Whats top speed on the 2900's? I thought I "read" somewhere over 100 MPH
Yes, markedly "over 100 MPH". Stories are legendary about them handling long heavy passenger trains, cruising at 100+ MPH. What with their running gear design and high boiler pressure (which also provides very high superheated steam temperatures), they would be easily capable of 125 MPH. I know that the UP FEF-3 class 4-8-4s were tested at speeds over 120 MPH, and although pretty similar to the Santa Fe 2900s, they were/are without roller bearing side rods.