One of the most remarkable locomotives of  the steam era in North America many decades ago, had to be the Southern Pacific Railroad's A.C Class (Articulated Consolidation.) 4-8-8-2 Cab Forewards.

These heavy duty freight and passenger service articulated steam locomotives, were designed to keep steam locomotive smoke out of the engineers cab, while passing through many long tunnels along the Southern Pacific Railroad mainline in California and Oregon.

Photographer Dick Kuelbs photographed this scene from Southern Pacific's steam to diesel transition era in 1956.

Locomotive # 4294, is the only preserved Southern Pacific Cab Foreward, and is on display at the California State Railroad Museum at Sacramento California.