How many can it pull?

Discussion in 'HO Scale Model Trains' started by Gary S., Nov 17, 2005.

  1. Gary S.

    Gary S. Senior Member

    How many average cars could an average model locomotive be expected to pull on a flat grade?

    On a 3% grade?

    For example, how many 40ish foot tank cars (Athearn) could be pulled by, say, a Proto2K GP-30 on the given grades?
  2. MasonJar

    MasonJar It's not rocket surgery

    MR now includes little graphs on the pulling power of locos in their review section. They also compare the reviewed loco against the "average". I don't know if there is a specific calculation you can do to find out how increased grades and/or curves decrease pulling capacity, but generally acceptable grades and curves can cut your train length in half or more... E.g. if you can pull twenty cars on the flat straight, don't expect to get even 10 up a 2.5% (for example) grade going around an 18" radius curve (for example). Both of those features appear on many layouts!

  3. Gary S.

    Gary S. Senior Member

    I've seen the graphs but didn't pay much attention to them. Reason I ask is I am wondering how much length to devote to staging tracks for an around-the-room shelf type layout... 6 feet long? 8 feet long? 10 feet?
  4. MasonJar

    MasonJar It's not rocket surgery

    Your staging should be as long as the longest rain you want to run. In 10 feet, you get about 20 40' cars, less if you need room for engine, or less if you run things like intermodal or autoracks...

    I would say that probably 6 feet is minimum useful length for any sort of staging.

  5. shaygetz

    shaygetz Active Member

    My two unmodified P2K E8s pulled 32 cars, running the gamut from 8 loaded flatcars to two older Bachmann auto-racks, about half of which are weighted to NMRA specs, without slipping a driver up 1.75% grades. The helix alone is a 1.75% 100+ foot hike. I would have run more but I ran out of cars. The train was easily 12+ feet long. Next week I'll be shooting for 50-70 cars with the same two engines. At this point, I have no problem believing a well maintained, unmodified P2K 6 axle diesel model could do 30+ cars.
  6. yellowlynn

    yellowlynn Member


    I didn't have any grades at the time, but a single P2K E8 pulled 102 NMRA weighted cars on the level around 2 40" radius curves on a 90"X24' layout. There was 14" nose to tail so it was always on 2 curves. It didn't slip, but it was just barely starting to grunt a mite.

  7. SteamerFan

    SteamerFan Member

    My MDC 3 Truck shay was pulling 40 36' cars with no drop in speed on a flat surface (I ran out of room and cars to fully test it's full power).
  8. Russ Bellinis

    Russ Bellinis Active Member

    If you are in the design stage of a layout, I would suggest making up a train and seeing what looks right to you. The number of cars an average locomotive will pull is probably somewhat irrelevant. If you are running diesels, you can do like the prototype and put a second or third diesel mu'd with the first one to pull the load. I remember Tony Koester talking about his Alaghenny Midland some years ago in the "Trains Of Thought" column in MR. He mentioned that he originally designed the layout with passing sidings to fit a train with ten cars. He discovered when operating that 10 car trains didn't look realistic to him and he needed to run 20 car trains. In order to operate with 20 car trains, he had to go back and lengthen all of his passing sidings. What I'm saying is decide before you build how long you want your trains to be and how many locomotives you need to pull the load. Most trains out here in the West, even local peddler freights, run at least two locomotives. Once you decide how long you want your trains to be, you can figure out how long to make a passing siding.
  9. Gary S.

    Gary S. Senior Member

    Thanks for the great info and tests everyone! 30 to 40 cars! wow!

    I am in the design stages and didn't want to make the staging tracks longer than what an average loco could pull.

    Follow-up question to the veterans... how many cars "look right" in your opinion?
  10. Russ Bellinis

    Russ Bellinis Active Member

    The answer to that question depends on layout size, and how much you are modeling in that size. If you have a 4'x8' table with a small oval, it looks funny if the locomotive is chasing the cabboose. On a bigger layout if the locomotive is in one town while the caboose is still in the last town, it will look funny unless you have some sort of view block that keeps you from seeing both towns at the same time. At the other extreme from the 4x8 table, the La Mesa Model Railroad Club at the San Diege Model Railroad Museum has modeled Tehachapie in 1/3 scale in ho. That is they have 1 scale mile for every three miles on the prototype. They frequently run 100 car trains with midtrain or rear end helpers, and they look good. The bigger the layout, the longer trains you can run. As an aside, if you want to run helpers in midtrain or the back, you will need to run some dcc comand control. If you try to do it with dc and block divisions, you will have problems synchronising the locomotives.
  11. pgandw

    pgandw Active Member

    Iain Rice discussed this in one of his layout design articles. Here are his guidelines as I remember them:

    For a shelf layout, the longest train that looked reasonable was less than 33% of shelf length.

    You can't really tell how long a train is if its length safely exceeds your angle of vision; it just looks long. I believe this works out to a train length of about 10-13 ft, regardless of scale, at normal viewing distances. Most all viewers will consider the train to be "long" and have more cars than it actually does. In HO this worked out to at least 19 car trains (assuming 40ft cars) plus locomotive(s) and caboose. N would be about 35 cars to achieve the same overall length.

    Extrapolating from these 2, my guideline for tabletop ovals is that train length for good looks should be no longer than the length of the "straight" track between the turnback curves. Trains that extend into the curves at both ends of the oval simultaneously tend to look toylike, and appear disproportionately large compared to the "town" they are passing through on the side of the layout. Of course, passing track limitations also apply, and often cause shorter trains than the guidelines.

    These are guidelines, YMMV. Or, it's your railroad, do what you want to do.

    yours in counting cars

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