Based on units in service during the 1970s with:
• NEW – Auxiliary water tanks
• NEW – Rooftop mounted air tanks & piping
• NEW – Single steam generator with plated over/removed second steam generator
• NEW – Round spark arrestors
• NEW – Dual lens headlight in upper housing
• NEW – Pilot mounted MU hose brackets
• Brass Nathan M5 air horn
• Brass firecracker-type radio antenna
• Wire grabs & etched metal platform on nose
• Freight-type pilot
• Flush numberboards
• Deskirted fuel tank
• Farr air grilles