Seems likely that safe access for maintenance makes this unappealing economically. Likely easier to have wider rail right of way and then put a panel farm on the side.

With the added benefit of being able to mount the tracks at an angle, and the added disadvantage of occupying area near the tracks that is occasionally used for maintenance equipment.

And getting approval to widen the right of way, where it’s even physically possible, and issues around flora suppression.