We are completing a major overhaul of our small,urban yard, L-shaped back yard and have run our G-Scale train around the yard, including through a tunnel under the waterfall. The yard is enclosed by concrete block. I would like to paint (actually have someone who is an artist) one section of wall where the track runs close by, with a railroad town, some scenery in the background. What type of paint would be appropriate and last? We are in southern CA with lots of sun on that section of wall.

Thank you.