Slow roller

Discussion in 'N / Z Scale Model Trains' started by Dave R., Jul 9, 2007.

  1. Dave R.

    Dave R. Member

    I'm brand new to the hobby and am sure relieved to find some help. The files have already answered many questions I didn't even know I had. For now my lay-out is the dinning room table but I am clearing room in my shop for a 3X18 ft. bench. My immediate question is about my new Bachmann N 2-6-6-2 Mallet, it runs about 1/3 the speed of my 4-4-0 and my 4-8-4. It's beautifully detailed and looks great running (slowly). Is there a problem with this loco or am I just expecting too much. Is it possible it's running at scale? (the 4-4-0 American runs like a slot car!)
    Dave R.
  2. Jim Krause

    Jim Krause Active Member

    How old are your 4-4-0 and 4-8-4? What brand are they? If they are the older toy train variety equipment, there was no attempt to make them run at anywhere near scale speed. Fast was good. Bachmanns Spectrum equipment is scale in a lot of respects that aren't obvious. My Shays just waddle along at a very slow speed at full throttle. Big gearing reduction.
    Then there is the possibility that, being new, the locos drive train is tight or it needs lubrication. There are usually lube instructions with the loco. Running time will loosen things up after a good lube job.
    Go to Bachmanns website. They have a service called "Ask Bach Man" or something similar. Ask about the designed speed and see what they can tell you.
  3. Dave R.

    Dave R. Member

    Thanks for the quick response, Jim. The "Prairie Flyer" and "Empire Builder" are both new Bachmann sets. I guess my 6 year old Grandson and I were spoiled by the "non-scale" speed of these first two locos. The 2-6-6-2 is a Spectrum and probably is scale speed (I can't imagine those little drive wheels and rods turning much faster). I'll "Ask Bach Man" just to be sure though. We are very careful to "brake-in" properly.
    Our next loco, an Atlas Shay, should be in the mail, thanks for the "just waddles" heads up, I kinda thought that would be the case.
    Dave R.
  4. Biased turkey

    Biased turkey Active Member

    Welcome to the N scale forum Dave R.
    It's the 1st time that I see someone complaining because his engine runs at a too slow speed :)
    I don't own any Bachmann engine, only Atlas , Life-like and Kato ones. My 1st complain is that all those models have unrealistic ( too high ) maximum speed at full throttle. My guess is that in order to have a very low minimum speed the diameter of the gear in the gear-train must increase and that's a bad thing in a N scale engine.
    I know that DCC ( digital controller ) equipped engines has an option for adjusting the maximum speed.
  5. Dave R.

    Dave R. Member

    My layout should be 18 ft. when finished. I figure with two 12" radius' at either end, I'll have 16' of strait track; using a stop-watch and a little math I should be able to calculate with some accuracy the scale speed of my loco's. I'll use larger radius' and a ten foot straightaway to estimate (less accurately) the speed of my trains. This may all seem excessive but I hope this will be an opportunity to teach my grandson Ben some applicable and fun math, then we can red-line our controllers to reflect scale speed.

    My Daddy was a Fireman and
    my Momma ere, the only daughter
    of an Engineer.
    My Sweetheart was a Brakeman,
    and it ain't no joke,
    Shame the way she keep a good man broke.
    I got the fright train blues
    ( B. Dylan )

    Dave R.
  6. Bones

    Bones Member

    I own three B-mann 2-6-6-2's. All of them run at prototypically 'slow' speeds. It may seem like a crawl after running the 4-4-0, but it's probably a more realistic scale speed. If your layout is built for speed, try rearranging it a bit. Some long sweeping turns, and mild climbs to watch the 2-6-6-2 plug away at will probably make you just as happy.

    Don't think the 4-4-0 is sub-par though. I have always had an extremelly low opinion of this loco due to past experience with the original design. (broken before it was ever made - design) BUT... I finally got my hands on a pair of the newer design. Bachmann really turned around and got this one right. They are an impressive runner and the details are close enough for me. I'd buy more if I had the budget for it.
  7. Dave R.

    Dave R. Member

    I'm thinking about doing a logging concern as a large part of my layout. I think your right, the Mallet would look great cruising through passes, mountain cuts and avalanche sheds. My Atlas Shay should be here this week, now I need a Mikado. I'm really disappointed there is no "N" Climax.
    What I'd really like to do is build a three tier layout. The bottom tier (3X18ft) would fast mid-Th century trains. Above that (2X18ft) I'd have my "turn of the century" to '30's logging layout and next up my "Old Timey" stuff, (1X18ft.). Big plans for little trains! I've got a lot of research to do.
    Does anyone make an N scale Climax or Heisler?
    Dave R.
  8. umtrr-author

    umtrr-author Member

    Welcome aboard!

    There is no mass produced Climax or Heisler-- at least, not yet-- but there are occassional custom made ones sold on eBay and elsewhere.
  9. Dave R.

    Dave R. Member

    Is there somewhere I can get some "GOOD" 3 view drawings? I'm a reformed RC aircraft scratch builder and would love to try my hand at building some trains.
    My first scratch build will be some beam-less logging cars for my Shay, I've also seen a picture of a nifty little logging caboose that sits on one truck.
    Of course, building a loco is a whole deferent game!
    Right now I'm rebuilding 1/3 of my workshop to be dustfree for my layout. I've got my Grandson helping tile a new floor; I had to promise him I'd let him run over some scale cows with the 4-4-0!
  10. Bones

    Bones Member

    The RC world and MRR world are quite a bit different when it comes to drawings. It's not as easy to get rolling stock and locomotive drawings as it is for planes. Free, that is...
    There ARE quite a few available, but you usually need to pay a small fee in some way. Most drawings that are available will be found in MRR magazines, and some in books. Very few will be available online. But... If you have anything specific in mind, let us know. I'm sure someone has it on file. :thumb:
    And most drawings will be based on photos, so you get a side view, and ...maybe... a front view. Getting a top-down, or rear view is like winning the lottery.

    But... like I said, let us know what you're interested in and we can help you get there. (or maybe provide the drawings)

    Who doesn't like to run over some cows once in a while? I have a few bears I like to use, as well. :mrgreen:
  11. Dave R.

    Dave R. Member

    Thanks so much for the information Fellows. It's such a relief to know I can get the advice I need to make this project fun and educational, rather than an expensive drudgery. But, as I just PMed "Trainnut", I might have my caboose before my locomotive and need to start thinking about oooh...TRACK maybe?
    Thanks again,
    Dave R.
    Sanford Fl.
  12. 60103

    60103 Pooh Bah

    Dave: there is an old rule of thumb that a loco's top speed in miles per hour should equal the driver diameter in inches.
    This gives an interesting bit of arithmetic: (DD is driver diameter)
    Top speed is DD mph which is DD x 5280 x 12 inches per hour or DD x 5280 x 12 / 60 inches per minute.
    Driver circumference is DD x pi
    Driver revolutions per minute: DD x 5280 x 12 /60/DD/pi = 5280x12/60pi or 104/pi or approx 33.
    This is 2 seconds per revolution.
    (Now this seems a bit slow to me. Have I goofed somewhere?) There were exceptions -- high speed locos might exceed this rate while heavy freight might not get there at all.

    Edit: calculations all wonky. see replies below.
  13. Bones

    Bones Member

    It's too late at night for me to validate anything else, but this formula...
    upon close inspection this seems to be a constant, and not a variable equation.

    Because everything here is being multiplied or divided, the entire equation can be arranged any way you choose.
    DD x 5280 x 12 /60/DD/pi
    Haven't spotted the superfluous factors? Let me rearrange it a bit...
    DD / DD x 5280 x 12 / 60 / pi

    Dividing a variable by itself always equals 1. Having the DD in that equation does no good. It's an extra factor which leaves only constant numbers, and therefore a constant solution.

    :eek: Ok, I just realised your intent. I guess I was too tired and it took too long to sink in. I see now you were simply trying to state that it essentially comes down to 2 seconds per revolution no matter what size the driver. It seems quite slow to me too. Even slower when you consider the locomotives in this particular case...
  14. Dave R.

    Dave R. Member

    2 seconds per revolution? One Mississippi, two Mississippi. Can't be, or I'm really confused. The Mallet has got to be turning half a dozen rev's per second! I don't think it can do a two second rev. Maybe in the morning I'll be a little sharper or I'll make my six year old grandson explain this to me. ;0)
    Thanks Guys, Good night.
  15. tillsbury

    tillsbury Member

    It's a new one on me, but you appear to be missing a decimal point. 5280 x 12 / 60 / pi is 336, not 33. 5 revolutions per second sounds a lot, though...

  16. tillsbury

    tillsbury Member

    On the other hand, Mallard, with its famous 126mph run, and largeish 80" drivers, was doing 5280 x 12 x 126 inches, divided by 80 x pi is 31513 revolutions per hour... 525 revolutions per minute, 8.7 per second. Your rule-of-thumb seems reasonable. 8 revs per second is hammering along, 5 revolutions per second would be a sensible maximum speed for an A4 loco at 80mph (for an 80" driver).

  17. Dave R.

    Dave R. Member

    I've been thinking about this all day. An "N" mile is 33 feet, an "N" day is one and a half hours. But I just can't squeeze those apples and oranges into MPH. I've been working with 100 inch's of track being crossed in 10 seconds, but I'm missing somthing simple.
  18. 60103

    60103 Pooh Bah

    Ok, I blew it on my dollar store calculator/ruler. I thought the 33 1/3 rpm was too slow; that's the same as a wind generator.
    There was an occasion in Britain when someone observed their 9F class 2-10-0 goods locos on passenger trains doing 90 mph. (Can't find the driver size at the moment, 56"? 60"?) and someone proposed an official limit of the driver size in inches. It was pointed out that this would limit the A4s and similar to 80 mph; the proposal died.
    Dave: your time problem can resolve itself if you realize that YOU are looking at the train with 1:1 scale eyes and a 1:1 scale brain; the driver revolutions will look right if you time them that way. However, an N-scale day is actually 9 minutes long (at 1:160).
    "Scale" time is used to make the 10 feet between towns on a model RR take up a reasonable period on the schedule, but it falls apart when you start switching cars.
  19. Triplex

    Triplex Active Member

    Time doesn't compress. An N scale day is one day long! "Scale time", as you point out, isn't an exact science. It's related to selective compression, not scale ratio.
  20. Dave R.

    Dave R. Member

    24 X 60 = 1440 / 160 = 9.0, NOT 90, I misplaced a decimal point. That changes everything. Imagine the manic activity we'd perceive if we could look down on ourselves from a 1/160 bird's eye view. Are we wandering into "relativity"?

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