- EMD E7 A-B-B Southern Pacific Daylight red/orange.
- Alco-GE DL-109 A-A New Haven hunter green
- Alco-GE FA2/FB2 A-B-B-A Erie-Lackawanna
- BLW DR6-6-20 Shark Nose Pennsylvania Tuscan red whisker-stripe A-B-A
- EMD E9 A-B-B Union Pacific
- EMD F7 A-B-B-A Denver & Rio Grande Western "Bumblebee"
- EMD GP7 Missouri Pacific original colors 3 units
- F-M H24-66 Train Master Southern Pacific red/grey 3 units
- Alco-GE RS3 Delaware & Hudson blue/grey 3 units
- Alco-GE PA1/PB1 A-B-A Santa Fe
Since they affect people emotionally, I avoid contributing to "favorites" lists , but what can I say, I am having a weak spell, so, some folks like Fords and others like Chevys, but here it goes. I am safely inside the Panhandle of Texas, too far away from everything, to be worried about any potential rock throwers who might want to punish me for excluding a favorite.
I took your use of the word "save" as meaning getting these engines when they were being retired and still in operating condition, and keeping them operable for excursion and other use, not for display. Of course this roster is hopelessly huge for that purpose, and, when these locomotives could be had at scrap prices, there was absolutely no interest in preserving operating first-generation diesels, as there was a sufficient supply of steam locomotives for excursions. But any of the locomotives on my list would certainly warm the hearts of railroad enthusiasts, and, somewhat, the public. for their colors if for nothing else. New York Central did not make the cut. The lightning stripe is dear to the hearts of fans in former NYC territory (and to me also), but, off line, they are somber. The Pennsy shark noses were only included because of the unusual appearance of the carbody and the Baldwin diesels, as Brunswick green or Tuscan red aren't knockouts either, except to fans who remember the PRR fondly.
With the knowledge of what has transpired in the 50 years since the late 1960s, I would prune the roster to two which would have great visual appeal, the ability to be maintained, and 6,000 horsepower, the practical minimum to be able to handle a mainline passenger train of heavyweight cars without help: The A-B-B SP E7's and the A-B-A Santa Fe PA1/PB1/PA1.