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Post by aceisback on Dec 14, 2013 2:42:40 GMT -5
I am just getting into Z scale, and purchased an AZL GP38-2 loco. I will be using Rokuhan track and I need to know what the minimum curve radius is for these locos. I have some 120mm radius curves, but the loco does not like them. I want to make sure I get the right track for these locos.
Thanks!
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Post by markm on Dec 14, 2013 8:32:43 GMT -5
By my calculations the GPs will just work with the 120mm track. I've seen success stories with 120mm and smaller, but I would suggest using 145mm track with the GPs, which for many years was the minimum Z radius.
Depending on your modeling goals, you may want to consider a larger minimum radius. Most of the steam engines and modern diesels want 220mm curves.
Hope this helps,
Mark
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Post by aceisback on Dec 14, 2013 17:48:44 GMT -5
Mine works with 120mm in forward direction, but if it goes a little too fast or if I run it in reverse, the wheels jump the track. By what I can tell with mine, the trucks don't turn far enough. I am going to be using 220mm anyway, so I shouldn't have any issues. Thanks for the info.
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Post by Rob Albritton on Dec 15, 2013 14:01:33 GMT -5
We design most of our locomotives for a minimum of 195mm radius curves. Now, I'm not sayin' that they will not do better than that! But, 195mm is the minimum Design Spec. Anything less and you are a test pilot (many test pilots are alive and well today, but a few of them didn't make it. It comes with the job.)
Also please remember that no two locomotives are built the same. John's GP38 might pull 120mm just fine, but Tom's GP38 might jump the rails at 130mm. Again, we warranty for 195mm. Anything better is bonus. Not saying it won't do it - just saying you may need more trial and error (and better track work) if you want to go tighter.
Note, our big hand made brass steam engines need wider radius curves. They will all work at 220mm minimum radius, but they run much better with wider curves (270mm is very helpful for them) This applies only to the GS3/4, Challenger, Cab Forward, and Big Boy. All other locomotives are good for at least 195mm.
I can also say that the RDC is good down to 145mm.
Hope that helps
-Rob(A)
AZL
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Post by aceisback on Dec 15, 2013 15:57:52 GMT -5
Thanks Rob. I was just curious because I have some 120mm curve sections that I was going to use if they would work, but I will be using 220mm anyway, so all is well. I will probably be getting a steam loco later on also, so I am making the layout compatible with everything.
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Post by markm on Dec 17, 2013 12:11:17 GMT -5
Also please remember that no two locomotives are built the same. John's GP38 might pull 120mm just fine, but Tom's GP38 might jump the rails at 130mm. Again, we warranty for 195mm. Anything better is bonus. Not saying it won't do it - just saying you may need more trial and error (and better track work) if you want to go tighter. AZL Rob(A), Thanks for the insight into the AZL design specs. By my calculations (which could be in error) a prototype GP38-2 would only be able to negotiate a 190mm curve if shrunk to Z scale. I do have to take exception to your example. A variance of 10mm in radius would imply a variation in truck spacing of 6mm or a truck swing variation of 5 degrees. That is way bigger than anything I've ever seen in my AZL GPs. As I recall from my measurements and calculations, the GP38-2 sits at 121.8mm +- 2mm. Your manufacturing process is much better controlled than your example would suggest. Mark |
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Post by modelwarships on Dec 27, 2013 22:54:10 GMT -5
I recently added a siding that narrows down to 170R using Rokuhan track. My GP38 was able to negotiate it just fine.
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