So many come to mind. Can't list them all. Here's a short (and incomplete) list I've personally experienced. South side of summit at MP 189 in Mission Viejo, CA, on Surf Line. Squiggles of old alignment visible. Well-known realignments on Cajon Pass on ex-ATSF North Track/Main 1 at Sullivan's Curve, Mormon Rocks, and on ex-ATSF South Track/Main 2 in and around Terrace Cut, and of course both mains at Summit. Martinez Spur on east side of Summit was remnant of old main. Ex-SP Soledad Canyon route, especially west of Lang, old cuts and tunnels abandoned. As noted earlier, UP's changes along Columbia not as extensive as SP&S, but check out Hat Rock State Park just west of Juniper, where old alignment really twisted through basalt formations. Change to ex-NP just east of Cunningham, WA, at time of BNSF doubletracking. Major changes to ex-GN on Trinidad Hill, extending apex of Trinidad Loop nearly a mile further up Lynch Coulee. Numerous line changes (not just abandonments) in and around Spokane for Expo '74 and BN merger consolidations. Ex-SP&S bridge and some roadbed still crossing I-90 and heading north toward tunnel under cemetery en route to Fort Wright Junction, with 1970s BN-built alignment coming off Latah Creek Bridge and overlapping part of SP&S before climbing up to Lyons to tie in with ex-GN. Plus ex-UP/MILW from same general location south into Marshall Canyon to Fish Lake, where active UP track begins. Some of the ex-UP/MILW is paved trail, some of it is dirt road. Ex-NP realignment at Spokane River Bridge east of Yardley. Ex-NP realignment between Rathdrum and Ramsey, ID, detours around steep rise that used to be tackled straight-on. Ex-NP change at Granite, ID, several times, parts of old grade north of current line used as local road (except for buried tunnel), and much older grade in ravine on south side of current line (east side of US95). Additional ex-NP changes along rest of Funnel toward Algoma. Numerous realignments across Marias Pass, elimination of tunnel west of Blacktail Curve, ease of curvature on east slope. Realignment and elimination of tunnel on upper Austin Loop on Mullan Pass. Multiple realignments on UP's Medbury Hill west of Hammett, ID, old grades still visible and noted on USGS topos. I could go on, and I haven't even touched the Northeast. As for new projects to come, there's been talk of BNSF adding a new line that skims across the coulees between Connell and Hatton, WA, much the way they plan to skim across the ridges of Abo Canyon.