I also wish Google well at data cleansing. Look at FRA's GIS online system and see how many grade crossings are in the middle of nowhere, incorrectly identified, etc. Yes, you can blame the railroad for some of that if they made mistakes when entering data, but in other cases it's just plain not keeping things up to date. There are also many other grade crossings that are NOT in FRA's system, mostly on industrial, transit, and "out of service" lines. In principle, this is a good idea; in practice, it's going to be a lot of work for somebody.