(Preble County, OH)--The permanent closure of several railroad crossings in Preble County has begun. On Thursday, the last vehicles ever crossed the tracks on Conley and Daily Roads. Now, Norfolk and Southern has permanently closed those crossings to install a second set of tracks. Still to come is the closing of the much more heavily traveled Oxford-Gettysburg Road between State Route 122 and U.S. 35. Hundreds of vehicles use that stretch of road every day. That includes National Trail School buses, which will now see their travel times significantly expanded.