ATLANTIC CENTRAL I don't have any BigBoy 4-8-8-4 locomotives lettered ATLANTIC CENTRAL. By design those locos would not have been successful in the eastern mountains/piedmont region I model.
I don't have any BigBoy 4-8-8-4 locomotives lettered ATLANTIC CENTRAL. By design those locos would not have been successful in the eastern mountains/piedmont region I model.
Sheldon, like many of your posts this was thought-provoking. I wonder how you come to the conclusion that a Big Boy would not have been successful in the Appalachians. Sure, the max incline in the Wasatch range was 1.14%, less than in the Appalachians, but I assume the Big Boys could have dealt with steeper inclines. Would the curve radii have been a problem? They are certainly pretty generous in the Wasatchs.
Thanks
DrW
DrW ATLANTIC CENTRAL I don't have any BigBoy 4-8-8-4 locomotives lettered ATLANTIC CENTRAL. By design those locos would not have been successful in the eastern mountains/piedmont region I model. Sheldon, like many of your posts this was thought-provoking. I wonder how you come to the conclusion that a Big Boy would not have been successful in the Appalachians. Sure, the max incline in the Wasatch range was 1.14%, less than in the Appalachians, but I assume the Big Boys could have dealt with steeper inclines. Would the curve radii have been a problem? They are certainly pretty generous in the Wasatchs. Thanks DrW
Mainline routes in the west, even in the Rockies, tend to have longer "straight aways" that allow higher speeds.
Curve radius and max grades are actually similar in the two mountain ranges, but straight aways simply don't exist in the east. And while the extreems are similar in both ranges, the Appalachian routes are continiously curvy and up and down, over and over again.
Driver size effects rigid wheelbase, rigid wheelbase effects speed on curves.
A Big Boy, with its 68" drivers, and four wheel trucks at each end, is considerably less "nimble" than even a B&O EM-1 with 64" drivers and a two wheel lead truck.
The EM-1 is without question the largest successful east coast articulated in terms of rigid wheelbase on each engine.
UP Big Boy - each engine wheelbase 18'-4", driver wheelbase 47-5", total wheelbase 72-5"
EM-1 - each engine 16'-9", driver wheelbase 44'-3", total wheelbase - 64' -1"
The more common east coast articulated locos like the N&W Y6b, even smaller wheelbases with only 57" drivers.
When east cost roads wanted higher HP modern simple articulated locos with larger drivers, you got six axle designs with higher axle loads like the N&W class A and the C&O H-8, having even shorter wheelbases of 13'-14' on each driver set.
So east coast roads needed locos better suited for sustained moderate speeds on winding routes rather than racetrack speeds across flat lands, that could make up for slow speeds around the fewer sharp curves of the west.
From Baltimore to the Ohio River the old B&O mainline was like a snake.....
A Big Boy would not have done well even on the C&O and B&O who had exceptionally heavy built trackage.
Notice fewer 5 coupled locos in the east as well.
Yes the B&O had their 2-10-2's, which ran mainly on the route thru Pittsburgh, which was straigher and had larger curves. They tried one on the old mainline - layed it over on its side........
Big Boys would not have done well in the east, and they all knew it.
Notice few pedistal tenders in the east as well, not as sharp curve friendly.....
The B&O never owned a 4-8-4, and if you survey 4-8-4's you find generally smaller drivers in the east for all these same reasons. There is a thread on the TRAINS Steam and Preservation forum about N&W 611 where I detail this.
So the ATLANTIC CENTRAL follows these engineering facts as well.....
We have 2-8-8-0's similar to the B&O, we have 2-6-6-4's built for us by the N&W, we have 2-6-6-2's like the C&O loved so much, and we have a few 2-8-8-4's like the B&O.
Our Northerns only have 70" drivers, and the only 2-10-2's are USRA lights with their small 57" drivers and relatively short 21' driver wheelbase for that wheel arrangement.
Yes, this is how much thought goes into freelance modeling, next I can tell you about our modern 2-8-2's......
Sheldon
To actually piggyback a little bit on what Sheldon said:
Santa Fe 2-10-4's with monster 74" drivers built to roll heavy trains at relatively high speeds.
The PRR (C&O copy) 2-10-4's had smaller drivers for eastern use. The PRR engines could start more train, but those (leased for two seasons) Santa Fe engines could roll that train much faster. However, the big drivers and high horsepower at relatively high speed were much better suited out west (except part of Arizona was actually too curvy and even better suited to 2-10-2's--the largest helper district in the US during steam).
Santa Fe actual dynamometer car tests revealed a horsepower curve well above 5000, which is rarely discussed because as denizens of the desert, they get overshadowed by other engines, but that is actually impressive for that wheel arrangement. S. Kip Farrington was there to record the test data in his book "The Santa Fe's Big Three".
So this goes to support Sheldon's contention that the various railroads really did optimize their steam locomotive designs to the divisions they had to operate. They did a remarkable job. We look back with today's engineering design tools and marvel at what was done with paper and slide rules.
John
John, thank you for that nice additional info.
Sheldon and John,
Thanks for the detailed answers. I learned something new today.
JW