Removing paint

You can also use CA or other non plastic cement type glues to attach your railings and not worry about scraping/remooving the paint at contact points.

Will CA glue make a strong enough bond to paint? have you tried it?

Yes I have tried it. CA glue has a very strong bond. As do acrylic glues like Gator Glue. The only real problem in either case of bonding to the paint is the paint type below. Some acrylics, Model Master in particular, have very poor adhesion to bare plastic below and the paint itself may give way if the part it bumped or knocked about. A good primer underneath will alleviate this problem.

I use Ca to attach all paint exterior tools/fittings on my tank models. It sticks well and due to the small amount needed is easy to hide.

As long as you do the railings late in the building, so the model will not be handled too much after the railings are done, they do not need to have super adhesion.  They weigh so little they are not susceptible to shock forces- usually only direct contact causes them to come loose.  And by like token, they do not stress the paint adhesion with any great force.  So I have found, unlike most gluing, I can get by with gluing them over paint. I often apply a few spots of gel CA just to keep them in position while I apply a 50:50 mix of water-thinned white glue.

One trick I use on gluing heavier parts on painted surfaces is to use a pinvise and small drill to drill a number of small dimples through the paint into underlying surface. This is usually enough to get a decent bond with high strength adhesives such as CA.