How long does it take a typical tractor trailer to clear a single railroad track? A double track?

Railroad crossings with steep approaches can cause your unit to hang up on the tracks. Never permit traffic conditions to trap you in a position where you have to stop on the tracks. Be sure you can get all the way across the tracks before you start across. It takes a typical tractor-trailer unit at least 14 seconds to clear a single track and more than 15 seconds to clear a double track. Do not shift gears while crossing railroad tracks. [Commercial Driver Handbook]