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Can someone tell me the outside diameter of a circle of 21" track?

I could also use some help with track design. I want a single lane with a turn a round on each end. It looks like Bachmannn doesn't yet make a wye so I guess I would need to use 2 turnouts. I have available space of 30' in length but its only 30" wide.

Thanks

joe

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I have a pair of tracks by K-Line, I think they are 21 inch radius. The is self re-setting or will allow you to use a switch motor with it as it has a small hole for a switch motor to mount to the throw bar. Email me at phillyreading@gmail if interested in the tracks.

The 21 inch curves are very close to 21 inches, 21.5 inch diameter circle as I just measured the tracks.

Lee Fritz

Last edited by phillyreading
John Knapp posted:

Lee:

    My point was that I do not believe D21 curves can be used with the Y Tracks. As far as I know, the Y Tracks can only be used with D16 curves. Joe said he needs to use D21 curves for his Western Hobbycraft trolley.

John Knapp

  

I have used both 21 & 16 inch curves with the track, so it is possible to use either curve size but you may need 2.5 inch curve to curve straights between the curves and the track for proper spacing.

Lee Fritz

Joe:

I think you may be over-engineering it.  I have the Williams E-Z streets turnouts and it should be possible to make a loop on each end of your layout which lines up correctly.  My turnouts are permanently installed on my layout but by laying loose sections of straights and D-21 curves above my track it appears that a loop can be made using the available lengths of straight track.  Each loop would be constructed as follows: 

Coming out of the straight branch you will need a total of 20” of straight track.  Then you will use 5 consecutive D-21 curved sections followed by a total of 17.5” of straight track to connect back to the curved branch of the turnout. 

Because the last piece of the 20” straight track length on the straight branch will adjoin a curved track, as previously posted you will need a 2.5” C-T-S connector track section at that location so that leaves 17.5” of regular straight track.  Using the fewest sections possible would require one 10” section, one 5” section and one 2.5” section of straight (all narrow grooves) in addition to the 2.5” C-T-S.   

But the 17.5” of straight track length on the curved branch requires a 2.5” C-T-S connector track at each end.  So that leaves 12.5” of regular straight track needed which would be one 10” and one 2.5” straight section in addition to the two 2.5” C-T-S sections.

And as previously posted the outside diameter of the loops would be 16.5”.

HTH,

Bill

Joe:

I'm not familiar with that track planning software but I think you may be over-engineering it.  I have the Williams E-Z streets turnouts and it HAS to be possible to make a loop on each end of your layout which lines up correctly.  My turnouts are permanently installed on my layout but by laying loose sections of straights and D-21 curves above my track it appears that a loop can be made using the commercially available lengths of straight track.  Each loop would be constructed as follows: 

Coming out of the straight branch you will need a total of 20” of straight track.  Then you will use 5 consecutive D-21 curved sections which brings you back to 45-degrees from horizontal to line up with the curved branch of the turnout.  Then you will need a total of 17.5” of straight track to connect back to the curved branch of the turnout. 

Because the last piece of the 20” straight track length on the straight branch will adjoin a curved track, as posted in another thread you will need a 2.5” Curved-To-Straight connector track section at that location.  That leaves 17.5” of regular straight track.  Using the fewest sections possible would require one 10” section, one 5” section and one 2.5” section of straight (all narrow grooves) in addition to the 2.5” C-T-S.   

But the 17.5” of straight track length on the curved branch requires a 2.5” C-T-S connector track at each end.  So that leaves 12.5” of regular straight track needed which would be one 10” and one 2.5” straight section in addition to the two 2.5” C-T-S sections.

And as previously posted the outside diameter of the loops would be 16.5”.

HTH,

Bill

dobermann posted:

Thanks Carl. Unless I did something wrong with the software I can't get the ends to line up with the turnout. I'll will say SCARM appears to be more intuitive than RR Track since I'm not much on reading directions.

joe

I prefer SCARM, but RRT has it strengths.

I don't know if the small joiner tracks are available, but I use 2.5" straight to curve and a 2.5" curve to curve to make this work. It's 24" wide. There's 1 joint that's a force fit. I am not sure if EZ-Streets will do that like track does.

Right-click on the SCARM file and select save target as. Then open it with SCARM and you can try some combos.

Dobermann_D21_Streets_Return_Loop

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Joe,

I have been using RR-Track V5.0 for my track planning software so this picture is based on that software.  I do not run trolleys but do run modified streets vehicles.  Closing the loop with D-21 curves and a Wye showed a slight difference of .2 inches which in my experience, the track will allow you to do that and still work.  In trying to configure a reverse loop off of a D-21 turnout, the problem is that the straight track produced by the previous and current manufacturers are only available in multiples of 2.5".  You could look for one of the old K-line adjustable straight (one time adjustment) or modify a 5" straight by cutting and splicing.

streets reverse loops

If you decide on the wye and you also want to enter and exit the same leg each time the trolley passes through, check out my post from several years ago describing how I created a spring return for a wye.

I also had another post with pictures of a cut and splice that I did on a Wye (same method would apply for a straight track).  Have not found that yet, but will add if I come across it later.  Found it - it is in this thread about 1/3 of the way down.

Larry

 

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  • streets reverse loops
Last edited by L.J.

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