In 2014, one of these railroads became washed up in the tide. Those tracks were used for transporting munitions during World War I.
Closer to my home, there exist a set of beach tracks as well that were used in the south end of Illinois Beach State Park. While the tracks are currently buried under sand and snow, the right-of-way is generally still preserved in the area, despite the tracks having been torn up and made into a road not long after 1902.
A bit of history on the park. It’s location next to Lake Michigan prevented it from ever being exposed to the rampant development that encompasses most of the Chicago area, however a town was platted in the area, to be called Mayville. During both World War I and World War II, the US Army used the north end of the park as a basic training facility. It should be noted that as of this time the north end of the park was still not part of Illinois Beach, and wouldn’t be annexed by the rest of the park until the 1970’s. (Chrzastowski & Frankie)
Today, the ROW of the former railroad encompasses a majority of Illinois Beach State Park Rd before turning to the south and ending in the sand. No trace of the abandonment exists, at least at the moment, it is possible that the tracks wash up again. That being said, there are a few examples in the park of where one can visually see where the tracks went.
Source: Chrzastowski, M. J., & Frankie, W. T. (2000). Guide to the geology of Illinois Beach State Park and the Zion beach-ridge plain, Lake County, Illinois. doi:https://www.ideals.illinois.edu/bitstream/handle/2142/44512/guidetogeologyof2000chrz.pdf?sequence=2