Leo has already posted about CA. Some don't like to use CA because it can get brittle with age and railings can pop off with changes in the weather, etc.

I mostly use Gator's Grip Acrylic glue:

https://squadron.com/modeling-supplies/glue/?Brand=Gator__Grip&filterPage=1

It's a PVA glue and doesn't dry as quickly as CA and gives you more working time. If you're using it with a decent length of rail, you can use small pieces of masking tape to hold the rail in place and run a bead of it down the inside of the rail, then just remove the tape when the glue is dry.


If I'm going to use CA because I want something to set fast, I use Gorilla Glue Super Glue. It's not formulated the same as regular CA and doesn't dry as brittle, so it has more give in it for expansion/contraction due to weather.

There are also some specially formulated glues out there strictly for PE, but I haven't even used them (Just do a google search for photo etch glue and you'll find them) so I can't speak to how well they work.

HTH

Steve