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Testing of SD'9's

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  • Matt Parker
    While I was testing the SD 75 I had on loan, I purchased two additional SD9 s and tested them. I wanted to find out how many of them I could hook together to
    Message 1 of 6 , Mar 30, 2009
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      While I was testing the SD 75 I had on loan, I purchased two additional SD9's and tested them. I wanted to find out how many of them I could hook together to achieve a greater pulling power.
      I started with 13 cars and on GP9. From a standing start, 1 GP moved the cars OK but would not climb a 2% grade. All it did was spin. I then added the second GP9 and it climbed the grade but slipped a bit here and there. When I added the third, the grade was climbed and continued up the grade about 14 feet total until I ran out of track.
      Having acquired 13 more cars, I began experiment with these engines adding 1 car at a time using 1, 2 and then 3 engines. I found that once I got to 17 cars, one GP would not move them. It sat there and spun. After adding the second it would climb the grade but just barely. 3 was no problem. I continued adding cars until I had all 26 cars behind 3 engines. From a standing start, without pulse control, the 3 GP9's managed very well to make it around the tight loop, climbing the 2% grade and proceeding up the entire length to the end without slipping or struggling. If I had had 4 more cars, I would have put them on as well. With the 3 hooked together, and sorting out which one moved the fastest, I'm convinced that on a flat surface they would have easily pulled 35 cars and perhaps even 40. Around the loop and up the grade though might have been an issue. I can elliminate the turn situation by expanding it to 12 or 16 inches which is what I intend on doing, but i may have to add a 4th engine to make it to the top of the grade with 30 cars.
      I have pictures of the various stages of my testing, which I will post in a few days.
      By the way, in arranging my freight cars, I put all the heavy ones up front of which there we 6 which didn't seem to present a problem most of the time.
      I also found that when I hooked the GP's together in triples, even though I had the slowest one in the rear, they did seem to push on one another from time to time. Odd how they do that. I would have thought that when these are manufactured, they would all have the same speed if they are made with the same parts with the same tolerances and so on. It took a lot of changing around to get them in the proper order as far as speed was concerned and I now have them numbered so if I use the three together again, I'll know which one goes first and so on.
      Does anyone else have this same problem and without using DCC is there an easy way to overcome this?
    • David Freehling
      your topic says SD9s, but you meant GP9s. if these are new, know that they need to be run in a bit to get them to function smoothly. secondly, run time also
      Message 2 of 6 , Mar 30, 2009
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        your topic says SD9s, but you meant GP9s.
        if these are new, know that they need to be run in a bit to get them to function smoothly. secondly, run time also takes a bit of the polish of the wheels and they will grip better. in general, though, you won't be adding that many more cars to your current assessment, just seeing some better (smoother) running performance out of the set.

        i put my fastest loco on the tail, so it has to pull the weight of the train first. this helps compensate its speed advantage.
        dave f.
      • Matthew Parker
        Yes I meant GP9 s Sorry. Putting the fastest in the rear eh? I was using it in the lead. In that case, would it not push the others? Two of these are new, one
        Message 3 of 6 , Mar 31, 2009
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          Yes I meant GP9's Sorry. Putting the fastest in the rear eh? I was using it in the lead. In that case, would it not push the others? Two of these are new, one 5 months old and one just 2 weeks old. The third one is used.

          Is there a way to rough up the tracks abit so that the wheels have something more to grip?



          To: z_scale@yahoogroups.com
          From: pinekirk@...
          Date: Mon, 30 Mar 2009 16:48:47 +0000
          Subject: [Z_Scale] Re: Testing of SD'9's





          your topic says SD9s, but you meant GP9s.
          if these are new, know that they need to be run in a bit to get them to function smoothly. secondly, run time also takes a bit of the polish of the wheels and they will grip better. in general, though, you won't be adding that many more cars to your current assessment, just seeing some better (smoother) running performance out of the set.

          i put my fastest loco on the tail, so it has to pull the weight of the train first. this helps compensate its speed advantage.
          dave f.









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        • David Freehling
          hello matthew, i wouldn t rough up the tracks, that will only cause bigger problems later (places for dirt to stick). putting the faster engine in the rear
          Message 4 of 6 , Mar 31, 2009
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            hello matthew,
            i wouldn't rough up the tracks, that will only cause bigger problems later (places for dirt to stick).

            putting the faster engine in the rear requires it to pull most of the train weight and thus the drag, then the lead engines actually help with the effort rather than drag a faster lead engine.

            my opinion.
            dave f.


            --- In z_scale@yahoogroups.com, Matthew Parker <echo31a@...> wrote:
            >
            >
            > Yes I meant GP9's Sorry. Putting the fastest in the rear eh? I was using it in the lead. In that case, would it not push the others? Two of these are new, one 5 months old and one just 2 weeks old. The third one is used.
            >
            > Is there a way to rough up the tracks abit so that the wheels have something more to grip?
          • Matthew Parker
            After reading your comments about this yesterday, I tried that, and I didn t really see much of a difference except that my fastest engine seemed to be pushing
            Message 5 of 6 , Apr 1 8:14 AM
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              After reading your comments about this yesterday, I tried that, and I didn't really see much of a difference except that my fastest engine seemed to be pushing the other two just from the way they started off from a standing start and continued around the track. I watched very closely the couplers and the fastest engine in the rear, made the other two compress on the couplers and remaind that way during on complete run. But I will keep trying. Perhaps it will sort itself out.



              To: z_scale@yahoogroups.com
              From: pinekirk@...
              Date: Tue, 31 Mar 2009 14:50:15 +0000
              Subject: [Z_Scale] Re: Testing of SD'9's





              hello matthew,
              i wouldn't rough up the tracks, that will only cause bigger problems later (places for dirt to stick).

              putting the faster engine in the rear requires it to pull most of the train weight and thus the drag, then the lead engines actually help with the effort rather than drag a faster lead engine.

              my opinion.
              dave f.

              --- In z_scale@yahoogroups.com, Matthew Parker <echo31a@...> wrote:
              >
              >
              > Yes I meant GP9's Sorry. Putting the fastest in the rear eh? I was using it in the lead. In that case, would it not push the others? Two of these are new, one 5 months old and one just 2 weeks old. The third one is used.
              >
              > Is there a way to rough up the tracks abit so that the wheels have something more to grip?









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            • Larry Card
              I double-head my steam and have always had the best luck putting the faster loco in front. This assumes that the speed differential between them is not too
              Message 6 of 6 , Apr 1 5:12 PM
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                I double-head my steam and have always had the best luck putting the faster loco in front. This assumes that the speed differential between them is not too awfully great. Putting the faster loco in the rear where it has to pull the train first before pushing the front loco sounds good in theory, but I've found that the light weight of the cars doesn't slow the faster loco down enough to make that much of a difference. Going downhill I've had the problem of the faster loco in the rear simply pushing the slower loco out of the way, usually catastrophically if there are curves involved.

                Of course, this is in N scale, so YMMV.

                V/R
                Larry P. Card

                Franklinton NC


                > After reading your comments about this yesterday, I tried that, and I didn't really see much of a difference except that my fastest engine seemed to be pushing the other two just from the way they started off from a standing start and continued around the track. I watched very closely the couplers and the fastest engine in the rear, made the other two compress on the couplers and remaind that way during on complete run. But I will keep trying. Perhaps it will sort itself out.


                > putting the faster engine in the rear requires it to pull most of the train weight and thus the drag, then the lead engines actually help with the effort rather than drag a faster lead engine.


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