Beloved classic Counter-Strike map Train has been rebuilt from the ground up for Global Offensive. In addition to a graphical upgrade, the new Train map ushers in some "intuitive layout changes" and is available in the Operation Vanguard map group across a variety of game modes.
But what of these "intuitive layout changes"? The details can be perused over on this rather thorough blogpost, but whole sections of the map have been removed (such as the middle tunnel in the yard) while the bomb site has been shifted to another corner of the map.
Check out the video below for all the gory details. The map arrives as part of a new patch which is detailed here.