its my belief that an HO scale loco should be able to pull a reasonable amount of cars as to look prototypical, as union pacific would never have used a big boy to move less that 100 cars . that being said my bowser big boys have 12 ounces of pulling power which should exceed 120 cars easily each. are there any other ho scale locos with this kind of pull?
The PCM Y6b is a might puller. I haven’t attempted to max mine out, but on my 3.5% grades on the last layout, it had no hesitation taking twenty 70 ton hoppers with fake coal loads (BLI’s) plus a water tender and caboose. I’m not even sure it knew they were there.
I agree with you, a properly weighted and balanced HO scale locomotive with a decent gearbox and motor should be able to come close to what the prototype can do, albeit with what are actually empty cars.
I have resorted to the use of Bull Frog Snot on a few of my steamers. I am a fan of that stuff. It is easily applied after some practice and set-up, and relatively easy to get rid of altogether, or to clean off the worn layer so that you can cover the tire once again.
Crandell
Sure, lots of HO locos currently on the market pull very well.
My BLI/PCM N&W Class A (2-6-6-4) as easily pulled 85 average freights cars around a friends layout which has two helix grades of 1.8%.
His (or my) Rivarossi C&O H8 (2-6-6-6) did nearly as well at about 80 cars.
My Bachmann Spectrum USRA Heavy Mountains (4-8-2) have no trouble with 35-40 car consists - OR - 12-15 car passenger consists.
All my three or four unit MU’ed F units, from various brands (Genesis, Intermountain, Proto) easily handle 80 to 100 car consists.
A pair of Proto2000 E8’s will pull the paint off the walls, never been able to max them out.
My BLI/PCM Reading T-1 (4-8-4) will pull about 40 cars with no traction tire driver - with the traction tire driver - double that.
I have custom kit bashed heavy 2-8-2’s, made from Bachmann regular line 2-8-4’s, with some weight added, they pull nearly as well as the Bachmann Mountains.
I am a fan of pulling reasonably representive length trains and have designed my layout for trains in the 35-50 car range with grades under 2%. I have no problem getting reasonable performance from my motive power.
I do use a special free rolling truck setup which I developed after much testing. Most of my freight cars have Kadee sprung metal trucks that have been re-fitted with Intermountain metal wheel sets.
I don’t have anybodies BIg Boy, since I don’t model the UP, so I cannot comment on the pulling power of any of the current Big Boy m
I wasn’t aware that the Bowser Big Boy weighed that much, but relating pulling power to number-of-cars pulled is a sketchy way of expressing it. For example, I have a couple of baggage cars which won’t roll down a 2.5% grade without a push. [:-^]
A lot will depend not only on the rolling qualities of the cars, but also on their weight. Then add to that equation the possibility of curves and grades, and the number of cars pulled can vary significantly.
I’m pretty sure that, for test purposes, one would want straight, level track. The longest stretch of straight, level track on my layout is about 8’ in length, and a train which would fit on that would be unlikely to tax even an HO scale trackmobile. [(-D]
I’d have to do some hunting, but somewhere I have an article on determining the drag of a piece of rolling stock, and with that data and a formula for calculating compensation for grades on curves, one could probably come up with some useful data. Most HO scale locomotives (and perhaps those in other scales, too), when not fitted with traction tires, are limited to a maximum pulling power equal to about 25% of their weight. Unpowered axles and excess drag caused by things such as side rods and valve gear can decrease that figure, as can an imbalance of the weight distribution within the locomotive.
This modified Athearn BlueBox U-boat has a measured drawbar pull of 8.3oz…
Two of them easily handled a loaded 48 car coal train (I use live loads) up my curving 2.5% grade (compensated, it’s equivalent to just over 5%, as it’s on an “S” bend). They could have handled more, but I ran out of both hoppers and “coal”. [banghead] Total trailing weight was about 24lbs. The cars were mostly Athearn, Accurail, and Bowser hoppers, all with
While I agree with Wayne completely about the subjective nature of car counting to measure loco pull, I have yet to venture into the area of setting up any scientific equipment for my own testing.
My “car counts” are mostly based on using my fleet of 70 plus nearly identical 50’ Athearn Piggyback flat cars which are free rolling but weigh a little more than the average car - 4.3 oz each.
Regarding a more technical approach - Courtesy of another knowledgeable and talented modeler:
Model railroad track elevation and drawbar pull
Caveats
If you believe you are mathematically challenged… consider stop reading now.
Make notes… I will delete this post in a few days.
Following uses information based on testing by others and my own testing. Your results may vary depending on the controlling factors of your test environment.
1 inch of elevation to flat run of 100 inches of track = 1.0% (0.01) grade.
Rolling Resistance
Rolling resistance for real railroads is about 0.2%, for model railroads it is more like 2.0% i.e. a model railroad car will roll down a 2% grade on its own. This factor must be taken into consideration when calculating tonnage ratings.
Curve Resistance
Another factor is curve resistance, which is .04% per degree of curve for the real railroads and about the same for model RRs. The big difference is model RR curves are much sharper and this resistance is a very big factor. It is equivalent to around a 30%/R where R = curve radius in inches. An 18-inch radius curve will produce about 1.7% additional resistance. Most mountain model RRs are all curves, so compensating for them usually isn’t worth the time, but if you have to cheat on the ruling grade, do it on tangent track.
Locomotive Traction
An
Additional advanced reading on this and other model railroad subjects can be found here:
http://webspace.webring.com/people/ib/budb3/index.html
Sheldon
The only steam road power i run are a few older brass models. I did add a bit of weight and balance them to increase their pulling ability. I am not a fan of snotting the drivers, not that there is anything wrong with it, i just choose not to.
The backbone of my road power is a fleet of Atlas and Proto 1st gen geeps. Since they can be mu’d easily, my 35 to 50 car trains are never underpowered.
Yard engines are another issue altogether. Best pullers i have found to use in yard and transfer service are the Kato NW-2’s and RS-2’s. The early Atlas S-2’s with the Roco drive are really strong. Proto SW’s don’t quite match up to the Katos but they are decent, especially if mu’d. BLI’s are a complete let down for me.
I think yard power should at least be able to move a road train for purpose of switching.
When I worked on the Big Four at Brooklyn Illinois, we were next door to the GM&O yard. They were running 100 car coal trains our of southern iliinois to Commonwealth Edison near Chicago. These trains usually had 3 big 6 axle engines on them. Occasionally, they would need to throw out a bad order car somewhere near the middle of the train. This would require pulling and shoving back with about 50 or more cars totaling 7000 tons easily.
Since the road power had already cut off and gone to the house, they used a little early Alco S-1 or S-2 that was so old it had a wooden cab interior and the early Blunt trucks. That little engine would grab a hold of those coal cars and with a great cloud of black smoke pull them back at a slow walking speed. Clouds of dust would boil up around the engine from the sand being applied to the rails and at night, rings of fire appeared from the spinning wheels along with all the carbon residue erupting from the stack. That is why i can relate to the Atlas S-2’s and am happy they pull so well and run so smoothly.
There’s some interesting data HERE on the real ones.
Wayne
A Proto SD60 pulls great also.