The ATS was superseded by ATS back in February 2021. Thus ATS is no longer required to go 90 MPH. It actually added more territory that Amtrak can go 90 MPH. When CTC was added to the Transcon, ATS was only installed in one direction where it was previously under Double Track-ABS. For example, Main 2 would have ATS only for eastbounds and Main 1 only for westbounds. Now, for the most part, any track that was good for 90 MPH is one direction is go in the other direction as well.

One little side note. Due to limitations with the overspeed systems on the Amtrak P42, ATS has to be cut-in to exceed 79 MPH. Thus, even with ATS gone on the track itself, the locomotive has to have ATS cut-in and working to go 90 MPH. It the locomotive's ATS failed, then it must be limited to 79 MPH. It will probably get corrected shorter or later.