The rail should work fine as part of the mesh if it's just a sawtooth. Usually I'm not opposed to increasing polygon counts (these are not the days of 2000-triangle battleships) but that looks like a lot of mesh for something people won't really see much. Just using a sawtooth will be six tris per bump or twelve tris per bump if they're angled at the sides as well.
edit, later: You can probably keep the rail as is based on the apparent whole triangle count of the model being around 2500 according to p3d.
