They are both very nice sets. I think we need to know what you are planning on doing to make a better determination. For instance - the red set can be pretty easily modified into one of ALCO's RS series engines. The Gulf, Mobile, and Ohio had many RS-1s and had a red scheme making it an excellent conversion choice. The Yellow set on the other hand is a great starting point for a cowl-cab unit. Santa Fe had F45s in their Blue and Yellow scheme.
GMO RS-1 outside...Chicago?
ATSF F45 in the 'Yellow Bonnet' scheme
edit: spelling