N Scale Locos Pulling Power

Xrayvizhen Feb 8, 2021

  1. Xrayvizhen

    Xrayvizhen TrainBoard Member

    I have a question regarding the pulling power of N Scale Locos in general and one specific to a new Bachmann SD-45.

    Coming from the 3-rail O gauge world I'm used to engines with enormous pulling power even with ridiculously steep grades of 4% or more. One loco pulling 15 -20 cars up a 6" rise in 12 ft of track has never been a problem. On my door size N Scale layout I was careful to keep the grades to no more than 2% yet I find the SD-45 slipping in a climb while pulling just 7 cars; a mix of 4 box cars, a tank car, hopper and caboose. Six cars- no problem, but adding one more causes it to start slipping.

    So what's the deal? The Bachmann SD-45 doesn't have any traction tires. Is that the problem, or is there some other problem with that particular loco I need to troubleshoot? Or are ALL N-Scale locos just "weaker" than what I've been used to and I'll need to get another engine to help if I want to have a consist of 12 cars or so? Up until I added the 7th car the SD-45 was running very smoothly. With the sound turned off the motor is practically silent with the only noise being the sound of the wheels on the rails.

    Finally, if I get another loco should it be another SD-45 so that when I program it into the consist they'll have matching pulling power or can I look for another type?
  2. Doug Gosha

    Doug Gosha TrainBoard Member

    Not a lot of weight with most N scale locos and, without traction tires, not a lot of friction between wheels and rails. You just have to run a consist.

    Hardcoaler likes this.
  3. eposte12

    eposte12 TrainBoard Supporter

    look in to katos. not to bash your 45 is a very weak loco.
    Mo-Pac likes this.
  4. MK

    MK TrainBoard Member

    Certain locos just pull better than others based on weight, design, wheel metallurgy, whether broken in, sound or no sound, etc.

    A good way to check is read the analysis by Spookshow on a particular loco to give you an idea. Www.spookshow.net

    Also, what tracks are you using?
    Mo-Pac likes this.
  5. Xrayvizhen

    Xrayvizhen TrainBoard Member


    I bought the SD-45 on sale (cheap) but before I knew about Spookshow,.
    Mo-Pac likes this.
  6. John Moore

    John Moore TrainBoard Supporter

    It may be possible to increase the pulling power in two ways. One is to try and shoehorn in some Tungsten putty being careful of balance anywhere there is space for it. The second way would be a very light coat of Bullfrog Snot for just one axle and I do mean light. Bullfrog Snot can be thinned with water some.
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  7. Hytec

    Hytec TrainBoard Member

    Also check each of your cars for free wheeling. You may have a good engine, but your cars may be dragging.

    To check this, place a straight piece of Unitrak, assumed since you said Kato, on a flat level surface like a dining room table. Put a thin piece of material, possibly a tongue depressor, under one end. When placed on the high end, a good car should roll freely to the other end without being nudged.

    If your cars are dragging, I leave it to others how to correct it.
  8. nscalestation

    nscalestation TrainBoard Supporter

    Dirty wheels on the rolling stock can create drag. Closely inspect the wheels and clean if necessary. Also, metal wheels will generally roll more freely than plastic wheels. These are all things you can experiment with.
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  9. tehachapifan

    tehachapifan TrainBoard Member

    Another factor to consider is curve radii. A 2% grade with a tight radius creates a lot more drag than the same grade with a really wide radius. I have a ruling 2% grade on my layout with a 2.7% grade in a helix but my minimum curve radii on my mainline is 20". All this said, I rarely run a train with a single loco and instead run consists of 3 or more locos, where I can typically pull trains in the 30-40 car range.
  10. gcav17

    gcav17 TrainBoard Member

    Its always about weight distribution on the wheels. I primarily do steam. But. I have an old kato / con cor diesel. A DL 109. And it pulls for ever and a day. It's heavy as for as locos go and it's well balanced. Those are the keys to a good chooch.
    My brother (badland np) has a fancy new duplex. Very pretty. But not heavy enough and since it's that one company. Not reliable. Do your homework with spook. And don't be afraid to ask here. We are all full of tidbits and so far all these ideas are great.

    Sent from my SM-G975U using Tapatalk
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  11. NtheBasement

    NtheBasement TrainBoard Member

    If you want to compare N to O, consider the implications of the square cube law. https://en.wikipedia.org/wiki/Square–cube_law All other things being equally scaled, an O scale loco full of metal should have 3.333 (160/48) times the traction as N because that's the relationship between area (wheel/rail contact) and volume (weight).
    Mo-Pac, badlandnp and Onizukachan like this.
  12. Hardcoaler

    Hardcoaler TrainBoard Member

    Never knew that. Very interesting!
  13. tehachapifan

    tehachapifan TrainBoard Member

    I'm often amazed at the weight N scale locos can pull....at least when in a multi-unit lashup. If I try to move my longer intermodal train by hand when on a grade, it's incredibly heavy and quite difficult to move (with 1 or 2 fingers anyway). To think that, say, 4 relatively small and light N scale locos (typically Kato and Atlas) can pull it without difficulty is pretty amazing! It just doesn't seem like it would be possible at all.
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  14. Doug Gosha

    Doug Gosha TrainBoard Member

    I have never reached the limit an old plastic frame/metal weight Life-Like E7 or E8 can pull.

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  15. tehachapifan

    tehachapifan TrainBoard Member

    Ah, yes! Those would do well at a tractor pull!(y)
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  16. sidney

    sidney TrainBoard Member

    This bad boy Kato can pull like a mule it pulls this cleaning car plus 15 or 20 cars . its a monster. right now shes giving me problems of electrical nature.

    Attached Files:

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  17. mtntrainman

    mtntrainman TrainBoard Supporter

    You know you are putting down some torque with a LL locomotive when the worm gear pops the lid off the tower...lol. (y)(y)
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  18. porkypine52

    porkypine52 TrainBoard Member

    Check your grade, what you might think is 2% is really 3-4%. Add weight [tungsten & traction tires{Bull Frog Snot}] Know what each power unit's load limit is. If one is barely doing the job add another or two. I had a 25 car coal train, used to pull on our NTRAK layout, with double-headed Con-Cor 2-10-2's. Didn't want to put too much strain on a single engine. BREAKAWAY!! Looked down and see ONE engine pulling away from the other, the single 2-10-2 was pulling the 25 cars right along. Those engines can PULL!
    Mo-Pac and badlandnp like this.
  19. Massey

    Massey TrainBoard Member

    Pulling power varies from model to model and it varies greatly. I have an Intermountain SD40-2 and it struggles to pull my ONP Christmas train, and that’s made from 5 Kato Chicago Metra bi-levels. The P42 that came with the set pulls it just fine, no issues. The flip side to that I have an older Kato GP40 that is smaller than the SD40-2 and it pulls my Empire Builder just fine alone. The empire builder is almost 5’ long. So yea loco to loco makes a difference.

    oh and just adding a 1/4 oz tire weight to the roof of the SD40-2 made it pull the ONP train just fine.

    SD40-2 is DC only sound decoder friendly.
    P42 is DCC ready with a decoder.
    GP40 is DC only not decoder friendly.

    There are a few stats on the locos I reference.
    badlandnp likes this.
  20. NorsemanJack

    NorsemanJack TrainBoard Member

    Does anybody with a flat layout (no grades at all) have any problem with N scale locomotive pulling power? All my layouts have been flat with broad curves. I once defied the laws of N scale by pulling a 100 car train (all Micro-trains with lo pro wheels) with a pair of Atlas GP9s. I've also pulled a 30 car train with a single Kato Mike without the traction tire driver replacement (I have one, it's just never been installed). I get it that layouts with grades are "cool," but a loop or two without grades can certainly mitigate this "problem."
    Doug Gosha likes this.

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