Cab Forwards were designed to keep the crews from getting asfixiated from smoke while long tunnels. While a few other railroads considered purchasing the design, only the Southern Pacific Railroad ever bought any. Many wheel arrangements were used but most of them were of the 4-8-8-2 design.
Many Cab Forwards also contained a Seperate Air Horn. This Sound Profile also contains the ability to play this horn sound using Function 12. (remappable if desired)
AC-6 through AC-12 Cab Forwards Used a Saturated airpump mounted on the front of the boiler. These had a very distinct sound which we have gone through great lengths to duplicate.