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Author Topic: Turn Table  (Read 6724 times)
« Reply #15 on: March 21, 2010, 09:27:19 PM »

Of course Jim is right, his ability to give people severe headaches is proof, and besides, he told me he was right. Roll Eyes Roll Eyes Roll Eyes Roll Eyes Roll Eyes
Jim Banner

Enjoying electric model railroading since 1950.

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« Reply #16 on: March 21, 2010, 09:52:00 PM »

Let's look at the turn table angle another way.  How many evenly spaced tracks would there be in a complete circle?  When you count around, there are 16 places where tracks can leave the turn table.  But they are not evenly spaced.  There is a gap where the crank is.  At first I had problems trying to figure out how many "missing" tracks" that gap represented, one or two.  Then I realized that turn tables are always built with an even number of tracks.  So that meant two missing tracks, for a total of 18 tracks if they were placed all the way around and spaced evenly.  That would make the angle 360 / 18 = 20 degrees.

Twenty degrees is twice the angle used in many real world roundhouses.  The reason for the smaller angle in the real world is the much longer tracks from the pit to the roundhouse doors.  The roundhouse in Durango Co. is a good example and both the pit and the 17 stall roundhouse are clearly visible on Google Earth.  Unfortunately, it, like many roundhouses, no longer have their tracks or their tracks are not visible.  A smaller roundhouse complete with turntable and tracks exists at Heritage Park in Calgary Alberta at 50o 59' 09" N  114o 06' 34" W and is clearly visible on Google Earth.  A couple of quick measurements and a bit of trigonometry indicate an angle of 10o between tracks.

Nine tracks or ten tracks in 180 degrees does not make a whole lot of difference.  But I am having trouble with 18o (or 20o) becoming 15o.  Fifteen degrees may work well with your program but that would give 180/15 = 12 tracks in a half circle and I think we both agree that the number in the photograph is rather less than that.  What is it that makes it look wrong at 20o or at 18o?  Is there anything other than the tracks looking too far apart compared to the real world?  Maybe your program is doing better than you thought.  The tracks on this model really are too far apart compared to the real world.

Didn't you know I have shares in an aspirin company?  I'll have to send you a bottle to thank you for saying I was right.


Growing older is mandatory but growing up is optional.
« Reply #17 on: March 22, 2010, 12:56:16 AM »

       Send the low dose kind Grin Grin Grin Grin Grin See, you told me you were right. Yampa Bob would have told you the same thing. Cheesy Cheesy Cheesy Cheesy Cheesy

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« Reply #18 on: March 22, 2010, 08:15:03 AM »

somehow that make more sense to me but then math isn't one of my strong points. I guess I'll just have to wait to get the actual Bachmann kit to see how it actually fits on my layout. And of course then I can play with motorizing it

I do it all for the love of my son Cameron
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