A rail, such as a head rail, for an architectural covering. The rail includes a housing having elongate walls extending along a length of the housing and defining therebetween a width of the housing. A drive shaft is rotatable about a drive axis extending along the length of the housing and is configured to wind and unwind lift cords of the architectural covering. A spring assist module, e.g. a spring motor has an output shaft rotatable about an output axis with rotation of the drive shaft. The spring motor is mounted in the housing with the output axis parallel to the drive axis, but offset from the drive axis with respect to the width of the housing and the output shaft is connected directly to the drive shaft for rotation therewith.