Real schedules would have disappeared when train orders did, since this was the authority the trains operated under outside of CTC authority. IIRC, the GCOR change about 1989 dropped train orders from the rules. Most RRs switched to TWC for non-CTC, but SP liked DTC (and had adapted the old manual block system to radio for the Cotton-Rock).

When did SP actually drop schedules/train orders in favor of DTC? I'm thinking of the Modoc, the Siskiyous (ABS by itself is not authority), Lone Pine (aka Jawbone), Mina and most of the many branches. I think SP had already switched before the 1989 GCOR, but after they bought the Cotton Rock.