It's my understanding that FT doesn't "provide" a rail with the track saws.
The dealers "package" an FS1400 in their marketing material, but it's really a saw at $xxx, and a rail at $xxx combined for the price. You could place any FS rail into the "package" that you like, or even buy the saw without a rail. In effect , making the 1900mm standard if you liked.
Perhaps [member=5]Bob Marino[/member] , or [member=48572]Shane Holland[/member] could chime in with the actual info ?