Radius and modern diesels/passenger cars

Mopar4wd Oct 29, 2018

  1. bremner

    bremner Staff Member

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    9.75" radius=130' radius
    11" radius=146' 8" radius
    17" radius=226' 8" radius

    a REAL F7 minimum radius is 274', which is 20.55" in N Scale.
     
    mtntrainman likes this.
  2. acptulsa

    acptulsa TrainBoard Member

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    Lionel could have taught General Motors how to install a pilot that turned with the front truck. That might have gotten that radius down to an O31-like 62'.

    GM might have scoffed at that. But Lionel did sell more F-3As than EMD did.
     
    BarstowRick and bremner like this.
  3. Maletrain

    Maletrain TrainBoard Member

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    Well, if you are modeling street scenes in a city, then tight curves can even look right. Those little 0-4-0 "Docksider" steam locomotives were really designed for curves as tight as 82° at slow speed, which is about 5½" in N scale. They were limited to what amounts to 8½" at "normal speed," but even that speed is a creep, compared to toy train speeds. By the time you get to an 0-8-0 switcher typically used in a yard, the minimum curvature for normal speed would be about 36" in N scale, and still about 27" at "slow speed."
     
  4. John Moore

    John Moore TrainBoard Supporter

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    While most folks are struggling to get maximum radius I have gone the other direction to get minimum radius. After research with various locos that are currently available I came up with a selection that would run well at slow speed on 7.75 and 8 inch radius. That research project was posted to this board several years ago. Completely down sizing in my golden years was the goal to end up with a smaller more manageable layout. When it came to passenger equipment I settled on a 35 to 40 foot passenger car as desirable for my layout that was to be built to a narrow gauge flavor but staying with a standard gauge track. The first Turtle Creek Central was built to those standards with the tight curves and proved successful in operation, My passenger fleet was made up of older clerestory roofed 60 and 65 foot cars which fit my modeling era. Some of those cars were cut down longer cars.

    Continuing to look for a shorter passenger car I discovered the Japanese Bandai B Train cars and then developed some trains using a model that closely resembled mini RDCs with cars only about 30 foot in length. Since I also wanted to stay with a point to point operation and eliminate wyes and turntables I have cab cars at both ends and have a push pull operation. So today I have short 3 and 4 car passenger trains operating on the new Turtle Creek rebuilt after my move. The first part of the new layout is set on a 36 inch wide HC door with the track all located so that it is withing a 30 inch reach with maximum 8 and 9 inch radius.
     
    SP&S #750 likes this.
  5. Mopar4wd

    Mopar4wd TrainBoard Member

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    Depending on what your modeling you do find some tight radius's in the real world. The electric interurban freights had some tight ones. The you get into Trolley lines which could be really tight. I forget the exact radius but I think the Trolley Museum in East Windsor CT has a curve that's under 150' radius. which gets you pretty close to the 9.75". But yeah for mainlines nothing like that. One of the tightest I can think of on a high speed mainline is In New London Ct and I think that's still around a 1000' radius.
     
  6. Calzephyr

    Calzephyr TrainBoard Supporter

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    Most N scale model passenger cars are created to work on 9-3/4 or 11 inch radii if the couplers are far enough away from the frame to prevent binding. The fixed couplers (not attached to the trucks) on the six axle locomotives could be a problem unless they are medium-long shank types. Those don't look well and coupling distances are usually unacceptably far apart. Furthermore... on anything less than 12" radii... the overhang on curves could interfere with any nearby scenery or roadside structures (signals, signage etc.). Most N scalers prefer greater than 15" radius and 19" is best for longer rolling stock including passenger equipment. You may be able to get away with short segments of curves less than 12" radii in certain areas.
     
  7. bill pearce

    bill pearce TrainBoard Member

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    As a result of the unrealistic 9 3/4 inch radius truck mounted couplers are required. To get coupler swing possible, models must sit higher off the truck than in real life. Body mount the couplers, eschew tight radiuses and you can lower the carbodies and things look worlds better
     
  8. dualgauge

    dualgauge TrainBoard Member

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    Have Kato's Broadway Limited And E8's. lead car kept derailing. The problem was the front coupler on E8 did not have enough swing. Use rear coupler, which is truck mounted gives no problems. This was on 20+ curves.
     
  9. BarstowRick

    BarstowRick TrainBoard Supporter

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    Allow me to think this through out loud. Are we talking 20" radius curves or 20" diameter curves? Or are you talking 20mm curves as provided by Kato. There is a difference.

    Keep in mind tighter radius curves bring out the worst as in problems with your long E8's and full length passenger cars. With Kato's passenger cars the couplers are truck mounted. Teaming them up with a body mounted coupler, may not be the best thing. The body mounted coupler tends to pull the truck of the passenger car, off the rails/derail.

    I hope that helps.
     
  10. dualgauge

    dualgauge TrainBoard Member

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    20" radius curves. On my Kato E8A nose coupler does not swing far enough.
     
  11. BarstowRick

    BarstowRick TrainBoard Supporter

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    Good come back. You may want to consider replacing the Kato Coupler with a Micro-Trains coupler 2150 comes to mind . I need to go back and double check which one I put on so I don't miss-inform you. Headed out for a supper date. Back at you when I get home.
     
  12. acptulsa

    acptulsa TrainBoard Member

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    You might also consider a body mounted coupler. I prefer them because it's hard to back a train with truck-mounted couplers. If you don't want to convert the whole consist to truck-mounts, consider converting one end of the lead baggage car. That will fix it.
     
  13. BarstowRick

    BarstowRick TrainBoard Supporter

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    That fixed the problem on one of my passenger trains headed up by E8's, Southern Pacific, Daylight, Passenger trains. I can negotiate 15" radius curves in a reverse move, slowly but nothing tighter.
     
  14. dualgauge

    dualgauge TrainBoard Member

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    Thank you for that information. Will try.
     

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