There are several conditions for which the rust on the metal railing occurs. The most house hold problem is the paints that get removed through wear and tear from the railings. As the paint gets old it gets dried. Moisture gets through the cracking part and rusting process continues. The rust immediately attacks those bare places. More scratches more the railing will get prone to rust. Metal will get rusted anytime if it is not properly protected.

The metals that are used in building the railing are brushed to remove the rust and then welded together. Finally the whole substances are painted. If somehow you delay in the painting then the metals can start rusting. Basically the rust remains visible as they remain hidden in the pores of the metal which require a microscopic view to see. So naturally the metal gets painted. With time rust starts getting visible forcing off chips of paint. This can happen in few months after the railing is made.
To remove rust from metal and keep the freshness of the railing intact you have to remove the rust completely. In earlier days you have to remove the rust. Give priming and repainting. This is an expensive procedure and more important time consuming.

In present days people don’t have so much time to spend on removing the rust. But thanks to the latex based non toxic rust products available in the market. This solution when applied over the rust surface they neutralize the rust and prime the surface. Now finally a good paint is used to give a finishing tough. This will give a long term protection against rust.