Which innovation had the greatest impact on availability of fresh beef us east coast by end 19th century?

The innovation that had the greatest impact on the availability of fresh beef on the US East Coast by the end of the 19th century was the refrigerated railroad car.

Here's why:

* Before refrigerated cars: Beef from the Midwest and West could only be shipped to the East Coast as salted or dried meat, which was much less palatable and nutritious than fresh meat. This limited the amount of beef available in the East and made it expensive.

* The impact of refrigerated cars: The invention of refrigerated cars in the 1860s and their widespread adoption in the 1870s revolutionized the meat industry. It allowed fresh beef to be shipped long distances without spoiling.

* Consequences: This dramatically increased the supply of fresh beef on the East Coast, making it more affordable and accessible to a larger population. It also contributed to the rise of large-scale meatpacking companies like Swift and Armour.

While other innovations like the development of the steam engine and the telegraph also played a role in the transportation of goods, the refrigerated railroad car was the key factor in making fresh beef a staple of the American diet by the end of the 19th century.