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RE: [z_scale] Re: Recommended track gradient

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  • Greg Elmassian
    I think if you read back a bit, you will find that the 060 drivers were the same diameter, there is more vertical slop in the center driver journal. There was
    Message 1 of 20 , Jan 1, 2004
      I think if you read back a bit, you will find that the 060 drivers were the
      same diameter, there is more vertical slop in the center driver journal.

      There was a discussion about shimming the center driver journal. If I
      remember correctly, the center driver lifted in reverse, and pressed down in
      forward (this may be backwards)... This makes sense since the drive to the
      gear on the driver is pushed in different directions for the different
      motion.

      I think this discussion centered on either loss of electrical contact from
      the lifted driver, or loss of traction.

      I guess someone out there could measure the drivers on an 060 marklin loco
      to confirm this.


      Greg

      P.s. thinking more, I seem to remember someone posted a movie clip that
      showed the center driver moving "up".


      -----Original Message-----
      From: MOFWCABOOSE@... [mailto:MOFWCABOOSE@...]
      Sent: Thursday, January 01, 2004 10:30 AM
      To: z_scale@yahoogroups.com
      Subject: Re: [z_scale] Re: Recommended track gradient


      I don't think the middle wheels "lift" on 0-6-0 or other steam locos so much

      as they are intentionally made a millimeter or two smaller in diameter so
      that
      they do not contact the track. This is so they can get around the 145mm
      curves without derailing.

      John C. La Rue, Jr.
    • zbendtrack@aol.com
      ... For the longest time there was a folder in the archives that had photos of a converted frame...that kept the intermediate drivers on the rails, in both
      Message 2 of 20 , Jan 1, 2004
        Greg:

        > Then it was either a discussion on traction, or related to adding
        > power pickup to the center driver, and the problems with the driver
        > lifting in a certain direction.

        For the longest time there was a folder in the archives that had photos of a
        converted frame...that kept the intermediate drivers on the rails, in both
        forward and reverse directions. I went through all the picture folders in the
        archives and apparently the author has removed his pictures.

        Perhaps that person could re-upload those photos? The modification was not a
        tough one to make, and was reversible if you didn't like it.

        And yes, all but the first and last drivers lift up off the rails when
        running in the forward direction. And only the first and last have power pickup.

        Bill K.
        Houston


        [Non-text portions of this message have been removed]
      • Ralph Scott
        I worked out that 7 sections of 8530 track layed in a circular configuration and one end raise just high enough to clear a 8911 catenary mast works out at a
        Message 3 of 20 , Jan 1, 2004
          I worked out that 7 sections of 8530 track layed in a circular configuration and one end raise just high enough to clear a 8911 catenary mast works out at a bit over 4.8% gradient (42mm in 850 mm). A class 111 with 3 silver fish coaches will struggle to get up this gradient. Change the 111 for a 120 and this is no problem at all. Substitute again with a 141 (CoCo trucks) and this no go as was the crocodile. Try this with 0-6-0 diesel shunter and it is also not a problem. I tried this with class 50 steam loco. It made it up the slope with 2 silver fish carriages.
          Ralph
          ----- Original Message -----
          From: Glen Chenier
          To: z_scale@yahoogroups.com
          Sent: Friday, January 02, 2004 5:24 AM
          Subject: [z_scale] Re: Recommended track gradient


          --- In z_scale@yahoogroups.com, "Ralph Scott" <ralph.scott@x> wrote:
          > Usually the more driving axles a Z loco has the poorer its pulling
          >ability due to the locos weight being distibuted over more wheeles.

          A very interesting observation...

          Does anyone know of any testing that has been done to determine the
          optimum number of driving wheels for a given weight?

          If not, this might be a good time to start something. If you are
          interested, measure the pull power (maximum number of cars, their
          total weight, track grade etc) and weight of your various locos along
          with number of wheels and post the results. Maybe we can get some
          good data to help answer Ralph's question.



          "Z" WARNING! HANDLE WITH CARE! Highly addictive in Small DoseZ!




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          [Non-text portions of this message have been removed]
        • Greg Elmassian
          I want everyone to know that I did not pay Bill to post this! Bill, thanks, I went back and searched and could not find the info, but usually, my memory is
          Message 4 of 20 , Jan 1, 2004
            I want everyone to know that I did not pay Bill to post this!

            Bill, thanks, I went back and searched and could not find the info, but
            usually, my memory is pretty good (not too many senior moments yet!)

            Bill do you remember if the discussion centered on getting traction by
            getting the drivers on the rails in forward motion, or was it also coupled
            to better electrical contact? (My memory says it was a traction issue, but I
            seem to remember something about crossing the frogs in a switch).

            Regards,

            Greg

            -----Original Message-----
            From: zbendtrack@... [mailto:zbendtrack@...]
            Sent: Thursday, January 01, 2004 5:59 PM
            To: z_scale@yahoogroups.com
            Subject: Re: [z_scale] Re: Recommended track gradient


            Greg:

            > Then it was either a discussion on traction, or related to adding
            > power pickup to the center driver, and the problems with the driver
            > lifting in a certain direction.

            For the longest time there was a folder in the archives that had photos of a

            converted frame...that kept the intermediate drivers on the rails, in both
            forward and reverse directions. I went through all the picture folders in
            the
            archives and apparently the author has removed his pictures.

            Perhaps that person could re-upload those photos? The modification was not a

            tough one to make, and was reversible if you didn't like it.

            And yes, all but the first and last drivers lift up off the rails when
            running in the forward direction. And only the first and last have power
            pickup.

            Bill K.
            Houston


            [Non-text portions of this message have been removed]


            "Z" WARNING! HANDLE WITH CARE! Highly addictive in Small DoseZ!


            Yahoo! Groups Links

            To visit your group on the web, go to:
            http://groups.yahoo.com/group/z_scale/

            To unsubscribe from this group, send an email to:
            z_scale-unsubscribe@yahoogroups.com

            Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
          • zbendtrack@aol.com
            ... The photo s showed tiny brass shims added to the bottom of the slots that the middle axles fit into. The slots are deeper than the diameter of the axles,
            Message 5 of 20 , Jan 1, 2004
              Greg:

              > Bill do you remember if the discussion centered on getting traction by
              > getting the drivers on the rails in forward motion, or was it also coupled
              > to better electrical contact? (My memory says it was a traction issue, but I
              > seem to remember something about crossing the frogs in a switch).
              >
              The photo's showed tiny brass shims added to the bottom of the slots that the
              middle axles fit into. The slots are deeper than the diameter of the axles,
              which allow the axles to ride up on the idler gears when in forward motion.
              Easy enough to add..no drilling or gluing.

              The purpose was to maintain wheel-to-rail contact for traction. About the
              same time, however, a different author related his success in adding beryllium
              copper power pickups to insides of these same center drivers. Still another
              author added text/photos on tender pickup (my favorite choice).

              I guess the size of the yahoo archives is limited, and even old messages fall
              off the end of the earth in time. Which is a shame, because many questions
              are as perennial as grass.

              Hope this helps,
              Bill K.
              Houston


              [Non-text portions of this message have been removed]
            • jmac_han
              Fellow modellers / modelers, The Z_Scale message archives are intact, nothing has dropped off, yet! You ll notice on the home page that the archives are still
              Message 6 of 20 , Jan 2, 2004
                Fellow modellers / modelers,

                The Z_Scale message archives are intact, nothing has dropped off,
                yet! You'll notice on the home page that the archives are still
                listed going back to June 1999. No doubt the discussion you speak
                of still exists. Don't forget to search the archives right back to
                the beginning. A first search only looks at the last chunk of 500
                messages or so. Ya gotta keep goin'...

                I don't recall a folder in the photo section on this topic, however,
                if there indeed had been one and it no longer exists then it may
                have been among some older material cleaned out to make room for new
                member photos. I'm not saying that this actually happened, just
                that I and my co-moderators are the only ones, other than the author
                of the folder, who have editing privileges concerning Z_Scale
                content areas.

                Happy Hunting...
                Jeffrey


                --- In z_scale@yahoogroups.com, "Greg Elmassian" <greg@e...> wrote:
                > Well, now the mystery is solved, and you have answered my question
                why I
                > could not be sure if it was traction or pickup...
                >
                > It is a shame about these things dropping off the forum... Maybe I
                should
                > figure out when they fall off, and be sure to archive them. I've
                got room on
                > my web site, and I think I'll start being more aggressive about
                adding them.
              • de Champeaux Dominique
                .. ... The La Mesa Model railroad club (which operates HO scale Tehachapi Pass in San Diego, CA) says, for its maximum grades of 2.2 %, 8 towed axles (ie two
                Message 7 of 20 , Jan 3, 2004
                  ..
                  >
                  > Does anyone know of any testing that has been done
                  > to determine the
                  > optimum number of driving wheels for a given weight?
                  >
                  The "La Mesa Model railroad club" (which operates HO
                  scale Tehachapi Pass in San Diego, CA) says, for its
                  maximum grades of 2.2 %, 8 towed axles (ie two cars)
                  per driving axle. That leads to 8 cars per BB engine,
                  and 12 cars per CC engine.
                  Cheers,
                  Dominique

                  _________________________________________________________________
                  Do You Yahoo!? -- Une adresse @... gratuite et en français !
                  Yahoo! Mail : http://fr.mail.yahoo.com
                • Scott A. Whitmire
                  ... The only determinants of pulling power are the total weight of the loco and the power output it can produce. The number of axles *might* have an effect on
                  Message 8 of 20 , Jan 3, 2004
                    At 1/1/2004 08:29 AM, you wrote:
                    >--- In z_scale@yahoogroups.com, "Ralph Scott" <ralph.scott@x> wrote:
                    > >... Usually the more driving axles a Z loco has the poorer its
                    > >pulling ability due to the locos weight being distibuted over more
                    > >wheeles. ...
                    >
                    >A very interesting observation...
                    >
                    >Does anyone know of any testing that has been done to determine the
                    >optimum number of driving wheels for a given weight?
                    >
                    >If not, this might be a good time to start something. If you are
                    >interested, measure the pull power (maximum number of cars, their
                    >total weight, track grade etc) and weight of your various locos along
                    >with number of wheels and post the results. Maybe we can get some
                    >data to add to Ralph's observation.
                    >

                    The only determinants of pulling power are the total weight of the loco
                    and the power output it can produce. The number of axles *might* have
                    an effect on the amount of friction (it increases it), but the difference isn't
                    enough to matter. I've seen the calculations for tractive effort, and they
                    include weight and horsepower, along with some fudge factors for
                    wetness and grade.


                    Scott Whitmire
                  • Glen Chenier
                    ... loco ... have ... difference isn t ... and they ... Makes sense, did some web searches on static friction and looks directly proportional to force. Less
                    Message 9 of 20 , Jan 3, 2004
                      --- In z_scale@yahoogroups.com, "Scott A. Whitmire" <whitmire@i...>
                      wrote:
                      > The only determinants of pulling power are the total weight of the
                      loco
                      > and the power output it can produce. The number of axles *might*
                      have
                      > an effect on the amount of friction (it increases it), but the
                      difference isn't
                      > enough to matter. I've seen the calculations for tractive effort,
                      and they
                      > include weight and horsepower, along with some fudge factors for
                      > wetness and grade.

                      Makes sense, did some web searches on static friction and looks
                      directly proportional to force. Less wheels, more weight on each.
                      It would be interesting to measure the weights of different
                      locomotives and come up with matching traction comparisons.

                      MTL F-7s are 3 ounces and can pull a lot of train or running alone
                      can climb 12% grades (experimental test results, not recommended on
                      actual layouts).
                    • Glen Chenier
                      ... Increased locomotive weight increases traction, but does this make it even harder for a locomotive to haul itself up a grade? The original question was
                      Message 10 of 20 , Jan 3, 2004
                        --- In z_scale@yahoogroups.com, "Glen Chenier" <chenierfam@c...>
                        wrote:
                        > It would be interesting to measure the weights of different
                        > locomotives and come up with matching traction comparisons.

                        Increased locomotive weight increases traction, but does this make it
                        even harder for a locomotive to haul itself up a grade? The original
                        question was 'recommended track gradient'.

                        If others would like to take part in a 'tractor pull' locomotive
                        grade climbing comparison, here is a way it could be done by various
                        testers on a standardized test track fixture.

                        Fasten a couple feet of track to a straight board and attach power
                        wires.

                        Dirt can improve traction and give false measurements. Clean the
                        rails and locomotive-under-test (LUT) wheels just b4 testing with a
                        no-residue solvent such as 91% isoproyl rubbing alcohol. Cleaners
                        such as Goo-Gone leave a film on the rails that reduces traction, so
                        avoid these. Let the solvent dry before beginning the test.

                        Prop up one end of the board on any suitable support. Books are
                        useful for this.

                        Run your various LUTs by themselves (no attached cars) up the sloping
                        track. Keep raising the propped-up end on more books to make the
                        grade steeper until the LUT wheels start to slip with trying to lift
                        it's own weight.

                        Measure the rise over run to calculate the grade percentage at JUST
                        BELOW the LUT wheel slippage point.

                        Post your results.
                      • Svein-Martin Holt
                        I have not read the whole discussion, but some time ago,(october 2002) I made my own test on my AZL E8 A+B unit, because I was not satisfied with the number of
                        Message 11 of 20 , Jan 4, 2004
                          I have not read the whole discussion, but some time ago,(october
                          2002) I made my own test on my AZL E8 A+B unit, because I was not
                          satisfied with the number of cars this nice locomotive could handle
                          before it start to spin. The test can be found on this page:

                          http://www.platelayer.com/mj/zanlegg/loadtestAZLE8.asp

                          This engines are heavy, but still they can not pull many cars up a
                          grade. On flat surface(or very low grade) it works very well.
                          This AZL E8 A+B cab take a maximum grade of 5.7% before it start to
                          spin a little, with only their own weight. Other numbers can be
                          found in the link(table).

                          My experience is that the small F7's from both Märklin and MT manage
                          more cars than this E8(Of course, the B-unit is a dummy, and the
                          weight is not much lower than for the heavy A-unit, so much
                          tractionpower goes to move the B-unit). The main reason for that I
                          think, is the number of axels on each boggie. The F7-boggie has 2
                          axels, but the E8 has 3 axels. It looks like the F7 in total has
                          more traction with the 2x2 axels, because they have bigger pressure
                          on the track, compared to the 3 axels boggies for the E8(I have also
                          noticed the same with multiaxles steamers). It may also be a problem
                          that with 3 axels is is more difficult to have all power transferred
                          to the tracks 100%, compared to 2, where you have 4 "corners", with
                          25% of the weight on each wheel, and its more easy to have maximum
                          traction moved to the tracks with that configuration.

                          I will therefor limit the grade on any of my layouts to the smallest
                          possible value, so I will be able to run long trains with my North
                          American equipment. Its not so fun to have only 5 cars behind the E8
                          A+B. Its much better to have all my 30+ coalhoppers in a long drag.
                          I may need to have some tungsten powder in the engine to increase
                          the traction power.

                          My maximum grade will be limited to 2.3%, normally less than that,
                          to have as few problems as possible.

                          In my newest dream(dream, because it is only on the drawing table
                          yet), a small layout featuring Tehachapi Loop, the loop is max 2.5%
                          (2.3% for the outher track), other parts is between 1% and 2%. There
                          may be need for a helper or two, but that will be the same as for
                          the prototype. For this layout the grade in the other direction is
                          less that up the loop, because of longer runs, so the heavy trains
                          will only go down the loop? That may bee a solution. :-)

                          Regards,
                          Svein-Martin Holt
                          www.platelayer.com

                          PS: Follow the building on my new z-scale layout on this link, if
                          you are interested:
                          http://www.platelayer.com/mj/zanlegg/z_layout_e.asp



                          --- In z_scale@yahoogroups.com, "Glen Chenier" <chenierfam@c...>
                          wrote:
                          > --- In z_scale@yahoogroups.com, "Glen Chenier" <chenierfam@c...>
                          > wrote:
                          > > It would be interesting to measure the weights of different
                          > > locomotives and come up with matching traction comparisons.
                          >
                          > Increased locomotive weight increases traction, but does this make
                          it
                          > even harder for a locomotive to haul itself up a grade? The
                          original
                          > question was 'recommended track gradient'.
                          >
                          > If others would like to take part in a 'tractor pull' locomotive
                          > grade climbing comparison, here is a way it could be done by
                          various
                          > testers on a standardized test track fixture.
                          >
                          > Fasten a couple feet of track to a straight board and attach power
                          > wires.
                          >
                          > Dirt can improve traction and give false measurements. Clean the
                          > rails and locomotive-under-test (LUT) wheels just b4 testing with
                          a
                          > no-residue solvent such as 91% isoproyl rubbing alcohol. Cleaners
                          > such as Goo-Gone leave a film on the rails that reduces traction,
                          so
                          > avoid these. Let the solvent dry before beginning the test.
                          >
                          > Prop up one end of the board on any suitable support. Books are
                          > useful for this.
                          >
                          > Run your various LUTs by themselves (no attached cars) up the
                          sloping
                          > track. Keep raising the propped-up end on more books to make the
                          > grade steeper until the LUT wheels start to slip with trying to
                          lift
                          > it's own weight.
                          >
                          > Measure the rise over run to calculate the grade percentage at
                          JUST
                          > BELOW the LUT wheel slippage point.
                          >
                          > Post your results.
                        • Glen Chenier
                          ... smallest ... E8 A+B. Its much better to have all my 30+ coalhoppers in a long drag. This is exactly the kind of information that would be useful to anyone
                          Message 12 of 20 , Jan 4, 2004
                            --- In z_scale@yahoogroups.com, "Svein-Martin Holt" <post@p...> wrote:
                            > ...I made my own test on my AZL E8 A+B unit, because I was not
                            > satisfied with the number of cars this nice locomotive could handle
                            > before it start to spin. The test can be found on this page:
                            > http://www.platelayer.com/mj/zanlegg/loadtestAZLE8.asp
                            > ...I will therefor limit the grade on any of my layouts to the
                            smallest
                            > possible value, so I will be able to run long trains with my North
                            > American equipment. Its not so fun to have only 5 cars behind the
                            E8 A+B. Its much better to have all my 30+ coalhoppers in a long
                            drag.

                            This is exactly the kind of information that would be useful to
                            anyone buying a new locomotive, or designing a new layout with grades
                            and being able to predict the operating limitations. While 30
                            hoppers are indeed a nice sight and one of the strengths of Z, many
                            do not have the room for even this and must settle for shorter trains
                            and steeper grades if used.

                            In addition to measuring the slip grade limit of various locomotives
                            on their own, the information provided on car-hauling capability on
                            various grades is very helpful too. It is harder to create a
                            standardized test for rolling stock due to the many different types
                            and combinations, but it will give a good guide to all, especially
                            newcomers to Z scale.
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