[Gpa113]

Missed this post yesterday. 

I repainted sand borders (and black track) to grey. 
Cleaned borders with industrial scale builders wipes, used an automotive primer, then painted with Ultra smooth masonry paint. 
No issues with paint lifting. 
Primer was possibly unnecessary? 
Borders are easier as you don't have to mask the rails!  

If I was just doing borders, then yeah, automotive spray paint would be my choice. 

Pip