Pretty sure the reason they didn't go with the Fontana rail is because they race in winter, and that safety rail casts a pretty good shadow that might promote some sort of ice buildup on the shadowed portion of the track...or at least hinder ice melting...
At least that's what I remember the argument being back in the day...trade one safety issue for another...
Not sure what's changed in that regard, since I'm pretty sure they haven't altered the physical location of the track...
And I can't imagine the main track being in a better position sun-wise to use the Fontana rail compared to the now defunct inner track.
