thelt - I just saw this forum thread pop back up on the forum list, and I'm not sure if the question about split rail was for me. I'll go on a limb and think it is (not many other "pax's" on LJ, and I vaguely recall asking about the split rail).
For full disclosure, I don't OWN this saw, I only played with it in the store (I have a Dewalt DWE7491RS due to my space constraints, but regularly frequent other shops and use an older Delta Unisaw, or Sawstops). The split rail is the two piece front rail that the fence rides on. Others who have used the saw seem to note that if properly setup, it behaves nicely.
In regards to riving knives, all (new) saws sold in the US must have some form of riving knife thanks to the UL 987 regulations (
https://www.finewoodworking.com/workshop/article/tablesaws-under-siege.aspx), and I can confidently say that the Delta's guard can be set into a riving knife position. I haven't read the specs to see if the included guard/"riving knife" is spec'd for a thin (I suspect it's thin) or full kerf. The important thing to know, is that the knife needs to be (slightly) lower in thickness to the kerf of the blade used but thicker than the saw plate. Most thin (3/32) kerf blades will be fine with the riving knife, but blades, regardless of how good I've seen the full kerf version perform (i.e. Freud Premier Fusion TK), I wouldn't try (personal overkill safety preference, so take it well seasoned with salt) to use with my saw and riving knife, because the blade kerf is too close in thickness to the riving knife.
