I found these pics some time back. I thought it would be interesting to compare the Northerns side by side, both being Baldwin products.
Fred, I read somewhere that Frisco's Northerns were copies of the Burlington's. No idea if that's true or not. Gabriel G.
They're very similar, but I do see a few differences between the CBQ O-5's and the Frisco 4500's. The CBQ units have an angled cab like the SF units. While the steam dome is shaped similarly to that of the Frisco units, the placement is a bit further back. The CBQ units also have some sort of water heater up front as well, but it varies by build group. I'm a bit rusty on my steam terminology, so if I misidentified something, let me know. http://www.rrpicturearchives.net/locoList.aspx?id=CBQ&mid=846
Collias describes the development of the 4500s from the Q engines (and the development of the MoPac's 4-8-4s from DRGW engines). The War production board told the RRs to shop around for plans to reduce the load on engineering resources during WW II. It was much less resource-intensive to tweak existing designs than develop completely new ones.
