Why?
- The ability of player-driven trains to reverse is contrary to everything else in the rail network:
- Train-stops show arrows when moused over,
- train signals show arrows when moused over and only affect trains travelling in one direction, and
- automatic trains can only go in one direction.
- It would make for a smoother transition to automatic trains, since
- the player would already be building turn-around tracks, and
- it matches the rest of how the rail system works.
(I haven't been able to find this particular feature request in any way, shape, or form, so maybe it is controversial. :)