An upright piano main action rail with a special cross sectional shape of its lower half that angles or curves towards the back of the piano to effectively relocate the lower front surface of upright piano main action rail from a position in front of the row of whippen flanges as with the prior art to a relocated new position behind the row of whippen flanges to enable the front mounting of whippen flanges to the main action rail. Upright piano main action rail has all whippen mounting holes located its the lower front surface instead of the lower rear surface as with prior art upright piano main action rails.