First developed by the Union Pacific, the northwestern railroads where quick to see the advantages of the Alco 4-6-6-4 "Challenger"s on mountain curves. Using U.P. information and working closely with Alco designers, the Northern Pacific received a total of 21 Class Z-6 Challengers beginning in 1936 and 1937. As usual, the SP&S ordered 6 Z-6s (oil-fired) of their own in 1937. Two of these were later leased to the Great Northern.

The NP/SP&S/GN Challengers were became work horses, hauling freight yet capable of pulling the "varnish" as well at 50+ mph These powerful locomotives lasted though the end of steam. As with later versions, all were scrapped by 1959.

We at the Division Point felt that these earlier Challengers would be a great follow-on to the Z-7s and Z-8s. As usual, Division Point and Boo-Rim will offer this LIMITED EDITION project in different numbers of both classes. The SP&S and GN versions will also be offered. Lighting is included and these will be DCC-ready. With a limited number of pieces to be produced, you are well advised to contact your dealer to reserve yours!