Truck tuning

ggnlars Apr 12, 2021

  1. ggnlars

    ggnlars TrainBoard Member

    57
    37
    11
    Spent some time looking at various options for freight car trucks & wheelsets. I am early into an organized examination. What has become clear is that things vary from soup to junk as far as trucks & wheelset compatibility. I suspect some of it stems from the eleven different axle lengths. Before I make any rash conclusions, I wondered what is done with these cars to “tune” the trucks. It is clear that the used cars that I recently acquired had not been tuned. In fact they hardly would roll in most cases. So far the MTL replacement trucks are head an shoulders above any of the others including Atlas. That surprised me. I wonder if there are generations of Atlas trucks? Have yet to see a Kato truck, but that may change soon. So what is the “best” practice to get your freight cars to roll easily?
     
  2. tonkphilip

    tonkphilip TrainBoard Member

    149
    86
    12
    Larry, For me the best free-running freight trucks are Microtrains and they usually come with the freight car. I have Atlas cars but they are not as free running. The best free running passenger trucks are Kato and again for me, they usually come with the passenger car. I use other freight and passenger cars but they are not as free running. I know that MicroMark has a truck-tuner for HO but I have never seen or needed one for N Scale. - Tonkphilip
     
  3. platypus

    platypus New Member

    1
    2
    11
    I have recently started putting some graphite lubricant in the cones of some sticky trucks. Seems to help a little.

    Spreading the truck frame gently apart a little can also help reduce friction.

    Also check for any molding flash. I had a couple of Roundhouse kits that had some flash on the trucks that was catching on the wheel.



    Sent from my SM-G973U using Tapatalk
     
    tonkphilip and Moose2013 like this.
  4. Donstaff

    Donstaff TrainBoard Member

    184
    21
    13
    Why can't someone somewhere come up with an N scale "truck-turner" or more precisely, journal dresser?
     
  5. wvgca

    wvgca TrainBoard Member

    351
    167
    17
    maybe 'cause there are so many different axle lengths ?? So how long should it be ??
     
  6. ggnlars

    ggnlars TrainBoard Member

    57
    37
    11
    The problem is the total variation in the axles is more than the thickness in the truck bearings. So just tuning the truck is not going to solve the problem.
    The issue for me is cars with trucks & wheels that came from the manufacturer will not roll down a 4% incline. There tuning the truck should do some good. Yes, one can buy MTL trucks & wheels, but there should be an process that will improve the parts on hand.
     
  7. Inkaneer

    Inkaneer TrainBoard Member

    3,885
    610
    64

    Why "...there should be an process that will improve the parts on hand." What one would like to see and what 'should be' does not always correlate. I would like to see FM H20-44's produced in N scale. The probability of a first generation diesel being produced today is almost nonexistent. Basically there is an insufficient market for such a model. How big is the market for an N scale tuner? There is such a tuner in HO scale but I am not aware of any HO modeler who owns one. Consistency is one of the axioms of modelling. That's why we have certain standards that we all adhere to. For decades the MT truck and wheelsets have been the defacto standard in N scale. When you start mixing different trucks with different wheelsets and different track, etc. you inevitably find that somethings do not work and play well together.
     
  8. bill pearce

    bill pearce TrainBoard Member

    619
    262
    18
    I have not commented on this, because I don't wish to state the obvious. But I must, many have mentioned the subject of axle length in passing but no one has stated what would seem to me to be tho obvious. Apparently all HO axles are the same length, you don't see bags of replacement wheels in different axle lengths in hobby stores. I don't know why there is no axle standard in N, but the whole subject of standards in anything is an old fashioned concept. The easy answer is, did the OP buy the wrong axle length replacement wheels? It does seem that the OP had the answer all along but chose to ignore it.
     
    tonkphilip likes this.
  9. ggnlars

    ggnlars TrainBoard Member

    57
    37
    11
    HO axles are not the same length, variation in axle length has crept in in recent years. The bigger variation is the shape of the axle end and the truck bearing. “Tuning” does not necessarily mean a specific tool (although I do have a couple of Ho tuners), but a process. Yes, when the axle is to short that it won’t hold in the truck, then a new part is required. Additionally, if the axle length causes a bind that precludes the wheels from rolling, the a new part is likely warranted. However, I am seeing a number of situations where the something less aggressive is warranted.
    I have been running various combinations on a 4% down grade. Knowing the car weight, the distance to the measuring plane at the end of the run & the speed at the the measuring plane is enough to determine the rolling friction of the car through the conservation of energy. In this testing the results are rolls but stops to a velocity of 350 SMPH (scale miles per hour). The question is the
    highest result the best that can be done? Can the RBS results be improved and how much? Because of these results a series of Atlas cars with stock trucks & wheel sets have been tested. Here the result varied from RBS to 200 SMPH.
    The why do we care has to do with the train performance. Rolling friction is something that should be minimized, and there are techniques to accomplish this. The end result will be better train control, more cars pulled, lower current draw(power required) and higher speed if you need it.
    I will be attempting to “tune” the trucks to answer some of the above questions. These results will be posted on my site.
    Thanks,
     
    Last edited: Apr 15, 2021
  10. Inkaneer

    Inkaneer TrainBoard Member

    3,885
    610
    64
    Much too complicated for me. I use a 2% grade with a level runout at the bottom. I get a Micro Trains car that is weighted to NMRA specs and let it roll down the incline. I then use tape to mark the location where the car stops. This becomes my standard for other cars. I always have at least two powered locomotives on a train as that is what I see in these parts. Never had a problem with a performance issue using two locomotives. Train length on the club layout is limited by siding/yard track capacity (club rule). I can usually run 2 SD35 locomotives with 32 Atlas 90 ton hoppers plus a cabin car with no problem.

    I also change all my rolling stock to MT trucks with couplers.
     
    tonkphilip likes this.
  11. Maletrain

    Maletrain TrainBoard Member

    734
    336
    18
    First, the "truck tuner" would be the same for any truck, because it is only a cone shaped cutter that has a 40 degree tip angle for any truck. The conical axle tip with a 30 degree angle rides on the upper surface of the truck pocket cone - it doesn't rub all the way around.

    But, I have not found the pockets in the trucks to be much of an issue. I can take an old Roundhouse car with plastic wheels that hardly rolls at all and make it roll like an MTL truck by replacing the Roundhouse plastic wheels with BLMA or Fox Valley or EMS metal wheels. Usually MTL plastic wheels will work about as well, too, if the axle lengths match the trucks.

    Looking at the differences in what works well and what does not, besides the obvious issue of using the right axle length, it is the smoothness of the axle end cone and the smoothness of the wheel surface that runs on the rails. If those two surfaces are really smooth and round, the trucks roll very well.

    Looking at some Atlas replacement plastic wheels compared to MTL replacement plastic wheels under a 10X loupe, it is easy to see that the wheel rolling surface of the Atlas wheels is less smooth, and the Atlas wheels do not roll quite as well. Looking at some of the old Roundhouse wheel sets, it seems that the axle end points are simply not exactly round, much less smooth. Some of the new metal wheels that are not turned from solid metal on a lathe don't roll so well, either. Those wheels appear to be sintered metal powder, and don't seem to be as smooth or as round as the ones made on a lathe. So, don't just assume that any "metal" wheels solve the problem.
     
    tonkphilip likes this.
  12. ggnlars

    ggnlars TrainBoard Member

    57
    37
    11
    Thanks maletrain for sharing your experience. Some of the metal wheels that I have tested seem like they are rolling on gravel. I was wondering if some oxidation was the cause. The faults that occur in the non machined versions do not scale, so they must be more noticeable the smaller the size. This may also be the reason that the least friction cases have been with plastic wheels. The faults in the plastic must be smaller. Good input, thanks.
     
    tonkphilip likes this.
  13. Inkaneer

    Inkaneer TrainBoard Member

    3,885
    610
    64
    If my memory serves me correctly didn't one manufacturer produce a car with plastic wheels that was too free rolling? I think it was Kato's 2 bay covered hopper that is still seen on Ebay. I never had any but supposedly the cars would roll at the slightest touch which made coupling on to them somewhat of a problem.
     
    tonkphilip likes this.
  14. Moose2013

    Moose2013 TrainBoard Member

    152
    339
    14
    tonkphilip likes this.
  15. Inkaneer

    Inkaneer TrainBoard Member

    3,885
    610
    64

    Far easier to do what the big boys do and just slap on more power. Besides, modern model truck frames are made with Delrin or some other slippery plastic which is why we don't lubricate the journals and I doubt if a reamer would produce a better result. If the car won't roll properly then maybe switching to a shorter axle length is all that is needed.
     
  16. dualgauge

    dualgauge TrainBoard Member

    349
    198
    18
    In HO Scale reamer makes them roll a lot easier. There can be little burrs in the truck journal the reamer takes burrs out and smooths them also.
     
    mtntrainman likes this.
  17. HemiAdda2d

    HemiAdda2d Staff Member TrainBoard Supporter

    19,847
    14,034
    243
    What this topic needs is a defacto chart of axle lengths required for a given truck manufacturer. Can anyone assist?
    MT, Con-cor, Kato, Atlas/Accumate, MDC, FVM, Trainworx, etc.
     
    BoxcabE50 likes this.
  18. BoxcabE50

    BoxcabE50 HOn30 & N Scales Staff Member TrainBoard Supporter

    63,028
    9,430
    652
    I agree. I have seen plenty of these topics where no information is given, just a brand name. Specifics, down to a part number for a given axle/wheelset manufacturer, to fit a certain truck frame would be nice. Just throwing out an axle length, without knowing what frame it properly fits, does not help much....
     
    mtntrainman likes this.
  19. Maletrain

    Maletrain TrainBoard Member

    734
    336
    18
    Let’s start this way. Fox Valley used to make the following axle lengths in N scale:
    0.526”
    0.540”
    0.553”
    0.563"
    0.568”
    0.672”
    0.678”

    Let’s put rolling stock brand names after each, as we find them, continuing this thread until we get a nice compendium. I’ll start in the next post.
     
    Last edited: Apr 21, 2021
    mtntrainman likes this.
  20. Maletrain

    Maletrain TrainBoard Member

    734
    336
    18
    Let’s put rolling stock brand names after each, as we find them, continuing this thread until we get a nice compendium.

    Axle lengths in N scale:

    0.526”
    0.540” Micro Trains
    0.553” Roundhouse
    0.563" Bachmann (shorty passenger)
    0.568” Atlas (short passenger)
    0.672”
    0.678”
     
    BoxcabE50 and mtntrainman like this.

Share This Page