The railroad began experiencing mechanical problems with No. 17 in the late 1960s, so they then began using 2-8-0 No. 38 for most of their excursion needs. Sometime in the 70s, the steam tourist operation folded, and the LA&L, unable to find a buyer for No. 17, sold the engine to a private individual, who later sold it for scrap. The loco was cut up at Lakeville in 1970. For more details, check Railfan & Railroad's index on their website. They mentioned the scrapping of No. 17 in a story on the LA&L which appeared in their January 1997 issue.
Interesting side note: LA&L No. 17 was equipped with a Pennsylvania Railroad tender which appeared to be from a class L1 Mikado, although similar tenders were sometimes used behind their M1 class Mountain types and I1 class Decapods. Fortunately, the LA&L swapped No. 17's PRR tender for No. 38's before it was sold, so at least the Pennsy tender was saved.
Account #1: This locomotive was once displayed in Columbus, GA. It was thought to have been scrapped around the time of the Southern RY takeover. If that was true the timing was quite unfortunate as this would have been just before the SR steam excursion program and their search for operable engines.
Account #2: Upon retirement 451 was stored at the CofG shops in Macon, GA. It was scrapped in 1959 after the CofG was unsuccessfully in finding a city or institution to accept it as a display piece. Had the locomotive survived another year or two, the newly organized Atlanta Chapter NRHS would have accepted her.
Reference: Northern Pacific Supersteam Era by Frey & Schrenk, pub. by Golden West Books, 1985. Library of Congress Catalog Card No. 85-13189, ISBN 0-97095-092-4 (v.1); pgs 139 & 205