Palin Hill was a steady 3.7 percent grade. It was the original line into Guatemala City, connecting the capital with the world via Puerto San Jose on the Pacific coast.
One of the things I found fascinating about the IRCA is this original line was built by the Central Pacific syndicate based in San Francisco, with Collis P. Huntington the president. Cars came from Kimball Manufacturing Company in San Francisco, and the CP shops in Sacrament. It was originally built as a meter gauge line, and changed to three feet in 1890.