The cross-sectional profile in my initial post (below) shows a "representation" of what an open helix would look like at 0", +3", +6", and +9" elevations. The "blocks" represent various rolling stock profiles as they would look on the track:
The minimum radius of the inside curve would be R31" and max out @ R36" @ +9" elevation.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
if the radius is increasing and the grade is constant, how can the height differences be the same
greg - Philadelphia & Reading / Reading
gregc mbinsewi I'm still trying to put together a 3d image height assuming 2% grade
mbinsewi I'm still trying to put together a 3d image
height assuming 2% grade
Greg, look at Tom's track plan.
Trackage leaves the staging yard at elevation 0, after crossing under the helix tracks the grade starts. When it gets back around to the yard lead it crosses over at +4.73. It continues around again and crosses over the yard lead again at +9.0" and then levels off.
I have not established the scale of the drawing or checked the run to verify the grade - I trust Tom's work.
Sheldon
gregc if the radius is increasing and the grade is constant, how can the height differences be the same
It can't, Tom never really said that. You are over thinking this - The stair step drawing is illustrative, not the actual dimensions that will pay out in construction.
I used SolidWorks (in sketch mode) to draw up the plan and to tell me the length of each segment of straight track. Knowing the radii and angle of each curved segment, I calculated their individiual lengths using arc length formula [2πr(Φ/360)] in an Excel table. I then created another Excel formula to see how much length of track was needed for grades of 1.5% & 2%.
tstage I used SolidWorks (in sketch mode) to draw up the plan and to tell me the length of each segment of straight track. Knowing the radii and angle of each curved segment, I calculated their individiual lengths using arc length formula [2πr(Φ/360)] in an Excel table. I then created another Excel formula to see how much length of track was needed for grades of 1.5% & 2%. Tom
Wow - I would have that fiqured out the old fashioned way before I got Excel open and started to remember how to use it...... but that's just me.
rise / % = run
rise / run = %
run x % = rise
I learned some CADD years ago, have not used it in decades. Still designing houses with paper and pencil. Just landed another large residential design project last night.
tstageI used SolidWorks (in sketch mode) to draw up the plan and to tell me the length of each segment of straight track.
# ang 0, ht 0.0, rad 30.0 # ang 360, ht 3.9, rad 32.0, gr 1.96 # ang 720, ht 8.1, rad 34.0, gr 1.96 # ang 1080, ht 12.6, rad 36.0, gr 1.96 # ang 1440, ht 17.2, rad 38.0, gr 1.96 # ang 1800, ht 22.2, rad 40.0, gr 1.96
gregc tstage I used SolidWorks (in sketch mode) to draw up the plan and to tell me the length of each segment of straight track. if the height differences are the same between each level as the radius increases with height then the grade decreases
tstage I used SolidWorks (in sketch mode) to draw up the plan and to tell me the length of each segment of straight track.
if the height differences are the same between each level as the radius increases with height then the grade decreases
Greg, again, I don't think Tom meant to imply that the dropoff from each track to the next would always be exactly equal at every point. And that has no real bearing on his question or the design as a whole.
Grades are never perfect rates of climb anyway, you have vertical curves in and out, and on the prototype you may havea number of constantly changing "actual grades" as you progress.
And that's great, Sheldon. Nothing wrong with that. I'm a bit old school myself as I still like to know and understand the actual formula before using any sort of calculator.
What I didn't relay very well about using the Excel table was that I created a formula for tell me the accumulative rise of the helix as I added individual straight & curved segments to it. That way I could see the exact elevation at each transition point - i.e. straight section going into a curve or vice versa. If the radii or angle were readjusted, it would quickly update the information. I could also compare at a glance where the elevation was for each grade at each point.
gregc tstage I used SolidWorks (in sketch mode) to draw up the plan and to tell me the length of each segment of straight track. if the height differences are the same between each level as the radius increases with height then the grade decreases # ang 0, ht 0.0, rad 30.0 # ang 360, ht 3.9, rad 32.0, gr 1.96 # ang 720, ht 8.1, rad 34.0, gr 1.96 # ang 1080, ht 12.6, rad 36.0, gr 1.96 # ang 1440, ht 17.2, rad 38.0, gr 1.96 # ang 1800, ht 22.2, rad 40.0, gr 1.96
We get that, but the helix in question is not a circle, so it get even more complex - complex in a way that does not matter. So in the straight portions the offset will stay the same, then change in the next curve, etc - OR the grade will change.
Neither one is goingto effect the outcome here.
ATLANTIC CENTRAL I don't think Tom meant to imply that the dropoff from each track to the next would always be exactly equal at every point.
tstageThe cross-sectional profile in my initial post (below) shows a "representation" of what an open helix would look like at 0", +3", +6", and +9" elevations.
ATLANTIC CENTRALGrades are never perfect rates of climb anyway,
tstage And that's great, Sheldon. Nothing wrong with that. I'm a bit old school myself as I still like to know and understand the actual formula before using any sort of calculator. What I didn't relay very well about using the Excel table was that I created a formula for tell me the accumulative rise of the helix as I added individual straight & curved segments to it. That way I could see the exact elevation at each transition point - i.e. straight section going into a curve or vice versa. If the radii or angle were readjusted, it would quickly update the information. I could also compare at a glance where the elevation was for each grade at each point. Tom
Tom, I get all that, but in my 50 years of building layouts, calculating grades to that fine a point in advance is folly. All that matters is total run vs total rise and then good smooth vertical transitions and a smooth grade in between.
ATLANTIC CENTRALWe get that, but the helix in question is not a circle
ATLANTIC CENTRAL tstage And that's great, Sheldon. Nothing wrong with that. I'm a bit old school myself as I still like to know and understand the actual formula before using any sort of calculator. What I didn't relay very well about using the Excel table was that I created a formula for tell me the accumulative rise of the helix as I added individual straight & curved segments to it. That way I could see the exact elevation at each transition point - i.e. straight section going into a curve or vice versa. If the radii or angle were readjusted, it would quickly update the information. I could also compare at a glance where the elevation was for each grade at each point. Tom Tom, I get all that, but in my 50 years of building layouts, calculating grades to that fine a point in advance is folly. All that matters is total run vs total rise and then good smooth vertical transitions and a smooth grade in between. Sheldon
Agreed, Sheldon. The table was only used as an exercise to give me a general idea where the elevation would be at any given point on the layout. I will not be holding to that fine a spec should I actually create the helix.
gregc ATLANTIC CENTRAL We get that, but the helix in question is not a circle it's a spiral. i summed the lengths of each 2 deg segment
ATLANTIC CENTRAL We get that, but the helix in question is not a circle
it's a spiral. i summed the lengths of each 2 deg segment
It's not a spiral, it has straight segments. Did you look at the plan posted earlier in the thread?
Why is it so hard to understand that the 3" offset is not carved in stone, only representitive of the concept.
Too much theory going on here, not enough practical civil engineering.
tstage ATLANTIC CENTRAL tstage And that's great, Sheldon. Nothing wrong with that. I'm a bit old school myself as I still like to know and understand the actual formula before using any sort of calculator. What I didn't relay very well about using the Excel table was that I created a formula for tell me the accumulative rise of the helix as I added individual straight & curved segments to it. That way I could see the exact elevation at each transition point - i.e. straight section going into a curve or vice versa. If the radii or angle were readjusted, it would quickly update the information. I could also compare at a glance where the elevation was for each grade at each point. Tom Tom, I get all that, but in my 50 years of building layouts, calculating grades to that fine a point in advance is folly. All that matters is total run vs total rise and then good smooth vertical transitions and a smooth grade in between. Sheldon Agreed, Sheldon. The table was only used as an exercise to give me a general idea where the elevation would be at any given point on the layout. I will not be holding to that fine a spec should I actually create the helix. Tom
You need to explain "general idea" to Greg.
all i tried to do was provide a a 3d image of what was being proposed
gregc all i tried to do was provide a a 3d image of what was being proposed
OK, it took me a few minutes looking at his drawing to get the whole thing myself.
But it is not a circular spiral, the difference between each level will not be consistant, and all mathmaticly calculated grades are aproximate.
Personally, I don't need 3D computer models, my design focused brain can look at the plan, read the elelvations and get the 3D picture.
Which, given the straight segments is a somewhat complex bit of civil engineering.
But it will work just the way Tom drew it.
And I think in his situation it is a great idea rather than trapping trains in a hard to reach into helix, one of my objections to the helix idea now that I have decades of experiance with them on the various layouts of my friends.
I hope you scrolled up and found the track plan......
Greg,
Your conical helix is spot on. However, as Sheldon aleady mentioned, the open helix in my diagram will not be circular but elongated. Therefore, each rotation will NOT be 3" higher in elevation in the same spot as the level directly below it.
SeeYou190 I say "Working With", because I found out my room is 6 inches more narrow in one area than I was aware -Kevin
I say "Working With", because I found out my room is 6 inches more narrow in one area than I was aware
-Kevin
I thought that George on Seinfeld was the original individual who encountered “shrinkage”.
gregcall i tried to do was provide a a 3d image of what was being proposed
Thanks Greg, I get the helix part, now that I have looked thoroughly at Tom's plan, on page 1, along with Sheldon's "description" with the elevations, I understand the complete layout.
Tom, will be part of the 4x8? or a new layout? On your web site, I see have a plan for the "helix" part.
Mike.
My You Tube
This is an all new layout, Mike.
The dashed lines, is that more staging hidden behind a back drop?
Hi Tom:
I see your "strip mine design" with minimal scenery appears to comprise about half your room, and that the 2% grade permits about 4" rise per lap. In essence it appears to be a compressed nolix (with the operator in the center of the helix.)
In no way do I mean to be critical, but would you be better-off with a classic around-the-wall nolix, which would give you about 10-12" rise per lap and opportunities for vertical and horizontal separation, thereby allowing better scenery options? An additional benefit might be the ability to have the pass-through sections slimmed by having tracks at those places oriented above one-another, such that a swing gate could be devised (making laundry trips easier.)
Jim57
Mike,
The dashed lines in the left-to-bottom portion of the layout represent the upper mainline track @ +12" elevation. There is also a CW dashed line coming off one of the two +9" #6 turnouts on the right middle portion where the helix track ascends to and from the upper mainline. The dashed lines on the three left yards tracks disappear underneath the +9" portion of the deck where the helix track makes a reversing loop.
So, looking at it from the top, think of the layout essentially in four five parts or levels:
I'll try to post a diagram of the upper level mainline this coming week. That may help you (and anyone else who might be curious) see where it fits in, in conjunction to the levels below it.
And this is all just speculative planning at the moment, Mike. The layout that I actually build (Lord willing) may look nothing like what I've presented in this thread. It may not even include a helix. But...it's fun to exercise your mind and think what can be accomplished within the confines of the space that you have and make the most of it.
And I still have some studying of the prototype to do to make my protolance layout (based on the NYC) as plausible as possible. Always something to learn...
jim57In no way do I mean to be critical, but would you be better-off with a classic around-the-wall nolix, which would give you about 10-12" rise per lap and opportunities for vertical and horizontal separation, thereby allowing better scenery options? An additional benefit might be the ability to have the pass-through sections slimmed by having tracks at those places oriented above one-another, such that a swing gate could be devised (making laundry trips easier.) Jim57
Jim,
Thanks for sharing your thoughts and ideas and no offense taken to your suggestions.
Yes, I had considered the "nolix" (didn't know that was a word) option. As mentioned, I wanted to keep both the south (stairwell landing) and west (laundry room) lift-out accesses as simple as possible - i.e. tracks on one level or relatively on one level. However, complexity moved over to the helix portion in how best to contruct it and how to solve turning trains around - both on the mainline level and in the yard. With that design there is still definitely some refinement to be done.
That said, I'm seeing some real advantages to your proposed idea that I hadn't considered before but ones that I would like to incorporate that I woudn't have been able to with the open helix design - e.g. room for a small-to-medium sized roundhouse and engine terminal and a wye for turning passenger trains around.
Thanks!
Thanks Tom!
I'll be following along.
Tom, if you are open to other track plans, here are some ideas for your space. Hope you can follow along, I'm no good at making quick electronic drawings and posting them.
Roughly 10 x 18, correct?
I understand the two necessary doors.
I have no idea of your prototype goals...
But in that space I would go around the walls, no intrusion into the open center.
I'm not big on narrow shelves, I like scenery beyond the right of way, so I would do 18"-24" on the three sides.
The long wall on the right I would make the benchwork deeper, 36" would be good, leaving a 60" asile.
On that side I would put a staging yard across the back the whole length of the wall, which can be hidden under lift out scenery or behind a short backdrop.
By stealing some floorspace and making benchwork at top of your drawing deep, 60"?, similar to your helix plan, you could have a wye on the mainline and the leg off the mainline could wrap around an go to the staging.
This would have some great scenic potential as well.
Mainline could be double or single track around the room keeping the liftouts simple.
With only a little more complexity the mainline could go twice around the room with part of it hidden.
OR
Eliminaste the wye, and do a twice around running thru the hidden staging behind the scenery on the deep side.
Now for a novel idea. Want two decks with no helix or grade issues.
Build one of the layouts I have described above at about 54" above the floor. This would make the lift outs "duckable" during operations.
Then on the two walls not effected by the doorways, build as totally separate "Industrial Switching Layout" at about 34" and buy a nice office chair.
Mainline running up top, switching on the bottom.
Simple to build, easy to move if ever necessary, pretty decent mainline run, suitably long mainline trains with staging.
Pretty good outcome for 10 x 18.
Disclaimer - I have done a lot of track plans for other modelers, but I have no talent for designing track plans that simulate actual places. Because of our need for selective compression, the idea bores me - unless you have a warehouse and 3 million.
If any of these ideas interest you I would be happy to contact you directly and sketch up a few things.
Thanks, Sheldon! I will mull over your ideas and suggestions, as well, on a piece of graph paper to solidify what I am seeing in my own mind what you are describing.