This folder is where all your downloaded Steam Workshop content is in its original .zip form, before being expanded by Railworks into the Content folder where the routes and scenarios reside.
Since Railworks unzipper appears to be flawed, I copy all the .zip files over to a safe storage.
However, does Steam or Railworks ever empty the 24010 folder? Mine contains over 3K subfolders dating back to 2016, probably all the Workshop content I've ever subscribed to ....
Keeping double storage of over 5 GB of files seems a bit redundant.