Rather than barely hang hangars on the wide metal rail that serves as a runner for the glass doors on our shower, I made this double-hook.
The photo shows four generations of the design.
It prints pretty easily provided that good adhesion is obtained. I use ABS glue and that works well.
Use two shells and 25% infill for strength. The final design is made to hug the contours of the rail so that it doesn't tip when one hook is used. Tweak for your rail dimensions and quirks.