Question Rokuhan R70/95 layout

Raytl Jan 28, 2016

  1. Raytl

    Raytl TrainBoard Member

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    Hi All,

    I was thinking of adding Rokuhan's plan A to my layout as a kind of trolley route. There are no trolleys that I know of in Z, so I'm leaning towards a Marklin Railbus. Just curious if anyone else has suggestions on locos that might run on these tight turns and also any thoughts on using a loco to make a trolley?

    Here's a link to the plan:

    http://www.rokuhan.com/english/layout/index.php

    Best,

    Ray
     
  2. SJ Z-man

    SJ Z-man TrainBoard Member

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    The Railbus might be OK. I would test one on the 70mm track first. The longer wheel base might bind on the smaller radius. The typical märklin short freight cars will easily do this radius and smaller but the locos likely get more difficult, unless 0-4-0 steam. Loren's Silverware set with ~3.5 radius (90mm) was about the limit.

    Maybe 2 linked together, a more common site.
     
  3. Raytl

    Raytl TrainBoard Member

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    SJ, just realized I had not responded to you. Thank you for the reply.

    Best,

    Ray
     
  4. tracktoo

    tracktoo TrainBoard Member

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    Would there be a market for a Z trolley? Maybe a PCC?
     
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  5. Raytl

    Raytl TrainBoard Member

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    I would like a trolley, not sure of others. Seems like it would be a neat feature for a town/city. I have seen some small motors without shells being sold on Z Scale Monster and have wondered if you could 3D print a trolley body to attach to it. PCC would work too.
     
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  6. Heay Equipment Designer

    Heay Equipment Designer TrainBoard Member

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    There are few hurtles to overcome if you want a PCC trolley in Z. I worked out a chassis on paper that uses the only motorized chassis available in Z that I know of right now. Since the motor is so long, the smallest radius you could have that still allows the motor articulate in the PCC shell is a 195 mm. In the real world I would say 70 to 90 mm would be closer to the real thing. These trolleys have long articulating drawbars that the couplers are mounted to so they can go around a really tight radius. Another problem for scale is distance between the wheels on the truck of the Power Max motor, its way to long for proper scale. So you will need to modify the chassis of the Power Max motor. I believe it uses a worm gear so this would in theory be possible to do. But I have never opened up a power max motor before. Last but not least, the wheels are way, way, way to big... PCC trolleys have 26" diameter wheels if I remember correctly. If you could find 30" wheels, you could probably get away with it. But I have never seen anything that small in Z. But if you have a micro lathe, you could probably turn your own. So I dont think its impossible but it wont be easy.

    Thanks,

    -Jon
     
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  7. CJT

    CJT TrainBoard Member

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    here is a short video of engines running on 8", 10", 12" oval. all three will run on the 8"
    I'm thinking that the 8" is the R70

     
    Last edited: May 8, 2016
  8. Garth-H

    Garth-H TrainBoard Supporter

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    this is an oval of R70 with train running on it and it is much less than 8 inches across. It is about 4 inches or less this oval is about 8 inches by 4 inches in sixe.
     
  9. CJT

    CJT TrainBoard Member

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    I though that r45 was the smaller track. in this track plan it shows r70 =210mm or 8"

    now I'm confused
     

    Attached Files:

  10. markm

    markm TrainBoard Supporter

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    r45 is 45mm/25.4 mm/in = 1.77 inches r70 is 70/25.4 = 2.75 inches. The 210mm measurement in the drawing suggest the outer loop would be R95 (190mm + track width). The 460mm horizontal measurement suggests the same (190mm+245mm+track width). If you calculate the size and placement of the inner track work, it's greater than 140mm. So I think there is an error in the layout.

    Mark
     
  11. pmx

    pmx TrainBoard Member

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    I would also like to point out that the "R" in the part is for radius, so a semicircle of R70 is 140mm. And would agree with Mark that there is a error as the overall dimensions do not match with the sums from the track, which is 140mm [2 x 70 mm R] x 385mm [70mm R+25 mm+(4 x 55 mm) + 70 mm R]

    ~Paul E
     
  12. CJT

    CJT TrainBoard Member

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    Thanks for explaining that guys. the smaller track I showed is the R95

    the track Garth showed is R70
    Nice engine Garth would that run on the R45 track?



    Thanks

    Chuck
     
  13. markm

    markm TrainBoard Supporter

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    Chuck,
    Glad to help. I went back to the Rokuhan site and the parts list for the layout calls for R95 track. For me, the esthetic issues of tight curves comes into play before the mechanical. The train in Garth's video fits the size of the curves. Compare it to the inner track in your video where the locomotive extends unrealistically over the road bed.

    Mark
     
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  14. markm

    markm TrainBoard Supporter

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    Chuck,
    Glad to help. I went back to the Rokuhan site and the parts list for the layout calls for R95 track. For me, the esthetic issues of tight curves comes into play before the mechanical. The train in Garth's video fits the size of the curves. Compare it to the inner track in your video where the locomotive extends unrealistically over the road bed.

    Mark
     
  15. CJT

    CJT TrainBoard Member

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    Yea i get what your saying , but for me its fantasy, imagination and compromise . I wish i had a large space to make large curves, but i have only 22"x 36"for my main layout and would like a couple smaller layouts. I like this Rokuhan track and run large engines not just switchers. Marklin engines seem to take the sharp curves better than other brands. again compromise the f9 with those big wheels . maybe that's why they are off scale so that you can run them on small tight layouts. I am happy with my layout and my 2yr old really loves it. Now to start a new layout with this r70 and r95 track to create something on 22"x 26" layout
     
  16. Heay Equipment Designer

    Heay Equipment Designer TrainBoard Member

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    Here is some real world trolley track inspiration. WWII era PCC's are still running by my house at the Mattapan station on the Milton line outside of Boston. Each PCC car comes out to be about 46 ft and the diameter of the turnaround circle is about 2.5 cars. So 2.5 x 46 = 115 feet. 115 x 12 = 1380 inches. 1380 inches / 220 inches = 6.272 inches. 6.272 x 25.4 = 159.327 mm diameter circle. Divide that in half to get the radius and you are looking at what would scale down to basically around an 80 mm radius curve in Z scale.

    The beauty of these PCC cars are that even at only 46 feet long, the trucks are recessed way in to give them a really short wheelbase. Add to that, the drawbar the couplers are attached to can swing the coupler all the way from one outside edge of the trolley to the extreme other. The articulating drawbar allows these cars to go around really tight curves and the body swings way out without the cars becoming uncoupled from each other. Its pretty neat to see a set of these go around such a tight radius curve and very noisy from all the friction....

    Thanks,

    -Jon

    PCC.jpg
     
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  17. Raytl

    Raytl TrainBoard Member

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    Very cool, I like the PCC station photo. I emailed the Searails guys. Sounds like they've done a prototype trolley, but marketing one for mass consumption would be difficult (lots of trolley/PCC variations and a very small market to sell to). They could custom build something, but I would need to nail down exactly what I want to get a price estimate.
     
  18. tracktoo

    tracktoo TrainBoard Member

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    Those are the same issues encountered in N Scale with the difficulty multiplied in Z. I have been doing the preliminary work on just such an animal in N Scale as an extension of a project making a really small power chassis for a narrow gauge N chassis (Z track) underground mine locomotive project. The N scale PCC will be started in the not so distant future and it seems like I will have a small enough chassis to accomplish the performance and more in N and then, with what I've been learning there, I feel I will be able to accomplish enough of this in Z to make something at least acceptable in Z. The turning radius is a big one. It is accomplished by having the motor as part of the power truck therefore not requiring a universal drive to swing the tortured angle required to get the turning radius. Therefore the turning radius will be dictated by the body and wheel clearance only. Another problem you've identified is the wheel diameter but that isn't just the wheel, which could be made easy enough, but it's also the final drive gear size that has to be less than the wheel diameter to clear the rails, especially at switches and crosses. That's a problem in available equipment and like the wheel, isn't just making the gear small enough which is its own challenge, but at the same time accomplishing a sufficient gear reduction in a device that small that delivers manageable speeds, not a top fuel dragster on takeoff.

    One thing you could do with existing equipment and has been done is to make a four wheel old time trolley using a device like the Searails but it will be projecting up into the passenger compartment pretty much consuming the whole interior. In Z I may not be able to avoid that entirely but what I am making for the Nn3 and N Scale chassis is already over 30% lower profile than the Searails and I may still be able to go more while still maintaining very appropriate N scale speeds. It's a work in progress but 25 final chassis' for final testing for the mine loco is underway right now and then the trolley power truck and chassis work will be following. If this is something anyone would be interested in for a distant future project you could send me a PM and I will start a list of those who would like to receive any updates. No, there will be no pre-orders. We'll just make them and have them for sale. :cool: I guess these days that makes us old school. :)

    A few PCC prototype dimensions that may prove helpful:

    Wheel Dia: 26" +/- 1"
    Truck Axle C/L: 6'
    Truck C/L: 22'9"
    Minimum Turning Radius: 35'
     
  19. Garth-H

    Garth-H TrainBoard Supporter

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    I have not tried it on R45 but if it did work it would be very tight as this is 3 axles, I know the Searails Power max will run on R45.

    Rokuhan measurements are all metric and R is for Radius to the center line of track curve. The track is on roadbed that is 15 mm wide to to get at width of an oval, double the radius and add 15 to it then convert to inches by dividing by 25.4, mm and that gives the following:-

    R270 = 21.25 in. , R245 = 19.3 in., R220 = 17.9in., R195 = 15.4 in., R170 = 13.4 in., R145 = 11.40in.k R120 = 9.4 in.k R95 = 7.4 in.k R70 = 5.1 in. ; For dimensions of an oval add up the straights on a side and then add the diameter of the curved track used, then divide by 25.4 to get inches, works for width and length. hope this helps in your planning.
     
  20. Garth-H

    Garth-H TrainBoard Supporter

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    In my early days in n I modeled trolleys in N Scale we made chassis in a similar manner to the Searails power max. the original design I copied was found in 3 places, One was MR or MRC article on a N scale trolley , the other was the 2MM association in the UK ( very good source of building tips and tricks for power units and other things as well as a parts source as this group hand crafts their equipment) and the third was in a Japanese magazine and this was in the mid to late 70's the idea was to use a pager vibrator motor with Mod 2 gears, the two axles had a gear in the middle to match the worms used to drive them the motor was located above the center line o f the truck and rubber belt drive or a gear drive from motor to the a drive shaft below the motor in line with the motor and with two worm mounted to match the distance between the two axles. The side rails were made of right angle pieces of brass with slots for the axles and the slots were wide enough to take brass tubing which acted as the bearing sleeve for axle. The two angle pieces were soldered to a piece of PCBoard with copper removed by a saw cut between the two angles, for split rail pick up. The forward truck was a copy of the power truck with no drive so 4 axle pickup and split frame motor isolated from track so it could be set up for track pick up or pole to over head wire and track return. Now you need a floor to connect two trucks and a 3d print body to go on top. I N scale at the time we were casting with resin using master made in styrene creating rubber molds as there was no 3d printing.
    I later years I used Tomix Tm power chassis to create doodlebugs in Nn3 or Nn42 as the truck could be modified to run on 6.5 mm gauge track, I can point you to a web page which shows how to do this, but I think it is a bit too big for Z, wheels are over sized, not sure if any of trolley chassis can be narrowed like the TM series of chassis, I used. A mini RC car could be considered for part source, small motor and gears, I can find them here for under 10.00 bucks.
     

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