Ryobi table saw fence rails are unique in that they are designed to move quite easily. The problem is that most likely when they are moved, any fine-tuning alignment that has been done is lost. They will most likely be misaligned once they are repositioned. My recommendation is to put the rails where you want them, line them up, and never move them again.

The alignment of the rip fence rails is crucial to the overall alignment of the table saw. The rip fence and sliding miter table rely on the rip fence rails to be properly aligned.

What are we trying to achieve?

The rails are a uniform depth below the top of the table saw.
The rails are parallel to each other.
The rails are level with each other.
When they are misaligned, what effect does it have?
The sliding miter table should be at 90 degrees to the table saw blade. When the rails are out of alignment, the angle of the sliding miter table relative to the table saw blade will be greater than 90 degrees or less than 90 degrees. Either way, when using the sliding miter table, the cuts will not be square.

The rip fence will also not be at a 90 degree angle to the table saw base. The result will be material torn at an angle other than 90 degrees.

Alignment process

parallel rails

The rails are attached to the table through milled bosses. The rails should be parallel to each other, if normal care was taken when the unit was assembled. Use a ruler or tape measure to measure the distance between the rails at various points, at the far left, middle, and far right. If the rails are not parallel, the rail will need to be shimmed to make them parallel. It is better to chock the rear rail.

Uniform depth under the table

The challenge here is that the head table top is very narrow. It does not provide a very large surface to measure when checking the depth of the rails. To increase the size of the table top, attach a straight edge to the head table. This will provide a longer length to measure the depth of the rails.

If you have the extension rail kit, screw it to the main rails. Then do the depth alignment. If one of the rails is too high or low, loosen the mounting bolts on the table saw and extension leg. Adjust the rail height with the extension leg adjustment screw.