I’m just curious. What was the pulling power of a 2-8-2 Mikado? In other words, to put it in practical terms: On average, how many loaded 40’ box cars would that have been equivilent to?
Many thanks in advance. [:)]
Tom
Well there are a host of variables here – mountain railroading versus flat plains? A huge PRR L1 or a small drivered logging engine? In his photo book “Trains in Transition” Lucius Beebe had photo captions of mikados pulling freights were he mentioned 100 car freights. However Beebe was never one to let hard facts get in the way of interesting writing so you cannot swear that he actually counted the cars. But clearly on more-or-less flat midwestern railroads a mike was good for 60+ car trains, and that was in the day of friction journals, not roller bearings as today. I imagine it took quite a while to pump up the air with a train that long in the days of steam.
Dave Nelson
Stage,
That depends on a LOT of variables: train length, train weight, terrain, size of the engine, factor of adhesion of the engine, time period, time of day, etc, etc.
On average, a Mike could start a train of 3000-5000 tons. 3000 toms works out to roughly 75 40 ton capacity cars, while 5000 tons is 100 50 ton capacity cars.
Reality would be much different. In the steam era, trainmasters would have to look at the train weight, the ruling grade of a specific line, and the TE of the engines he had available, before he would release a train to the mainline. These three factors could mean a train of 165 cars or eight cars.
If you’re talking about standard USRA Mikes, 50-75 cars is a good, safe guess. The NKP’s redesigned USRA light Mikes would regularly haul 79 car trains, but they were fitted with booster engines in the trailing trucks, which gave them the same train starting power as a Berkshire (after about 25 MPH, the Berks were more powerful)
Dave & Ray,
Thanks for your input! [:)] I do realize that a locomotives pulling power depended on variables like weight and terrain. Forgive me for not being as specific as I should have. (I wrote it late last night and neglected to include those variables in my inquiry.) Ray, thanks too for including the info on the NKP Light Mike. The Light Mike was what I had in mind when I asked the question.
With that said, given a terrain that is relatively flat and an average tonage of a string of 40’ boxcars behind a USRA NYC Light Mike, would you still stick with 50-75 cars estimate? How much of an increase in pulling power would a Heavy Mike have over a Light Mike - i.e. given the same constraints as the scenario before?
Many thanks again for your knowledge base…
Tom
The USRA heavy mikado (which wasn’t used by the NYC - too heavy for the infrastructure, I assume) had 10% more tractive effort than the light mike, which translates to 60 cars instead of 54. The real advantage of the heavy was its bigger, freer-steaming boiler, which could roll those cars faster and be less likely to run out of steam on grades.
A quick trick for estimating how many loaded 50-ton capacity cars a steam-era locomotive could START from a standing stop on level track was one car per 1,000# of tractive effort. How many cars it could take over a division was more dependent on steam generating capacity. It would be entirely possible for a given railroad to have 0-8-0’s, 2-8-0’s, 2-8-2’s and 4-8-4’s with approximately equal tractive effort. The switcher could start X cars, moving them just long enough to trim up a string on a single yard track. The consolidation could slog along at 15-20mph, grades and headwinds willing. The mike could go over the road at 40-50mph - adequate, but not earth-shattering. The northern, on an equal tonnage of manifest freight, could lay its ears back and put the ICC-mandated 69mph speed limit in serious jeopardy.
As for determining train tonnage, some roads used a single “best guesstimate” weight per car, others had two separate “guesstimated” weights for loads and empties, while others, which were operating close to both locomotive and track capacity, would use the actual empty car weights and manifest load weights, then add X percent finagle factor. One size did not fit all (and
Thanks, Chuck! [:)] Good stuff and plenty of info to glean from!
Tom
Few days ago I have read that on several parts of its system the FRISCO used to run 6000 to 7000 ton trains with one of its large 4100 or 4200 2-8-2s.
I am collecting only brass models, and my smallest curves up to date are 80 inches radius/160 diameter, so I removed all metal extra weights from all of my freight cars (or in case of kits didn’t install them), so I am running a manifest train of 140 cars with only one steamer without any problem. And I feel that the smallest possible radius to run trains without extra weights is much smaller than I am using, I guess about 50 inches.
Great name you’ve got there, VAPEUR CHAPELON.
Mate, these “large 4100 or 4200” Mikes have got to be something out of the ordinary. 6000 to 7000 ton trains are a respectable load for multiple diesel units. What sort of tractive effort are you talking about?
The following quoted tonnages are for a loco with 63,000 lb tractive effort.
"The through load for a ‘heavy’ Garratt from Enfield to Broadmeadow was 650 tons, or 1000 tons if assisted by a Standard Goods 2-8-0 or a 59 class 2-8-2. From Broadmeadow to Muswellbrook, 775 tons was the maximum load, and from there to Murrurundi 650 tons. On the return, 1150 could be taken right through from Murrurundi to Broadmeadow, reducing to 1000 tons on to Enfield and assisted up Cowan Bank. Through loads on the south were 900 tons from Enfield to Goulburn, 560 tons thence to Demondrille, and 825 tons from there on to Wagga Wagga. Loads of 560 tons could be taken to and from Bungendore on the Cooma branch and up to 1400 tons on the Narrandera run. On the west, loads varied from 600 tons up Tumulla Bank’s curvaceous 1 in 40s, west of Bathurst, to 1100 tons between Bathurst and George’s Plains. The through load from Lithgow to Orange was 900 tons, with assistance up Tumulla Bank. In the 1960s, the only permitted instance of double-headed Garratts was on W44 ore concentrate train from Broken Hill to Cockle Creek. This through load of 1020 tons was worked by 49 class diesels to Parkes, thence by a Garratt and a 36 to Molong, where the 36 gave way to a second Garratt for the difficult climb to Orange East Fork. From Orange to Lithgow, the assistant Garratt from Molong, running bunker-first, took the train on alone. Electric haulage was provided between Lithgow and
Actually, the NYCS received 195 USRA light Mikes and 30 heavies. The lights were scattered throughout the system, but the heavies stayed on the NYC’s steel road affiliates, the P&LE and PMCK&Y, hauling heavy cuts of foundry material around.
And the NYC had Mikes that were MUCH heavier and more powerful than the USRA heavy, like their H-10’s, which boasted a total starting TE (with booster) of 78,1490 pounds, or 18,390 pounds more than the USRA heavy.
The whole reason that the NYC didn’t have more USRA heavies wasn’t a matter of the infrastructure. As with all large roads, they just chose to design their own engines. The USRA Mikes were forced on them by the USRA, and they did put them to good use. But unlike some of their affiliate roads which liked the USRA design and kept it well after the war (like the NKP), the NYC thought that they could do better. And they did with their H-10 designs, which ultimately led Lima to the whole “superpower” concept (an H-10 was Lima’s testbed engine before they came up with the A-1)
But the heavy’s boiler wasn’t all that much larger. And if the greater steam output really did equal better overall performance, why wasn’t it copied more than the USRA light, which was arguably the most popular Mikado design in North America? With the same size cylinders and drivers between the light and heavy Mikes, their speed potential is the same, so that’s not the issue.
Well the Great Northern’s Class O-8 Mikados from 1946 had the following specs.
Starting TE. 77,300 lbs.
Driver Diameter 69"
Boiler Pressure 250psi.
Cylinders 28" x 32"
Grate Area 98.5 sq. ft.
Weight on Drivers 325,000 lbs.
Total Weight 425,500 lbs. not including tender
The Frisco T-74s from 1930 have the following specs.
Starting TE. 66,100 lbs.
Driver Diameter 63"
Boiler Pressure 210psi.
Cylinders 27" x 32"
Grate Area 80.3 sq. ft.
Weight on Drivers 274,700 lbs
Total Weight 375,800 lbs.
New York Central H-10b Mikado
Starting TE. 63,470 lbs.
Driver Diameter 63"
Boiler Pressure 200psi.
Cylinders 28" x 30"
Grate Area 66.8 sq. ft.
Weight on Drivers 246,000 lbs.
Total Weight 347,000 lbs.
For Comparison here is a NKP Berkshire
Starting TE. 64,135 lbs.
Driver Diameter 69"
Boiler Pressure 245psi.
Cylinders 25" x 34"
Weight on Drivers 266,000 lbs
Total Weight 444,800 lbs.
OK, I would give those about 1,000 to 1,500 tons as reasonable traffic loads on relatively flat runs. Still short of 6,000 to 7,000 tons in my books. The roads that ran these must have had traffic standards of what trains they would put behind a particular class of loco on a particular route.
G’day John, Yes they did, just as the the NSWGR had load tables for all loco classes and routes. But the tonnage figures quoted for the Frisco and GN 2-8-2s are quite realistic. Bear in mind that our Garratts were conceived as light branchline power - an AD60 has a starting TE of 62,000lbs, less than either of the US locos. And both Mikados had larger grates and heating surfaces than an AD60, hence greater boiler horsepower. And our 59s were dinky little things compared to these US engines. There are many factors to consider when explaining why there is such an apparent disparity between freight train tonnage in the US and NSW. For one thing, the two roads mentioned didn’t have endless mile after mile of sharply-curving 1in33 grades on their mainlines, like we do - a very important difference. In NSW the biggest limitations on train length and tonnage in the steam era apart from grades were the capacity of the wagon drawgear, and the length of the crossing/refuge loops. I don’t doubt that an AD60 could haul a significantly bigger train they they were ever allowed to. But the hook drawgear wouldn’t take it, and there’d be nowhere long enough that you could put the train away. Imagine how many S trucks you’d need to make up a 7,000 ton train! You compare the perfomance of the US engines to diesels in MU. In many respects modern US steam locos could outperform them. Do you know what the maximum tonnage for a N&W A or a C&O H-8 was? All the best, Mark.
G’day Mark,
Yeah, I was being too conservative comparing to NSW loads for the reasons that you pointed out. However, I still have trouble with up to 7,000 tons behind one Mikado.
It is a pretty big lump of an engine with 77,300 lbs TE. If we take Chuck’s rule of thumb from earlier in this thread, then one 50 ton car per 1,000 lb of TE gives 3,850 tons. I am not sure what he meant by a 50 ton car. Maybe it is 50 ton load, which would possibly be 70 ton gross, and then we would be approaching 6,000 ton (5,390).
Regarding the D59, I thought it was a USRA light Mikado. However, from what I read here I must have been wrong. Perhaps it was a BLH export special.
Here’s a quote from a site I found while poking about: “when dealing with general purpose freight service, the ability to handle trains of 3000 to 5000 tons at good track speeds was accomplished with Mikados.” Looks like I might have to believe the big GN mothers could drag 7,000 ton after all. It was acknowledged as the biggest of Mikados on the site I looked up
I know (unlike many roads) Great Northern was very disappointed by the USRA heavy mikes they rec’d. They felt they weren’t up to the standards of their then current O class mikado’s…and they hadn’t built the O-8 yet, think they were only up to O-3??.
Where the O-8s ran the toughest grade would be about 1 in 140 except for a 1 mile section where a helper would be taken. Normally always either up or down but never steep.
The O-3s were the USRA Heavy Mikados. The sole O-2 was an oddball acquire with a purchased line, but the large O-1 Class were similar to the USRA Heavy Mikados. The nine O-3 owned by the GN were secondhand, with the end of USRA control of the railroads in 1919 some railroads turned back their USRA locomotives, the GN acquired 4 from the SP&S and 5 from the EP&SW. The GN only acquired 3 more Mikados built new, the first 3 O-7s. All the others were rebuilt from early Articulated locomotives.
Beaulieu,
Mate, have a look at this one: http://www.steamlocomotive.com/mikado/
According to that site Great Northern had 10 mikes made by ALCO, 190 from Baldwin and 92 that they made in their own shops.
You might be writing about a specific period, and that is where I am getting the wrong slant. That site does not tell us when they entered service and when they were retired. However, it looks like GN had a few more “MacArthurs” than you indicate.[?]
A quick trick for estimating how many loaded 50-ton capacity cars a steam-era locomotive could START from a standing stop on level track was one car per 1,000# of tractive effort. How many cars it could take over a division was more dependent on steam generating capacity. It would be entirely possible for a given railroad to have 0-8-0’s, 2-8-0’s, 2-8-2’s and 4-8-4’s with approximately equal tractive effort. The switcher could start X cars, moving them just long enough to trim up a string on a single yard track. The consolidation could slog along at 15-20mph, grades and headwinds willing. The mike could go over the road at 40-50mph - adequate, but not earth-shattering. The northern, on an equal tonnage of manifest freight, could lay its ears back and put the ICC-mandated 69mph speed limit in serious jeopardy.
A large number of years ago, I read a book on railroad engineering. Unfortunately, the title escapes me and all I can remember was that it was published in 1931. According to the author, the starting resistance of a car with solid bearings is 6 lbs/ton on level tangent track. This resistance falls to 3 lbs/ton when motion starts and increases as speed increases (curves and grades are obviously a factor). Given the slack inherent in a train, it’s entirely possible that a stock USRA heavy Mike could start a 10,000 ton train. Since a steam locomotive can pull any train that it can start, the Mike could keep that train moving as long as there was nothing that increased the rolling resistance of the train (grades and/or curves) to the point where the locomotive could not overcome it.
Andre
bush9245 wrote: <“Regarding the D59, I thought it was a USRA light Mikado. However, from what I read here I must have been wrong. Perhaps it was a BLH export special.”> The 59s were a derivative of a wartime US Army Transportation Corps design. Examples of these engines could be found in Turkey, India and Portugal. A USRA Light 2-8-2 is about the size of a D57… Cheers, Mark.
Oops!! I should have remembered the USRA engines were O-3’s, I have one afterall (from BLI - as it happens the O-3’s pretty much all ended up in the area I model, Duluth/Superior and the Mesabi Iron Range). In fact I was just looking at some of my GN books Wednesday while I was home getting a new furnace installed. Got kinda cold before the new furnace got running, maybe my brain froze??[D)]
BTW with Precision Craft announcing an HO 4-8-4 S-2 for next year, it would be awfully nice to see someone come out with an O-8 !!