Overstating The Case For A 2-8-0
The Crab Orchard & Egyptian Railroad was the last steam powered common carrier in the United States. In the latter steam era of the CO&E, the railroad’s power was a 1940 Canadian built 2-8-0 that had come south after spending her first career hauling bauxite on Quebec’s Roberval & Saguenay.
CO&E president Hugh Crane always said that #17 was the equivalent of a pair of GP38’s for the railroad’s purposes. That is probably true, as the railroad’s operations involved switching and moving short trains at a top speed of around twenty miles per hour over an eight mile railroad. Two geeps would have been overkill in that situation, and #17 was more than enough locomotive for the job.
That said, the nitpicker in me just has to take a look at the claim in a little more detail; was Crab Orchard & Egyptian #17 really worth a pair of GP38 diesels?
As much as I love you ol’ girl, I think not.
Any comparison has to start with an explanation of the difference between steam and diesel power; while they do the same work, they are essentially apples and oranges in how they go about doing the job.
The two measures in the amount of pulling power a locomotive can generate are tractive effort and horsepower. Tractive effort is simply the amount of pulling force the locomotive can exert, and horsepower is more a measure of how much work the locomotive can do. With steam locomotives, tractive effort is constant while horsepower varies. With diesels, the opposite is true.
A GP38 diesel is a two thousand horsepower machine, and two in tandem would result in four thousand combined horsepower. Tractive effort for a pair of ‘38’s starts at its maximum and drops as speed increases. A steam locomotive generates more horsepower as speed increases, until the boiler reaches its maximum output and the horsepower begins to drop. On modern high speed freight locomotives, horsepower peaked at around 40 miles-per-hour. Passenger locomotives peaked higher.
The first thing we have to take into consideration into a comparison between #17 and a pair of GP38’s is that #17 was not a high speed machine. She had 57 inch drivers, and the rule of thumb was that the maximum speed of a locomotive was the same as the driver diameter. With #17, 40 miles-per-hour would have been in the upper range of the locomotive’s operating speed.
Any 2-8-0 type locomotive, and #17 was no exception, was never designed with a high capacity boiler. The position of the firebox over the rear pair of drivers limited both the grate area and the furnace volume; both of which limited the steaming capacity of the boiler. Such a boiler was not capable of high sustained horsepower.
By the time #17 entered service on the CO&E, her capacity had been further limited. The locomotive was hand fired on the line, and the stoker she came with was never rebuilt and partially discarded. This was not an issue on the CO&E, where there was a lot of switching and slow running that hardly taxed a human fireman. In addition, both the locomotive’s feedwater heater and superheater were removed. These further limited the locomotive’s potential power, but again neither were an issue for the CO&E’s use of the locomotive.
The end result was that #17, while still a very capable machine for use on an eight mile short line, was a considerably less powerful locomotive than she had been on the Roberval & Saguenay.
On the other hand, a single GP38 diesel has enough power to pinch hit on an Amtrak train and keep four cars and a dead locomotive moving between 60 and 70 miles-per hour. A single unit would take a while to work up to that speed, but would be able to maintain it. Two units would accelerate a lot more quickly. #17 by contrast, would have never been able to approach such a feat.
When we think of a steam locomotive that would be able to produce four thousand horsepower, we are getting into the likes of the Nickel Plate Road’s famed Berkshires, which had a large firebox, a high capacity boiler, and the running gear to put that power to good use. Check out a video of restored 765 clipping off mile after mile at 60 miles-per-hour with a twenty-plus car excursion if you want an example of a high horsepower steam locomotive in action.
So with all apologies to Mr. Crane, while #17 may have been worth a pair of geeps to the CO&E, as much as I hate to say it I would have to give the prize to the pair of diesels.
Copyright 2010 – Mary Rae McPherson