Some steam locomotives of artistic completeness are sold in Solo`s Steam Engine Service.
Union Pacific 3900 Challenger Silver
It is the largest operating steam locomotive in the world. In Whyte notation, a 4-6-6-4 is a railroad steam locomotive that has four leading wheels followed by six coupled driving wheels, a second set of six driving wheels and four trailing wheels. steamlocomotive.com/challenger has a lot on the explanation about this Locomotive.
Road Number3931 belongs CSA-2 that builted 1937.
It is a splendid characteristic of SL that we can watch such locomotives. Solonia Stenvaag which was an author poured love into these locomotives well.