Well they did in 1984 (sorry). Here is a look at a bunch of Union Pacific's DDA40X "Centennial" locomotives when the UP called them back into service in 1984. From the WB Video Productions show "Diesels on the Union Pacific, 2 Disc Set" https://rfd.video/DieselUP | Railfan Depot

33K views · 9.5K reactions | A Pair of DDA40X locomotives is on this eastbound seen west and east of Cheyenne, Wyoming. From the WB Video show "Diesels on the Union Pacific, 2 Disc Set" https://rfd.video/DieselUP | Railfan Depot | Facebook

Union Pacific’s legendary Big Boy #UP4014 is rumbling through the heartland and visiting Iowa this week. 🌽 The world’s largest steam locomotive rolls through the state with whistle-stops in: September 4: Carroll September 5: Belle Plaine September 6: Grand Mound and Sterling, Ill. 📅 Check out the full schedule at UPsteam.com. We look forward to seeing you - 25 feet back! #BigBoyHeartland #UnionPacific #BigBoy4014 | Union Pacific Railroad