Railroad or Center Zipper

The railroad, or centered, zipper application is the application most commonly used. It is used in center-front or center-back seams at a neckline or waistline. The stitching is visible on both sides of the zipper and is an equal distance from the center.

With the basted seam method, you insert the zipper while the zipperseam allowance is sewn together with a basting stitch.

Baste stitch the seamline for the zipper opening. Press the seam allowance open.
Open the zipper and place the correct side of the zipper to the wrong side of the gament, with the zipper teeth against the based seamline. Pin in place.

Note: Home sewing patterns usually allow a 5/8-inch seam allowance for zippers. Industry patterns allow a 3/4 -inch to 1-inch seam allowance.
3.Starting from the top edge of the garment and 3/4inch away from the zipper teeth, stitch just beyond the bottom of the zipper.

4.With the needle down, lift the presser foot and pivot the garment...