Turnouts
Number 6 vs Number 8 Turnout
Quick answer
A number 6 turnout diverges at 9.53 degrees and suits most home layout mainlines; a number 8 diverges at a gentler 7.15 degrees and is reserved for high speed diverging routes and prototype-style junctions. Atlas HO Code 83 Number 6 Left-Hand Super Switch represents number 6; Atlas Code 100 Nickel Silver Mark 4 Number 8 Turnout Left Hand HO Scale represents number 8.
Atlas HO Code 83 Number 6 Left-Hand Super Switch
$27.409.53 degree frog angle, the practical default for most home layout mainlines.
Best for: main line and passing siding work in HO
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Atlas Code 100 Nickel Silver Mark 4 Number 8 Turnout Left Hand HO Scale
$30.727.15 degree frog angle, reserved for high speed diverging routes and prototype-style junctions.
Best for: main line crossovers where long cars diverge
Check price on AmazonThe verdict: number 6 is the practical default for most home layout mainlines, wide enough to run nearly anything smoothly without eating excessive benchwork length, while number 8 exists for the specific case where a diverging move needs to look and run like a genuine high speed prototype junction. Very few home layouts actually need number 8 turnouts throughout; most use them sparingly, at a single showcase junction or a critical mainline crossover.
The math behind both follows the same formula, frog angle equals 2 times the arctangent of 1 divided by 2 times the turnout number. A number 6 works out to 9.53 degrees. A number 8 works out to 7.15 degrees, a meaningfully gentler angle bought at the cost of a noticeably longer turnout.
On this page
- How much gentler is a number 8 turnout than a number 6?
- Do most home layouts actually need number 8 turnouts?
- Does a number 8 turnout take significantly more benchwork length?
- Is a number 8 turnout worth the cost difference over a number 6?
- Number 6 vs number 8 turnout, side by side
- Which one should you actually buy?
How much gentler is a number 8 turnout than a number 6?
By the frog angle formula, a number 6 diverges at 9.53 degrees and a number 8 diverges at 7.15 degrees, a real reduction in sharpness bought at real extra length. That gentler angle lets longer equipment cross the frog with less lateral kick and supports a higher realistic diverging speed, which is exactly why real railroads use higher numbered turnouts at genuine high speed junctions rather than everywhere on their network. Model the length tradeoff for your own benchwork with the turnout geometry calculator.
Do most home layouts actually need number 8 turnouts?
Generally no, and this is worth saying against the temptation to over-spec every turnout on a layout. A number 6, like Atlas HO Code 83 Number 6 Left-Hand Super Switch, already handles the overwhelming majority of home layout equipment and diverging moves smoothly. Number 8 turnouts like Atlas Code 100 Nickel Silver Mark 4 Number 8 Turnout Left Hand HO Scale earn their place at a specific showcase double crossover, a high speed passing siding, or a location a modeler specifically wants to model as a prototype-accurate high speed junction, not as a default replacement for number 6 everywhere.
Does a number 8 turnout take significantly more benchwork length?
Yes, meaningfully more. Because turnout number describes forward travel per unit of lateral divergence, an 8 versus a 6 is roughly a third longer for the same lateral offset, and that added length compounds fast across a full crossover built from two turnouts, or a yard ladder built from several in a row. A layout with limited benchwork depth should check actual published lengths before committing an entire yard throat to number 8 geometry.
Is a number 8 turnout worth the cost difference over a number 6?
Only where the gentler angle is actually doing work, such as a mainline junction carrying meaningful diverging traffic at a speed where a sharper number 6 angle would look or run wrong. For a yard, an industrial spur, or a mainline that mostly runs straight through with an occasional slow diverging move, the extra cost and length of a number 8 buys realism the layout is unlikely to showcase, and a number 6 remains the better value.
Number 6 vs number 8 turnout, side by side
A number 8 turnout diverges at a gentler 7.15 degrees than a number 6’s 9.53 degrees, but it costs meaningfully more benchwork length.
| Spec | Number 6 | Number 8 |
|---|---|---|
| Frog angle | 9.53° | 7.15° |
| Forward travel per unit of divergence | 6 | 8 |
| Best for | General mainline default | High speed junctions, showcase crossovers |
| Relative length | Baseline | Roughly a third longer |
The number 8 example listed here is Code 100 rail; check rail code separately from turnout number when matching a turnout to your track.
Which one should you actually buy?
Default to Atlas HO Code 83 Number 6 Left-Hand Super Switch for the general mainline and crossovers on a typical home layout, since it balances smooth operation against reasonable length. Reserve Atlas Code 100 Nickel Silver Mark 4 Number 8 Turnout Left Hand HO Scale class turnouts for the specific spot where you want a genuinely high speed, prototype-accurate diverging route, and confirm the rail code of any number 8 you buy matches the rest of your track before ordering, since number 8 turnouts are less commonly stocked in every rail code that number 6 is.
Frequently asked questions
What frog angle does a number 8 turnout have?
A number 8 turnout has a frog angle of 7.15 degrees, calculated as 2 times the arctangent of 1 divided by 2 times 8. That is a gentler divergence than a number 6’s 9.53 degrees, at the cost of a longer overall turnout.
Do I need number 8 turnouts for a realistic layout?
Not for the whole layout. Number 8 turnouts add realism specifically at high speed junctions and showcase crossovers, matching real railroad practice at those locations. Most of a home layout, including yards and slower mainline crossovers, runs perfectly well on number 6 turnouts.
How much longer is a number 8 turnout than a number 6?
Roughly a third longer for the same lateral offset, since turnout number describes forward travel per unit of divergence and 8 is a third greater than 6. Check the manufacturer’s exact published length for the specific turnout, since actual dimensions vary slightly by rail code and brand.
Can I mix number 6 and number 8 turnouts on the same layout?
Yes, and most layouts that use number 8 at all do exactly this, reserving the higher number for a specific high speed junction while using number 6 elsewhere for yards and general mainline crossovers. There is no compatibility issue mixing turnout numbers as long as the rail code matches.
Is a number 6 turnout good enough for a mainline double crossover?
For most home layouts, yes. A number 6 handles a mainline double crossover smoothly for typical home layout operating speeds and equipment. Only a layout specifically modeling a genuine high speed prototype junction generally needs the gentler angle a number 8 provides at that location.
Why are number 8 turnouts harder to find than number 6?
Number 6 covers the majority of home layout use cases, so manufacturers stock it in more rail codes and configurations. Number 8 serves a narrower, more specialized purpose, so fewer manufacturers carry it across every rail code, and a buyer may need to check availability before planning a layout around it.
Researched, not professional advice. This page is compiled from published manufacturer specifications, instruction manuals, published NMRA standards and recommended practices, and owner-review consensus, not hands-on testing. Figures described as a rule of thumb are hobby convention rather than a standard, and they are labelled that way wherever they appear. Always check a radius, a clearance or a grade against your own equipment before you cut wood or lay rail, because manufacturers vary and so does what your specific models will tolerate. Any permanent mains wiring in a layout room is work for a licensed electrician to your local code.