A drawing of Baltimore and Ohio's Yellowstone class 2-8-8-4 EM-1. With the announcement of Union Pacific possibly rebuilding a Big Boy, here is a little comparison between the two.
..................EM1.....................Big Boy Length........125'10"...............132'9" Drivers.........64"......................68" Weight........1,010,700........1,250,000 Boiler PSI.....235.....................300 Traction.....115,000 lbs.......135,375
So in essence, a Big Boy could out pull, out run, and get to speed faster than a EM1. Both where the biggest for the railroad they ran. But alas, the Big Boy falls short of being the most powerful. That title goes to N&W's Y6b, 166,000 of traction effort.
Thirty EM-1s where built for the Baltimore and Ohio while none where saved while 25 Big Boys where build for the Union Pacific while EIGHT where saved. Much in the way that 425 Pennsy K4s where build while only 2 saved. Or even worse, 275 New York Central 4-6-4 Hudsons where build and none saved.
It's a wonder any of them were saved . Just think how much trouble and expense it is for volunteers and donors to rescue them . I imagine most were scraped out either during the depression or for WWII . Feeding your family or protecting them from people bent on world domination beats out saving a cool train . How sad that there had to be a choice at all .
Actually, these where built during WWII to meet traffic demands. One, rumored to be the one that was suppose to be saved, wasnt scrapped until the early 1960s.