Compact triangular office layout with broad curves

S t e f a n Oct 18, 2020

  1. S t e f a n

    S t e f a n TrainBoard Member

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    After a slight mishap when trying to change the mounting height of my (very unfinished) small N scale layout, I decided to rebuild as a triangular 8' corner layout with 24" curves on the double mainline. The old 'L' shaped baseplate/shelf had only room for 13" radius turnaround loops.
    Here is the first draft of the layout; the bottom of the baseplate is 54" above the floor; trackwork will be code 55 micro engineering flex track and #6 ME turnouts. In the past I have mounted track on a sandwich of camper seal tape and that black slightly sticky roadbed material, but I'm open to suggestions.
    How is the Woodland Scenics foam track bed?

    office_new_20201016.jpg

    Goals:
    • I want to be able to run eight car passenger trains, as much as that is possible in a small 2nd bedroom/office type space. This means reasonably large curves, and reasonably long sidings (eight 85' cars in 1:160 scale = four feet). A double mainline might make sense, to allow to run two passenger trains at the same time.
    • I want to integrate a turntable and engine house I already have, also as a display area for locomotives and MOW equipment (e.g. a rotary snowplow/BR44 set).
    • It would be nice to leave space for future industries (e.g. I have a steel mill kit that I need to assemble).
    • I'm not sure how much switching etc. I actually want to do, but I don't want to design myself into a corner where I can't add features in the future. So the mainline layout should leave some room for extension.
    • I haven't decided yet whether I want to go vertical at all; for the mainline the emphasis should be on reliable running of long passenger trains, so that probably means staying flat.

    For now the plan is to get a running layout with some basic landscaping, and then maybe refine and add more landscaping, industry, extensions etc. later on.

    In the design above, I'm happy with the mainline length (about two times 30 feet) and the radii (mostly 24"), and with the amount of free space left.
    I'm not 100% happy with the stub end staging/storage tracks at the bottom left - the tracks could be longer, which might mean reducing the mainline radius a bit at the bottom curve -, and with the placement of and access to the turntable and engine house.
    I'm also just getting started with XtrkCAD, so I'm glad I was able to place turnouts at all. Some of the connections look a bit rough to me.

    The long diagonal has hinges at the bottom end (at the 2 foot line), which makes it easier to get to my computer desk under the northern/top shelf of the layout. I was thinking that at some point I might want to add a lift bridge at the top right end - Chicago has a prototype just south of the Amtrak facility- , but the tracks for turntable access collide with that idea right now.

    I would appreciate feedback on the general idea, and on the layout draft. I have built the benchwork/baseplate/shelf including the diagonal.
     

    Attached Files:

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  2. S t e f a n

    S t e f a n TrainBoard Member

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    A few pictures of the benchwork, in particular of the hinged diagonal lift section.

    The hinges: the rail heads need to be below the hinge pin axis, so that rail separation increases as the lift section opens.

    Shelf support: unfortunately the walls are double drywall over plaster-covered slats nailed to the studs, so it is quite difficult to screw into the studs. The right most bracket is attached to a stud. The same construction held up a much heavier solid wood base board.

    Shelf and lift section support: the turn buckle hung from a steel wire strung between a door and a window frame seems to work quite well to level the bench work.

    The lift section pulley attached to the horizontal steel wire:
     
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  3. Shortround

    Shortround TrainBoard Member

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    Some interesting ideas there. When I can get to it I have a 10'x10' area. At the entrance is a closet, door and 3'x4' extension area. Or use it for the computer. There's power and tv cable access there. I have the single layer drywalls but I don't think the landlord wouldn't agree to punching all the holes so it will have to be mounted on cabinets and shelving units.
    I would be interested in seeing a fuller description of the lift up section. I will need that near the closet and computer area.
    Richard
     
  4. S t e f a n

    S t e f a n TrainBoard Member

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    A few links:

     
  5. BoxcabE50

    BoxcabE50 Staff Member TrainBoard Supporter

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    If simply being used to attach roadbed to underlayment, or track itself, have you ever tried carpet tape?
     
  6. S t e f a n

    S t e f a n TrainBoard Member

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    Hi Boxcab50, no, haven't used that yet. It's a fiber reinforced double sided tape with extra strong grip? What I like about the camper seal tape is that the grip is strong, but not too strong. I can remove it using a spackle, although I haven't tried removal from the glass fiber facing of the foam board. Probably even a weak glue will take off the paint layer and the top layer of fibers.

    In the past I have used cork roadbed, adhered on both sides (baseplate and track) with latex glue, and the camper seal/black rubber AMI instant roadbed combination. I found the AMI black rubber stuff a bit easier to work with, but t seems AMI is out of business, so I'll have to come up with something new.
     
    Last edited: Oct 19, 2020
  7. Shortround

    Shortround TrainBoard Member

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    Carpet tape works nice but the camper seal tape will add a little soft cushioning I think. It may soften the noise as well as hide irregularities.
    Just my opinion.
     
  8. BigJake

    BigJake TrainBoard Member

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    24" curves will make your passenger trains look great!

    But the S curves at about the 6' mark, and again at the 8' mark on the left side, even with 24" radii on both sides, will be roughly as severe as a 12" radius transition directly to straight.

    It may not affect operations, but it may make those long passenger cars look more like toy trains.

    Broad, gentle S's can really show off a train and the scenery, but less might be more in this case.
     
  9. S t e f a n

    S t e f a n TrainBoard Member

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    BigJake, I'm not sure which way I want to go in that area; I looked at a layout variant with straight track there, but I was afraid all straight track between the three main line curves would be too boring. I should try to make the S a bit less pronounced, if I can figure out how to get XtrkCAD to do that.

    Other changes I'm thinking about:
    1. I'm thinking of moving the main double loop one or two inches to the right, and starting the first of the stub tracks already around the 6' mark, to make it longer and suitable for staging a whole passenger train. I will probably have to reduce the bottom end main line curve radius a bit (towards 20") to make space for that.
    2. I'm not sure how useful the shorter stub tracks really are; maybe fewer but longer tracks are better? In the current design (above) the center stub track forms part of a wye; but the track itself is much too short to turn a whole train around (it is 1' long; I'd need about 5').
    3. I'm not sure whether I want to move the long siding along the top wall to the inside of the double track mainline, and then access the turntable area from that siding. Having fewer turnouts on the main line seems an advantage.
    4. I could also try to keep the gap between the wall at the top and the tracks a bit larger, either for scenery (thin relief/front only passenger station?), or to allow future expansion. But the space I have overall is pretty limited, so there is an argument to be made for going as close to the wall as possible with the mainline, to maximize the track length available for running.
     
  10. BigJake

    BigJake TrainBoard Member

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    Oh, I would definitely keep an S curve there, just make it a little more gentle. Two long trains, passing each other through a gentle, double-track S are very photogenic! Especially along the side, where you're viewpoint if from ahead/behind, not broadside.

    I use a formula to judge the relative severity of an S transition between two radii, R1 & R2, compared to a given radius, Requivalent, transitioned abruptly to straight track, with no easement, as follows:

    Requivalent = 1/(1/R1 + 1/R2)​

    The formula correctly predicts a transition to straight (infinite radius of curvature) as being unchanged (just that of the remaining curve). If you have a transition between two curves in the same direction, just subtract one of the reciprocals, instead of adding. Since I use sectional Unitrack, I use this formula (w/subtraction) to predict effectiveness of a longer radius curve section, in lieu of a proper easement, between the curve and the straight.

    I worked this formula out on my own many years ago, but I wouldn't be surprised at all if someone else beat me to it.

    If the formula looks familiar, it is the same one used for calculating the equivalent resistance of two resistors connected in parallel.
     
  11. S t e f a n

    S t e f a n TrainBoard Member

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    I guess this formula computes the equivalent radius for the angular offset of the trucks, which in turn also determine the overhang of the car body. Makes sense.

    I assume that similarly easements should be linear in 1/R? That would make the radial acceleration increase linearly from 0 on the straight track to the constant value at constant radius.
     
  12. BigJake

    BigJake TrainBoard Member

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    1:1 railroads use banked (aka super-elevated) curves to deal with radial acceleration when necessary, just like highways and race car tracks*. An easement is used to manage the transition in banking, as well as the offset between coupled cars due to changing curvatures. Combining an easement with gradually increasing banking would fool a pendulum, but does not fool a gyroscope.

    IINM, 1:1 railroads measure curvature as so many feet of change in direction over so much distance.** 1/R may not be exactly that, but it does match and work at both extremes (straights and perfectly mitered, zero-radius corners.) I haven't done the math to see if both methods are equivalent, but 1/R is an easy way to at least approximate it, even if it may not be perfect.

    *NASCAR, INDYCAR and Formula 1 obviously have different ideas on the merits and extents of mitigating radial acceleration for the driver/car, let alone actually having to turn in both directions. Don't get me started... but let's just say that I like them all, on road courses! And running 2/3rds of the course on an oval, with a few squiggles through the infield doesn't count! Maybe that's why I'm a sucker for folded dogbone layouts...

    **This method of measurement may have been more practical when laying out curves in rugged terrain, where the center of curvature may have been inaccessible.
     
  13. S t e f a n

    S t e f a n TrainBoard Member

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    Hi BigJake, thanks! I have built eased and banked curves before, but I just eyeballed them. Your formula got me started on thinking what actually the point of easement might be: I assume the goal is to build up lateral acceleration (the amount not compensated by banking) and truck rotational acceleration slowly. In math parlance, avoiding jumps (discontinuities) in the second derivative. This will also minimize offsets between cars, which one could think of as moving 'integrators' or discrete samplers of the track direction (it's getting a bit theoretical here - I don't want to lose my model railroader license by violating the rule against overthinking...).

    Of course, getting XtrkCAD to do all this is another problem. And then properly transferring it to the benchwork. I'll probably just continue eyeballing it.

    Regarding the 'degrees of direction change per 100 feet' curvature measure, I had heard about it, and actually recently read a bit more; I think it was in a thread on this forum.

    Ok, I should get back to making some adjustments to my layout plan. The good news is that so far the benchwork has not fallen down, and I bumped my head into it only a few times.
     
  14. BigJake

    BigJake TrainBoard Member

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    I'm not aware of a previous post, but I'm not sure if the offset per 100 feet is in degrees or feet. Either can be converted to the other.

    Hey, I use longer radius sectional track to create an ersatz easement, so what do I know about real easements?!

    Avoiding "large" (whatever that is) step changes in radius (including from positive to negative radius, e.g. changing direction in S curves) is the goal.

    "Large" depends on equipment length, length from truck pivot to coupler, coupler mounting (long or short shanks, body or truck mount, etc.). Most N equipment will function down to 9.75" radius, including transitions directly from straight to that radius. Note that "function" (i.e. not derail or uncouple) and "looks good" are two different things!
     
  15. S t e f a n

    S t e f a n TrainBoard Member

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    Progress with the track plan:
    • fixed roundhouse dimensions (part was too small), relocated roundhouse & turntable, moved siding
    • increased length of first yard track to allow staging of 5' passenger trains
    • all yard tracks are now at least three feet long
    • added lead track for five left (clockwise connected) yard tracks; runaround track and lead for three right (counterclockwise connected) yard tracks still missing
    • relocated long siding (8') between mainline tracks: allows sharing without crossing other main
    • minimum mainline radius is 22.5"
    • created structure footprint for Walthers blast furnace
     
    Last edited: Oct 25, 2020
  16. BigJake

    BigJake TrainBoard Member

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    Much improved!

    Now let's look at some operational challenges...

    Do you really need two leads to the roundhouse, both directly onto mainline trackage, rather than sidings? I'm trying to visualize when/how the lower/right roundhouse lead would ever be used effectively.

    An engine on the upper/left roundhouse lead must (briefly) travel on a mainline track to get to the siding for water/fuel/sand(?). And then it needs a few saw-back moves, across the mains no less, to get to the yard's apparent arrival/departure track. The access to the yard is not any better via the lower/right roundhouse lead, and it would bypass fuel, water and sand resources on the other side of the layout.

    Since there is not enough room for the roundhouse on the outside of the main loop, or the yards on the inside, perhaps you should consider an elevated main for the left and lower portions of the layout. This would provide better access between round house, service, A/D and more/longer yard tracks, passing underneath the elevated main's curve at bottom.
     
  17. S t e f a n

    S t e f a n TrainBoard Member

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    Now there are two of you arguing for the elevated mainline, if I include the little voice in my head....

    I have thought about ducking under the mainline with the yard tracks. Before going into the center of the room with the diagonal that would have been the only way to build useable yard tracks. I'm just not sure how reliable I can build that trackwork, especially since I want to run long equipment and relatively long trains on the mainline. Currently I'm still trying to see how far I can get staying at one level.

    But you are absolutely right that the terminal and yard operation could be improved; right now all of that is playing second fiddle to the mainline running. The yard is a serious compromise:
    • no runaround track
    • no caboose track
    • the last two feet of the yard are actually out of manual reach; it's thus mainly a storage yard
    • the locomotive service facilities are not even there yet
    One argument (besides my doubts regarding reliable operation) against vertical transitions is that they would take up most of the linear space available on this small layout: to achieve the absolute minimum of 1.5" of vertical clearance at y=4' with a 2% grade, I have to start the transition 50*1.5"=75" or more than 6' away from there; that puts the yard access from the mainline almost into the top center area. This would be doable, but it would also be nice to leave some space for smaller industrial sidings, and not use it all for the yard.

    But most of all I fear going vertical makes the layout a lot more complicated to build. Maybe best left for a later rebuild, once I know that this benchwork concept actually works.

    Any thoughts on that mess of switches at x=1',y=6'? It's not even all that functional; there is no crossover from the yard or the outer main going clockwise. I'm still not fully proficient with XtrkCAD, so it took me a while to get all the connections to line up.

    One more thought: the longest straight section is on the diagonal, so it is tempting to put more functionality there (yard access, passenger station, services...). But that is also structurally the weakest section, so I want to refrain from overloading it. Even ballast weight does add up...
     
  18. S t e f a n

    S t e f a n TrainBoard Member

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  19. BigJake

    BigJake TrainBoard Member

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    I was assuming the orange structures at top were engine service facilities.

    I think either of the two new locations for the roundhouse are preferable, since they were usually located closer to the yard, and any industries at top (and/or at bottom, depending how wide your yard will be), would be better separated from the yard, at least by access, if not by physical proximity.

    Difficulty of build has more to do with what type of construction you were planning. If you have a flat base, and use the Woodland Scenics inclines/risers, it's not difficult at all. Not much more difficult if you have a thin plywood top, and cookie-cut it. If you were planning on spline benchwork, well, then that can get more complicated.

    You could also build a flat mainline loop, with ramps down to the yard/roundhouse/etc. level. Whether you put the industries on the mainline level, or below on the yard/etc. level.

    You could also think about having a sloped but otherwise flat main bench, with a "dropped" area (to horizontal) for the yard, etc.

    I assume when you say "track work" you mean bench/terrain work... Unless you are planning on hand-building the bridge(s) over the yard, the track work should not be affected.
     
  20. S t e f a n

    S t e f a n TrainBoard Member

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    Didn't see your post until now! Your 4th point is pretty much the conclusion I have come to: build a flat main loop, but 2" above the base plate. I was looking at the woodland scenics inclines and risers, but it seems a bit like a copout. I should be able to do that myself.

    I do like the original (top right) roundhouse location, since it allows adding a second six stall unit.

    Scratch building bridges, track work etc.: Funny you'd mention it. I took a a lot of pictures of the PRR vertical lift bridge (Canal Street bridge, or PRR bridge #458), and looked at both Plastruct and Evergreen for materials. Turns out people have scratch built this bridge in HO (http://cs.trains.com/mrr/f/88/t/276254.aspx), reducing the number of different lattice patterns a bit (the prototype seems to use four or five different composite beam types). But a project of that complexity is probably better left for later.
    On the other hand, scratch building the viaduct across the yard using those same materials (or using bridge kits) seems more straightforward.

    A question regarding the inclines from and to the yard and the roundhouse: My current thinking is to have two long (8' or so) shared sidings between the main lines, at the 2" level, and drop down from those sidings to the yard & roundhouse level (0"). It would minimize the number of main line turnouts, since base level access would be through the beginning of a long siding that in turn has access to both mainlines, not directly. Does that sound reasonable?
    I should probably post a sketch, but haven't made one yet. I'm sure glad I'm using XtrkCAD; doing all these variations on paper could get tiresome pretty quick.
     

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