Mirroring
Edit → Mirror horizontally and Edit → Mirror vertically flip the plan over. Horizontal swaps left and right, vertical swaps top and bottom. Heights stay as they are.
Mirroring applies to the selection, or to the whole plan if nothing is selected. The axis sits at the center of whatever is being mirrored, so the plan stays where it is.
Select bound objects too
A pole or a signal only mirrors along if you select it together with the track.
A symmetric track plan
Duplicate one half and mirror the copy — faster than rebuilding it by hand.
What happens to the tracks
A track can't always simply be flipped: a left switch becomes a right switch in the mirror, and that's a different item. Raily therefore replaces each track with its counterpart wherever possible. The search is based on geometry; if there are several candidates, the most similar item number wins.
After mirroring, a message reports what happened: how many tracks were mirrored, how many became individual pieces for lack of a counterpart, and which could only be moved.
Tracks in a group
If an entire group is selected, it is only moved, not mirrored; the tracks inside keep their original orientation.