ruggles of Thomaston, Maine for railroad traction wheels on July 28, 1836. According to Ruggles in U.S. Patent #1, he invented "a new and useful improvement or improvements on locomotive-engines used on railroads and common roads by which inclined planes and hills may be ascended and heavy loads drawn up the same with more facility and economy than heretofore, and by which the evil effects of frost, ice, snows, and mud on the rail causing the wheels to slide are obviated." In order to prevent sliding, Ruggles used a check rail and retreating cogs operated by springs on the rims of the locomotive wheels. His invention overcame the "evil effect of frost, ice, snow and mud" and enabled trains to travel more easily, an on-going effort that continues to this day.
It took 34 years before the 100,000th U.S. patent was granted. That too was transportation related as can be seen in the patent drawing below.
These days the U.S. Patent Office grants hundreds of thousands of patents per year.
