The sub compact small in .45 does have a rail. The module for 9mm, .40 and .357 does not. Sig seems to have lost interest in supplying grip modules they already should have available, I don't know if you'll see an sc with a rail, but I don't think I'll be able to buy a compact small 9mm module in my life time. Since I can't get the compact small I'm using the sub compact small with the 12 rounld mag and a 21 round mag with the x grip adapter as an extra. I have a Surefire XC1 on the medium compact module that came with the gun and would also like a railed 9mm sub compact.