Abstract: An extruded recording sensor mounting rail for keyboard operated musical instruments, particularly electronic player pianos, which can be used to install recording sensors in a new or existing piano. First and second flanges extend longitudinally along the front and rear of the mounting rail, and a shelf is provided on each flange, with the shelves configured for receiving and supporting a circuit board in a sensor assembly. Each flange includes an outward facing lip which extends longitudinally along the flange. One or more clips each include flanges which fit over the outward facing lips and retain the sensor board on the mounting rail.