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Author Topic: My First Derailing Question  (Read 1538 times)
Quentin

Working on a ceiling shelf layout


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« Reply #15 on: October 27, 2021, 10:03:54 AM »

hot glue it once it is in place, but only if you want it to be permanent. That's what I did on my last layout.

Quentin
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Quentin D.
crosswire

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« Reply #16 on: October 29, 2021, 07:35:19 AM »

Once I finish tweaking the layout, I may have to try the glue on the troublesome turnouts.
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Quentin

Working on a ceiling shelf layout


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« Reply #17 on: October 29, 2021, 09:15:04 AM »

It really helped me out. I still have one manual turnout that was from Bachmann's first-gen EZ-track manual turnouts. It's not a "springed" turnout; you have to switch it to whatever way the train is when in using the train, otherwise you get a derailment. I really just need to update everything to DCC.

Quentin
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Quentin D.
H5subway

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« Reply #18 on: November 14, 2021, 12:21:42 AM »

Those EZ track switches are REALLY sharply curved.  Almost like streetcar trackage.  They are bound to pick at wheels with the slightest molecular rail issue.  I got rid of mine and went to No. 5 and 6 switches.  The real railroads do the same thing, utilize as gently curvatured track as possible.
Well, unfortunately an HO scale version of a real railway curve would take up the entire room if not more (rough calculation, assuming a minimum railway curve radius of 175 m as per Wikipedia, which would be scaled down to 2 m in HO). Conversely, if those 18" curves were scaled up to life size (equating to a 40 m radius), would the real locomotives & freight cars be able to navigate them (let's assume they run at a slow speed, I'm talking purely in terms of the amount of turning & sideways swing the trucks & couplers can take)?

The resemblance to streetcar curves bothers me a bit too, especially because of how the curvature & thus the centrifugal force instantly jump from 0 upon entering the curve, whereas real railway curves, as far as I know, are designed such that the curvature & centrifugal force would increase/decrease gradually. Then again, according to Wikipedia streetcar curves can be as tight as 10 m, which in HO scale would be 4 times smaller than those 18" curves, and smaller than the length of most rolling stock. I personally have a hard time picturing how a streetcar can navigate a curve with a radius smaller than the length of the car itself.
« Last Edit: November 14, 2021, 01:12:08 AM by H5subway » Logged
Terry Toenges


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« Reply #19 on: November 14, 2021, 02:47:19 AM »

This is an interesting chart. I've never thought about a streetcar layout so I never looked into radii for them.
New Orleans Streetcars use 50' (6.9" in HO) on the road and down to 27' (3.7" in HO) in the yard. San Francisco uses 43' (5.9" in HO). Boston and Newark use 33' (4.55") for their light rail. New York subway is 95' (13.1"). U.S. standard rail preferred minimum for main line freight is 574' (79.2" in HO). A 10 meter curve would be about 4.5".
Japan's 314 mph Maglev is 26,247' or 3620" in HO.
https://en.wikipedia.org/wiki/Minimum_railway_curve_radius
« Last Edit: November 14, 2021, 02:53:02 AM by Terry Toenges » Logged

Feel like a Mogul.
jward


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« Reply #20 on: November 14, 2021, 01:29:22 PM »

I find the usage of curve radius in the Wikipedia article interesting, because the railroad's engineering departments invariably use the term "degree" on internal documents like track charts to express how sharp a curve is. In engineering terms, a 100 foot chord is drawn across the curve, and lines are drawn from the points where the chord intersects the track's centerline to the centerpoint of the curve (where the radius is calculated from) and the number of degrees apart these two intersecting lines are is the degree of curvature. The approximate relationship between the degree of curvature, radius, and the HO scale equivalent can be found here: http://www.trainweb.org/freemoslo/Modules/Tips-and-Techniques/degrees_of_curve_to_radius.htm




It is interesting to note that, despite what the specs are for a particular locomotive. the Western Maryland Railway was able to use locomotives up to and including GP40s on curves as sharp as 30 degrees, which scales out to about 26" radius. These locomotives were used on that line in regular service, not on a one off test train, and the railroad's reluctance to use GP40s there stems not from their size, but the inability to utilize the extra horsepower generated  at the low speeds necessary for operation on those curves. At the ten mph operating speed there, the turbocharged units were useless, and a GP38 pulled as well as a GP40 at low speed. And even those were only slightly more powerful than the GP9s, F7s, and RS3s that ruled those curves well into the 1970s and 1980s.


So, given the selective compression necessary for a convincing model railroad, using any 4 axle diesels on an 18r curve is not that far fetched.

As for trolleys, Fast Tracks makes jigs for a switch with a 9" radius curved route for those who like to build their own.
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Jeffery S Ward Sr
Pittsburgh, PA
Trainman203

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« Reply #21 on: November 15, 2021, 09:52:12 AM »

If centrifugal force is an issue when your train enters a switch you are running way too fast.
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H5subway

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« Reply #22 on: November 18, 2021, 02:05:26 PM »

Centrifugal force is not an issue per se, unless I'm doing rolling tests pushing cars with my hands, where I might accidentally give it too much of a push such that it might fly off the curve, but that's well beyond the maximum speed locomotives can run under their own power.
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Trainman203

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« Reply #23 on: December 01, 2021, 04:43:17 PM »

I was thinking of the old 0-27 curves and Lionel steam engines hitting what would be a 13” radius curve in HO at rocket speed, like those of us at a certain age all did.  Centrifugal force mattered there!  Lionel had “magne-traction” to help keep those babies on the track but it didn’t really work.  It was beyond fun to watch them wreck and Lionel understood that, built those things like rocks.

Need to start a new thread about those days of yore 65-70 years ago with those train sets.  No more fun ever had.  How can computer games even compare?
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