I was wondering on a typical train or layout (I am in HO) What is the average number of cars that a single loco should pull and still be prototype? how about 2 or 3 locos pulling together? I have heard of some people pulling 100 or more cars, how many locos would it take to realistically pull that train? Right now I am running only one loco since the other one died, it is an F7A, and will pull 18 or 20 cars but it seems long for a single loco. Thanks, Mike
I don’t know if you have DCC or not (most likely) If you don’t, it won’t help anything to put more than one loco on. On the other hand, you can kinda tell how many you need by how easy the loco is running. I would suggest
1 loco = up to about 25 cars
2 locos = up to about 65 cars
3 locos = up to about 100 cars
For looks I would exactly double that amount. That is just my personal preference.
I am running DC for now but when running 2 identical F7A’s it runs smother with less track voltage than with 1 loco. When running 2 locos I can run a good smothe consistant speed at around 5-5.5 volts and with 1 loco I have to throttle up to around 7 volts and does not run as smothe at slower speeds . When pulling 2 locos I can pull a 25 car train up a 2.5% grade very well, with 1 loco I can pull a 19 car train up the same grade but not as smothe and have to throttle up to the 7 volt range to get to the top. Thanks, Mike
In 1:1 it really depends on the total loaded weight of the cars, length, type of locos available, and grades the train needs to get over. 60 empties on flat terrain is far different than 60 loaded with 1 percent grades.
Not a lot different in MRR’ing. In N-scale, I run trains up a 2 percent grade. I generally need to double the pulling power that is normally needed to pull the same cars on an even grade.
This can be done on DC too, so long as the loco speeds match up. I test this out by running two (or three) locos a foot apart. If there is a large variation in speed, then they should not be run together. If they are close, I chose the faster one and put it on point.
Mike,
I’m sure many here will agree…it depends upon the length of your layout and mainline.
On a traditional 4x8 a pair of locomotives hauling 12 freight cars that average 50ft. scale length may “appear” reasonably realistic. However, on a rectangular layout that’s 20 feet in length with a 35 ft long mainline, we could get away with a double or triple header hauling a 30 car unit train!
For passenger trains on a 4x8 you could have a double header pair of E units hauling six or seven, full length Walthers streamlined passenger cars (85ft. scale length) or 11 Athearn “shorty” (72 scale length) passenger cars.
What are the dimensions of your layout?
The answer to your question depends on what you consider to be a typical train layout size. A 20 car train would look long on an HO scale 4 x 8 layout, but possibly realistic on an 8 x 16 layout.
Protypically, I counted 70 cars behind a PRR GG1. This locomotive was rated at 4625 Horsepower, compared to 1750 HP for your F-7. You wouild probably need either 4 F-7s, two GG1s, or two modern Six-axle diesels to handle 100 cars on a level track layout. If you have a layout with elevation changes in a continuous loop, there is a critical train length, beyond which adding more cars to the train, does not increase the locomotive requirements because part of the train is always on a down grade.
It depends on the layout you have what kind of hills you have and so forth. It also somewhat depends on what your opinion is you have got some idea and from here you can go on your personal opinion.
The program Rail-ops uses the Prototype weight to assign an engine based on real data for the that engine. To applythat to your questions:
Real loco will pull “X” pounds
Real car weighs “Y” pounds
Grade of 2% reduces the pulling power by 65%. (look at horseshow curve and the helpers).
My 2-8-4 Burkshire using the Rail-ops formula on a 1.8% grade assigns 6 Passenger cars. Freight duty assumimg an empty car it assigns the same loco (51) 40 ft boxcars EMPTY when they are loaded (simulated of course) that drops to (23). To pull the (51) loaded it goes to the Y6b OR a helper of an 0-8-0 at the grade.
I enjoyed looking up the information to input into the program. The 2-8-4 as a model train will handle 50 cars easy but looked Funny.
There are a few factors to consider here;
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Size of layout. One comon practice is to have at least 2 train lengths between each station.
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Era you are modeling. A small early steamer will look proper hauling short trains, 1 to 10 cars. Where more modern trains will be 70 and up to 100+/- a few.
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Grades, I personaly have 2.5% grades and one deisel is restricted to 7 cars and a double header is needed beyond that, up to 15 cars.
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Personal choice of course.What are you attempting to acomplish. Some of the best layouts restricted train length because then you would have to run more trains in a given fast clock day to move the freight.
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Length of passing sidings, if you cannot get around other trains then the whole layout will become frozen, so to speak.
Mike,That is a open ended question with many answers.
What is the size of your layout? The maximum grade?
My thoughts are:
12 cars-one unit.
25 cars-2 -6 axle units or 3-4 axle units
50 cars-3-6 axle units or 4 - 4 axle units
100 cars -4-6 axle units or 6-4 axle units.
Remember to break your train into “cuts” when yarding the train.
Antonio, My layout is in a horseshoe shape, the right is about 9’ x 5’ with a simple oval with a spur to the center section, the left is a 4’ x 8’ with an oval on the lower with a spur, and a sort of oval on the elevated part of a mountain thus I get my 2.5% grade on the center section that is about 10’ x 2.5’ connecting the right and left sides. I have a streight run up the incline which is about 15-16 foot long. Really kind of a simple layout. A 25 car train looks alright on the long streatch but much longer and I could almost take the caboose out with the loco on the reverse loops. Thanks, Mike
To some extent, it’s personal preference. Does it look right to you, or doesn’t it. We have to do some selective compression in this hobby, and the ratio of power to train length is one of those areas. That said, I think the one in my sig. is a little heavy on the power to length ratio[:)]
This is a question with a lot of variables!
First - locomotive. In steam, that could be anything from a “Little Joe” 0-4-0T (I actually own two that are smaller!) to an Erie Triplex 2-8-8-8-2T (closest is a 2-6-6-2T.) In American diesel, this could be anything from an SW-7 to an SD70MAC. On level, tangent track an 0-4-0 might pull 8 cars with free-rolling trucks while that triplex, if weighted for maximum tractive effort and fitted with traction tires, would probably pull 200.
Second - 2 (or 3) locomotives. Same loco, or different? If doubleheading over the entire division, the locos should be matched in speed and control characteristics but won’t necessarily be the same types. If one loco is strictly a helper that couples up at the foot of the grade and uncouples at the top, speed matching is non-critical. N&W class A 2-6-6-4’s were routinely pushed upgrade (with a train between) by Y-class 2-8-8-2s, then turned loose to run at speeds that would have literally destroyed the Mallets. (Height of absurdity - Triplex on the point, Little Joe cut in just forward of the caboose. Even higher peak - Little Joe on the point, Triplex as pusher!)
Third - cars. All cars are not created equal. Weight and rolling resistance varies all over the landscape, especially if the same railroad couples whatever happens to be going eastbound into a single train. Three loaded 5-unit well cars will have more rolling resistance than ten AAR box cars, even with equally free-rolling trucks.
Somebody said that adding a second DC locomotive will not increase the number of cars that can be pulled. That is only true if the single DC loco is chasing its tail around a train set loop, all but coupled to the rear of its train. If there is room for more cars, doubleheading will allow more cars to be pulled. Doubleheading will also cause more amperes to be pulled from the power supply - po
You’ll have to help me understand a little better what you mean about the DC Loco’s. Why, if you add more cars does it help the engine. What if I have 200 ft of track and 1 engine and cars all the way around to my engine again. If I took two cars off I would have to add another engine?
The era you are modeling makes quite a difference. For example, last week I saw a CNE train with 2 locomotives (unfortunately I can’t tell you what kind, I’m not that savvy yet). They were road switchers, though. Anyway, they had 14 cars, 9 50’ or 60’ boxcars, and 5 of the center truss flatcars (there’s probably a more technical term). Anyway, those are longer and heavy cars than my chosen era, the New Haven line in 1948. So mine could realistically pull more.
I also recently saw two Housatonic roadswitchers with 2 boxcars. So even short trains occur for various reasons.
Looking at pictures for my prototype, most passenger trains were MU’d with two DL-109’s, or an FA1/FB1 in an ABA or ABBA configuration. They typically had 10-12 (the longest reference I’ve seen is 17) cars. In '48 this could be a mix of heavyweight, american flyer-style lightweights, and stainless steel streamlined cars, plus possibly some head end cars.
Freight trains were longer (up to 100+), but there were also many that were much shorter. They also used a variety of MU’s - the ABBA FA/B1 as above, 2, 3 or even 4 RS-1s, RS-2s or RS-3s (although not in 1948 for the RS-3’s - NH hadn’t purchased them yet), etc. In almost every case I have found they are using MUs for diesels, partially because the early diesels didn’t have as much pulling power as a steam, and the later diesels were pulling longer or heavier trains. Another thing to keep in mind is that the ultimate limit in train length (I think) is the strength of the couplers. You can keep adding locomotives, but eventually the drag is too great on the couplers. To compensate for this some railroads use an inline locomotive (in the middle of the train), and of course this comes into play on steep grades which is one of the reasons the helper is often at the end of the train.
Another factor is that railroads often ran MUs so they wouldn’t have to turn the locomotives. Later on, when turntables were disappearing, this became more of a necessity so it’s not unco
It depends. I moved 140+ cars in the yard (15,000 tons) with 2 GP38s. Fairly flat, and didn’t move it very far. Had to reduce tonnage. To switch to yard we usually use 2 GP38s, for power and braking when kicking cars. If the yard was built right, it wouldn’t be so bad.[:(].
For our big train, we try to figure 1 hp per trailing ton. If underpowered, you don’t make track speed, with upsets the RRs we run over using trackage rights. We use SD40-2s and GP38s. SD40 has 3000 hp, GP38 2000 hp. Each has 500 hp/axle. Most loaded cars are 130 tons, empties 30 tons. So, 25 loaded grain hoppers would be 3250 tons, handled by 1 SD40-2. 50 loads would be 6500 tons, 2 SD40-2s or 3 GPs. Some days the trains leave the yard with almost 100 cars, mostly empty, behind 2 GPs. Coming back loaded, we need to assign more power.
As for models, it depends on how much the engine pulls, grades, and how free-rolling the cars are. I’ve run 90+ cars behind 2 Athearn SD40-2s (weighted to 20 oz.) or 3 Atlas GPs at the club. Has a pretty good grade wrapped around curves. Using club cars reduces the total – they don’t roll as good, causes stringlining and other problems. Makes me use salty Anglo-Saxon modifiers[:(!].