Reading in the Trains magazine of April 2004; in the article "Up the grade"...the Norfolk & Western way, by Ed King; on page 68 column 1, second paragraph, he elaborates on the simple formula: quote " A simple formula shows the severity of grades: Pounds of tractive force exerted to move a train up the grade equals 20 times the percent of grade, for every ton of weight. For example, if at 20 mph on level track a locomotive exerts 3 pounds to overcome the friction of the steel wheel rolling on the steel rail for a one ton load, on a 1% grade, it hast to exert 23 pounds of tractive force. Confront a steep grade, say 3% up Santa Fe's Raton Pass on the Colorado-New Mexico border, and it needs 63 pounds of tractive force, or almost 20 times as it needed on level ground. That's why mountain railroads have the bigger locomotive.
My question is this: Why didn't all the railroads crossing the Rockies use articulated steam locomotives such as the Challengers, true Mallets, Yellowstones, or Big Boys etc., as they all would have the greatest tractive effort?
In particular, why did CN and CP not order any of the articulateds for duty through the Canadian Rockies?
Probably many answers...some right, some wrong, some speculative...like my answers. First, complexity of the machine itself. Second curves weren't sharp enough to need to. Third, too heavy for the track and bridge structures so that size engine could not be used anyway. Fourth, not enough grades that such an engine would be needed. Fifth...they should have had a V8!
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CN and CP crossed the Rockies with very few major grades, and these were short enough that helpers were more economical than larger locomotives.
YOu are correct about CN, but CP eastbound has a lot of 2% and long enough that their Selkirks, 2-10-4's were design for passenger service and hauled their premier passenger trains in steam days. CP definitely could have used Challengers and the lack of art\culateds reflects conservatism more than anything else, in my opnion. Read the Classic Trains issue on 2-10-4's. Even the Selkirk's were conservatively designed and not the most modern when built. (Their 4-4-4 Jubelees were beautiful locomotives, but not up to the Milwaykee's Hiawatha Atlantics.)
It must have been a fairly straighforward calculus for the CP and CN. The population base, or what of it needed rail transport between the widely spaced coasts along the CP/CN lines back when the Selkirks were deemed necessary could not have been nearly as substantial as they were on comparative routes in the USA just across the border. With less population density, there would have been less of a requirement to move large numbers of people over the modest grades (compared to Raton, say). So, the trains were smaller. The Selkirks and Hudsons were capable for the work they had to do, and when they were not, another engine could be added for the hard parts.
-Crandell
CN pretty much followed water all the way through the mountains, and this is shown in that their SD40s were ordered without dynamic braking(!).
I had forgotten about the grades on Kicking Horse Pass, which were plenty steep, enough for runaway tracks before the spiral tunnels. I agree on the point about conservatism. The Selkirks were useful on pretty much everything, and in multiple if necessary. I have seen pictures of as many as 3 lashed up to move trains.
IIRC, the Jubilees mostly stayed in the East, their high-stepping drivers not suited to grades. The streamlined Selkirks weren't short in the looks department either!
But the point remains that the steepest grades were few and so far apart that it did not pay to purchase a locomotive for an entire run but rather just have pushers in the needed locations. Diesels are a different story but even they would be similarly handled with pushers rather than huge locomotives for the entire route.
Santa Fe relied on helpers over Raton Pass with grades up to 3% (though some of the helpers were articulated or ex-N&W mallets). SF's policy of through operation dictated that pattern more than the grades. By contrast SP changed engines (often to Cab-forwards) in Bakersfield for the run over Tehachapi into the diesel era.
rcdrye Santa Fe relied on helpers over Raton Pass with grades up to 3% (though some of the helpers were articulated or ex-N&W mallets). SF's policy of through operation dictated that pattern more than the grades. By contrast SP changed engines (often to Cab-forwards) in Bakersfield for the run over Tehachapi into the diesel era.
Actually you are saying the same thing for both roads, rcdrye, in that they used pushers in districts hundreds of miles from other grade districts so that they didn't need or want big, heavy power in those miles in between. Thus track, bridges, structure, could all be lighter as could the engines...big savings of money.
henry6Actually you are saying the same thing for both roads, rcdrye, in that they used pushers in districts hundreds of miles from other grade districts so that they didn't need or want big, heavy power in those miles in between. Thus track, bridges, structure, could all be lighter as could the engines...big savings of money
SP just turned the lighter power back north at Bakersfield and used heavier power (not helpers) over Tehachapi. On the coast route helpers were used from San Luis Obispo north over Cuesta for passenger trains, but freights and the mail train often drew cab-forwards for the whole run.
Right. Each road rationalized its power and its power usages.
IN steam days, labor was the huge percentage of operating costs that it is today, and double-heading or triple-heading and/or helpers was far more common and much reduced by the mu capabilities of diesels, as well as greater tractive effort for a given rated horsepower. CP had conservative motive-power pracitce, and made money until well after WWII without much real challange because it had the line through all the population center, with CN serving a lot of wilderness in comparison. But when import and export freight started to become the large fraction of revenue it is today, CN has become in a better position, because of its lower-grades, at least eastbound.
If you want a reailroad that was really conservative in steam practice, look at the Southern. Too heavy a freight for a USRA MIkado, add a second one.
While the Santa Fe experimented with building articulated's for a couple of years, they were the odd ducks of the roster, and they never built any more (although as mentioned the did get some ex-N&W mallets during WWII.) Some of the early experiments were "jointed boilers" which were an unsuccessful design.
http://www.trainorders.com/discussion/read.php?11,1845249
Instead they relied on over 350 "Santa Fe" type 2-10-2's and also a number of 2-10-4 "Texas" types, of which the "Selkirks" are the Canadian equivalent wheel arrangement. For a Santa Fe steam roster see:
http://atsf.railfan.net/atsfstea.html
But the Sante Fe 2-10=4's were more powerful than the Selkirks, even though designed and built some ten years earlier..
NorthWest ... The streamlined Selkirks weren't short in the looks department either!
... The streamlined Selkirks weren't short in the looks department either!
True dat. One appears HO size in my avatar, tiny tho' it be.
daveklepper But the Sante Fe 2-10=4's were more powerful than the Selkirks, even though designed and built some ten years earlier..
Much more powerful, Dave, and it must have been because they expected a single engine to have to do some heavy hauling, but also at speed. I believe they had some large diameter drivers, and their piston thrust in the 5010 series was the highest recorded in N. American steam for any two cylinder steam.
Selector,
That is some mighty impressive modeling!
The CP had great success taking a simple streamlining treatment that didn't create many maintenance hassles, and applying it to all passenger locomotives. It looked pretty, and didn't hamper performance.
The Santa Fe 2-10-4s were designed as power that could lug, and go fast. Equally at home on fruit blocks and drag freights, they were among the best in ten-coupled power. They also looked pretty good, too.
http://www.railpictures.net/viewphoto.php?id=386970&nseq=1
Both of the major Canadian railroads were true trans continentals and operated a very extensive network of lines from the Atlantic to the Pacific. Consequently they opted for large numbers of relatively modest sized locomotives, Mikes and Pacifics being especially numerous. The rationale was that their motive power should be adaptable to most of their routes system wide. Mallets were simply too limited in their route availability, especially on lightly built secondary mainlines. They did experiment with an articulated 2-6-6-2 which featured the cylinders arranged back to back and centered between the sets of drivers. Kind of an odd configuration that didn't warrant extensive duplication.
But the CN went to Mountains and Northerns in quantity, pioneered diesel power, and in general was less conservative than CP. But in general what you say is correct. And labor costs were somewhat less of a factor then, so double and triple heading was less onorous.
I would appreciate any link or article in the Trains family that talks about these unnamed 2-6-6-2 articulateds.
What a fascinating idea!
Who made them and why did they not catch on? I'm guessing complexity and perhaps shortcomings from the manufacturer taking shortcuts.
Thank You for the link. I have bookmarked it and love to get lost in the pictures.
Ahhh, CN Northerns:
Takes me back to my days as a member of the Upper Canada Railway Society, and Steam Photo excursions behind 6167, a retirement/passing of the torch doubleheader with 6218 and 6167, and the subsequent excursions on 6218.
6167 is on display in Guelph ON, and 6218 in St. Catherines ON. Sadly a letter campaign did not convince the Crown Corporation to spend the money to rebuild it, after its inspection revealed a much needed retrofit/rebuild of the boiler systems and a few other worn components.
For years their sister 6213 was in a place of respect, beside the Marine Museum (previously barracks for turn of the century military), at the CNE (Canadian National Exhibition) in Toronto. With over a million people on average visiting the CNE for its 2 week run at the end of August, many a young boy would see her behind the black square bar fence and ask their dad, "can we go see it?"
Sadly it was moved to a new location outside of the roundhouse just south of the CN Tower in Toronto.
Unceremoniously dumped outside the roundhouse on a feeder track to the turntable, the movers removed the main rod and did not replace it; part of the moving proceedure I assume; the reason? the driver bearings did not line up. Obviously, when the crane lifted the engine onto the special flatbed, the counterweights on some of the drivers spun the axles and the ignorant moving crew did not know to realign the bearing races to reposition the main rod
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Perhaps JimValle is referring to the six CPR 0-6-6-0's built between 1909 and 1911 for helper service between Field and Revelstoke. Due to high maintenance costs, without any advantages from articulation due to their small size, the locomotives were built into conventional Class R2 2-10-0's in 1917.
Isambard
Grizzly Northern history, Tales from the Grizzly and news on line at isambard5935.blogspot.com
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