Was standard railroad gauge (4’8-1/2”) determined by Roman chariot ruts?

Cecil’s column.

I quote:

17 summers have gone by with the length of 17 winters so I’m wondering. Did the Professor ever provide a cite? I’d love to know as I too have never read of such an edict by Caesar.

Just to add that tracks are 9 mm apart in N-guage model railroading … I knew you were curious …

How far apart were double trackways before the horse? … how close can two burdened humans pass each other comfortably? … in other words, did Caesar dream up 4’ 8-1/2" or was this already a long established separation? …