Ungrindable Rail

At SCAF, the small tunnel doing downhill towards Stalefish Bevvie Co. - there is an ungrindable rail. 

I found that the rail dosent seem to have correct collision whilst on-board, since every time I jumped onto it, it either flung me off or bailed me into the ground. 

Attached is an image showing the staircase handrail that cannot be grinded.