You can combine roads and rails to create an exploit that generates infinite building resources.
You do that by building any single road segment of any length, then building any single rail segment inside that road, but one grid point longer (See attached screenshots).
You can then delete the rail as often as you want and you will get the resources for deleting it every time. This bug basically fixes itself once you save and reload the save game (*temporarily, it can be re-activated by doing the same as described again).
Steps to reproduce:
