As posted… Anyone know?
I’m guessing, but if this is a code 100 Custom Line wye, I think they have it configured to work with an 18 inch radius.
I have an old Atlas Custom Line Layout booklet which shows all the track components. The diagram indicates that the wye has 10 degrees of curvature, and this is the same amount as shown for a 1/3 section of 18 inch radius. They also show a diagram of a transition from a single track into two parallel tracks. As the track curves off from the wye, they use a 1/3 section of 18 inch radius to curve it back straight. Generally the comes outa needs to be equal to the goes inta for this to happen.
If your question is more related to what type of equipment can run on the wye, the booklet has a note that states that the “Atlas wye switch has a number 3 frog, so it is very compact and space saving, but since both tracks are curved, the curve is no sharper than in a regular No. 6 and it can handle all types of equipment smoothly”.
But again, I’m just guessing. Being a doubting Thomas, I’d probably get a piece of 18 inch radius and lay it on the wye to see if if the curves matched up.
The Atlas Custom Line - both code 100 and 83 - wye has the same geometry as the curved path of an Atlas Custom Line #6. The wye eliminates the straight path and combines the curve paths of both a LH and RH #6. Because both paths are curved equally, the frog angle is twice the angle of the #6, hence the #3 designation.
As with all turnouts with numbered frogs, the rail through the frog area is straight. So the turnout does not have a substitution radius like the Snap Switch, which has a curve frog and no number. For an Atlas #6 or Wye turnout, the curved portion of the closure and stock rails have a radius of approximately 40". NMRA RP12.3 gives more information on turnouts with numbered frogs (http://www.nmra.org/standards/sandrp/rp12_3.html). Note that almost all commercial #4 turnouts do not follow the RP very closely, commercial #6s are generally pretty close except for extending straight track on all 3 ends of the turnout.
probably more than you wanted to know
Fred W
Many thanks for the replies. [:)]
I’m a prime example of the “when all else fails, try reading instructions” for having not given this more thought before I posted. I’ve built numerous layouts over the past 35 years, with my last one over 12 years ago which went to “layout heaven” when we moved into a condo 2 years ago. Now that I’ve started a trackwork plan for the new benchwork I completed last winter it’s become obvious how much I’ve forgotten about turnout dimensional parameters that once was old hat.
After I posted dug through my reference books again and was surprised to find a dog-eared copy of the Atlas trackwork book (noted in your posts) I didn’t know I still had, and which answered my question … sort of. I couldn’t remember if a (Atlas) wye turnout was configured to work with a no. 6 turnout - which the book showed it is and with various wye/no. 6 turnout configuration examples.
And now, back to the drawing board. I turn 70 this month and this new layout will probably be my last one. Thankfully I’ve acquired a small hobby shop of HO inventory over the years so the cost of this new layout won’t be an issue - especially given today’s prices! I am toying with one new major expense which is going with DCC to eliminate the need for track/block toggle switches plus gain the ease of no hassle reverse loop configurations which I’ve always avoided having to mess with. But, with numerous 20 year old Athearn and initial issue Atlas RS3’s to convert I’m not sure I want to take on the wiring conversions and costs per engine vs running as is with my stable of engines and trusty ol’ DC solid state tethered but unplugable speed control.
In any event, starting from scratch again has reignited my model RR interest which had admittedly waned after plus-30 years in the hobby by the time of our decision to move into t
Interestingly, I’m building a wye entrance to a helix, so trains can go “both ways” up and down to my new second level. I happen to have a code 83 custom line wye, and 1 each of left and right snap switches, CL #4 (4.5?), custom line #6, super track #6, and a pair of Walthers #5.
If I use the CL #4s, every thing lines up perfectly, and the space between the switches is exactly three sections of 24" radius snaptrack from the wye to each #4, and exactly 4 sections of 9" straight snap track between the #4s. Coincidence?
All rail joints are tight, with no excessive gaps (almost none, actually), and all track is straight/perpendicular where appropriate… Additionally, if I lay a section of 24# curve over a #4, the rails line up perfectly with the diverging route of the switch, and with both routes of the wye.
When I try with the CL #6s, none of the above occurs. The Walthers #5s are close, but the diverging route is straighter for a longer run, not to mention it introduces a different manufacturer.
I have read elsewhere, but have not verified, that there are #3 and #2.5 Atlas C83 wyes. This could come close to explaining my experiences.
I do find it intereresting that using the stated combination everything “just lines up”…or…snaps into place, if you will.
Looking at the Atlas website I see only one code 83 wye listed. If it is laid out the same as the code 100 wye, it has a number 3 frog as mentioned in the Atlas book I listed above.
Walthers has wyes with frogs of 2; 2-1/2; 3; and 4 listed for code 83 in their catalog.
The Atlas book shows several different wye configurations, none of which use a 24 inch radius piece. This doesn’t mean a 24 inch radius piece won’t work. They just didn’t make 24 inch radius pieces when the book was published. The most compact wye they show uses three wye turnouts. I guess you could call it an equalateral wye. This wye has a full 18 inch radius piece and a 1/3 18 inch radius piece of snap track to connect each leg. They also show what they are calling scissors wyes using two #4s in one case and two #6s in the other. In these configurations each leg that diverges from the regular switches swings out and goes over a crossing piece before swinging back and connecting to the wye switch.