Actually F-3s were generally a freight engine (that’s what the “F” stands for), but some were used on passenger trains. The KATO N scale WP F-3s were painted in the passenger scheme, but the units were used in freight service at times before and after their passenger period.
That’s one way. Although the Scenic Ridge layout in general is fairly limiting in terms of long-term fun, if you really want to stay with the track plan, I might try something like this to keep the passing siding.
An S curve between opposite 28" radius curves (#6 Unitrack turnouts) in N scale is not likely to cause any problems. That’s roughly the same as a transition from straight track to a 13.75" radius curve.
Andy
thanks Andy - I will get a better idea once I mock it up. I run a few passenger cars so it will be interesting. Bought kit on Amazon Dec 28 and it is taking forever. MB Klien was out of stock and it was cheaper than eBay prices by 30 BUCKS. Hardly worth the wait. $269 delivered. The track was $200.oo - Should get it this Saturday.
Except that’s not what he has. He has a 20-100 curve (9 3/4" radius) leading into an opposing #6 curve.
In addition, the tightest point through the KATO #6 is sharper than 28" radius.
I don’t see how an s-curve with one section at 9 3/4" radius is equivalent to a tangent leading into a single curve, but OK.
What he had previously could work. Or it might not, depending on the equipment, including his full-size passenger cars.
I’m surprised that there is disagreement about an alternative arrangement that could be more reliable, but that’s what makes horse races, I guess.
Best of luck.
I think I will try all the suggestions. I want it to run as seamless as my boring oval.[:D]
I cannot seem to get the turnouts correct with Rail Modeler using your diagram. I can get it very close but I have one small gap.[:'(]
While probably most railroads purchased F3’s for freight, on the Western Pacific the F3’s were purchased initally for passenger service. They were numbered in the 800 passenger series. They ran in ABBA and were WP’s first California Zephyr locomotives. The were latter split up. Late in their lives the remaing F3’s were renumbered into the 900 freight series.
The model in the picture is a steam boiler equipped F3A. Only half the WP F3A’s had boilers.
The first WP freight diesels were the earlier FT’s also inirially in ABBA sets numbered in the 900 series. Latter the WP bought F7’s (900 series) primairly for freight service. Latter they also purchased the longer, boiler equipped FP7’s (800 series) primairly for passenger service to supplement the F3 fleet and used mainly on the California Zephyr.
Hi Buffalo,
this is quite normal when using snap-track the moment you try out alternative track- arrangements. Kato is selling a flexible (lengthwise) piece to fill those gaps. My son faces the same problem with his Marklin layout.
As stated before especially long cars, coaches and larger engines will derail easily when “tiny” snap track gaps are closed with force. This is the reason lots of folks are using flextrack anyway.
Smile
Paul
Thanks Paul;
I purchased two expansion pieces so hopefully it will help. I guess there is a reason why Kato no longer sells the Scenic Ridge Track pack as a pack- if they ever did.
This plan is not necessarily an improvement from the previous one. It reduces flexibility (eliminates a runaround, passing siding) and adds a very expensive peice of track for minimal benefit.
One problem with Unitrack is common to all sectional track, it makes a very rigid trackplan that rarely "flows’ with the scenery. Most track plans look like train sets. Track centers seem to be much wider than with non-Unitrack sectional track making yards and sidings have a larger footprint.
Note that with significant grades through tight (9 3/4" curves), your full-length passenger cars may not run as reliably as you like through the Scenic Ridge layout. If absolute smoothness of operation is your goal, a different track plan with broader curves might be a better choice.
The good news on Unitrack is that you can tweak it. The challenge is that you are trying to match the pre-defined scenery of the Scenic Ridge, which was not designed for Unitrack.
As Paul noted, the KATO extension tracks are very useful for making up gaps in straight runs. Very small mismatches of a millimeter or two can sometimes be accommodated on the benchwork with a little shifting around of the track sections.
Like real life - Geometry & Physics are bumming me out [^o)]
No Reason as I explained before (I think) not to combine Unitrack with flex track as needed.
Good catch, I did not see that one! I saw the S curves between turnouts and the siding.
I now see four S curves in the original plan: two between 28" curves/turnouts, one between a 9.75" and a 28" curve, and another between a 19" and a 28" curve.
To approximate the severity of S curves (or of any transition between different and/or opposite radius curves), take the reciprocal of the difference of the reciprocals of the radii. This yields an equivalent transition severity between a straight (tangent) track and the resulting radius.
Using this formula between two opposite 28" curves: 1/(1/28 - (-1/28)) = 1/(2/28) = 28/2 = 14. (note the second radius is negated because it is opposite in direction)
Using this formula between a straight
Compared to four turnouts, the Unitrack double crossover is rather cheap! But you are right, it does remove a passing siding.
Track centers on Unitrack sidings are wider when #6 turnouts are used. If #4 turnouts are used, the track spacings are about the same as with Atlas and other sectional track.
Andy
The sharpest point of the curvature of a typical straight turnout is through the frog, not at the end. The tightest curves through the KATO N scale #6 are quite a bit sharper than the 28" you cite.
I don’t agree at all with the methodology of your complicated analysis, but that’s fine if you believe it reflects something practical.
Your analysis runs counter to some of the actual observed physics of model rail cars moving through s-curves. Offset forces through the couplers are often a major contributor to the problem, particularly for the longest cars and tightest curves, where the angles of the offset forces become sharp and friction through the tight curves is the highest. This is exacerbated by steep grades.
you guys have me really confused. I guess Saturday if I am able to mock up the track we will see what happens. Now I am scared nothing will work [U]
Cuyama,
I just pulled out a spare Unitrack #6 turnout and a matching 15 degree 28" curve section and compared them by sliding the rails against each other the length of the turnout, watching for any gaps between the rails as the slid past each other. The diverting route curvature matches exactly the 28" radius all the way through, including the frog (it is cast with the correct curvature).
There are certainly lots of factors that go into whether a curve transition will cause a problem, but experimentation has taught me that this analysis is pretty good, at least for the purposes of comparing to a reference curve/tangent transition, for a given pair of cars/locos.
In other words, if a car pair can make it through the equivalent curve/tangent transition, then it will make it through the equivalent S curve transition (assuming grade, weight/number of cars pulled/pushed, speed, etc. are the same).
In the same way we generally specify the desired/actual minimum radius of curvature on a layout (perhaps separately for mainline and sidings), we should also specify the desired/actual minimum equivalent curve transition.
This analysis does not predict a minimum radius of curvature, but rather the most severe transition between curvatures that a given pair of cars can negotiate reliably.
Let me explain the analysis.
The offset forces of which you speak are present when two coupled cars/locos are on sections of track with different radii and/or direction of curvature. The forces are proportional to the amount of offset between the two cars’ couplers. (Note: the angle of the forces is also related to the actual radius of curvature, regardless of the transition to/from any other radius. That component is not part of this analysis or discussion.)
When a car is on a curved track, the car’s coupler is offset from the center of the
Sorry aj1s, doesn’t compute linearly for me based on experience and I wouldn’t want you to waste any more of your time on me.
That’s a viable approach. The other would be to work on a new design that increases the likelihood of reliable operation based on best practices by eliminating as many s-curves as possible and broadening radii where you can, especially on grades. At the same time, you could work in more operating interest, if desired.
Either way, best of luck with your project, I’m sure you’ll work it out.