Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

construction of constant radius spline?

4181 views
68 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    July 2009
  • From: lavale, md
  • 4,243 posts
construction of constant radius spline?
Posted by gregc on Friday, April 29, 2022 5:12 AM

i need a constant radius dia 56" loop at the end of a 32" wide pennisula.   i was planning on building the loop as a spline rather than using up a sheet of foam and dealing with supporting the outer edge.

planning on using 1/8" masonite, probably with softer and thicker material between layers of masonite.

wondering how to maintain a constant radius, assuming a curved wooden template cut at the inside radius for a portion of the circumference

doesn't need to be perfect if the spline is ~2" wide.   an accurate center line can be drawn when completed to locate the track

greg - Philadelphia & Reading / Reading

  • Member since
    November 2005
  • From: Phoenix, AZ
  • 689 posts
Posted by woodone on Friday, April 29, 2022 8:50 AM

Is the 56" the radius or the circumference ?

I guess that I would build a jig that might be just part of the curve.

Start the build and just move the jig has a section is completed.

Either way that is a big circle!

  • Member since
    March 2002
  • From: Milwaukee WI (Fox Point)
  • 11,254 posts
Posted by dknelson on Friday, April 29, 2022 10:43 AM

One of the nice features to spline roadbed is that it creates a natural easement curve.  But I do see the need to control things so that your desired minimum or "real" radius is maintained.  I think the idea of constructing it within a jig makes sense.  I assume that the finished spline roadbed will actually have some degree of flexibility when completed.

Dave Nelson

  • Member since
    January 2004
  • From: Canada, eh?
  • 13,149 posts
Posted by doctorwayne on Friday, April 29, 2022 11:11 AM

If you have a suitable surface on which to work, you could simply draw the curve in pencil, then use nails spaced-out along the line to act as a form, then add less-closely-space nails to keep each consecutive strip properly spaced from the previously-applied one.

Wayne

  • Member since
    July 2006
  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
  • 8,861 posts
Posted by BATMAN on Friday, April 29, 2022 11:54 AM

dknelson
I assume that the finished spline roadbed will actually have some degree of flexibility when completed.

Ya, it will be as flexible as cement.Smile, Wink & GrinLaugh

I put a nail where the centre spline was to go and proceeded to ad the three 1/4" splines to one side, then pulled out the nail and added the other four. Initially I just clamped the uprights to the grid as there was no set distance between them. Once the spline was in place I adjusted the uprights for height to adjust the grade by using a tailors measuring tape to measure the distance between them and doing the math.

 

I beveled the outside splines for that angled roadbed look, no need for cork roadbed on top if you do that, thus reducing the cost even more.

 

The curves in my spline were so far above the minimums that I did not need to worry about the radius, just the grade change. I just routed the spline as I went. The bench is 6' wide.

 

This 4' span without support has been there for 14 years and has not sagged so much as a mm. Someday a bridge will go in there.Laugh

 

I used 1/4" hardboard cut into 1" wide strips. Making them 1" wide makes the math easier when calculating grades. With no roadbed required this is very economical, you can get a whole lot of 1" strips out of a 4' x 8' sheet.

 

As far as mapping out the radius, when required, I use an old wooden yardstick with holes for the pencil tip at one end and a nail at the other. Close enough works for me.

 https://www.youtube.com/watch?v=KbUhA2_F-7M&ab_channel=BATTRAIN1 

 

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,240 posts
Posted by selector on Friday, April 29, 2022 12:58 PM

You can use the usual techniques: a trammel, pencil, on a surface.  

The idea of drawing the centerline through the arc you need, and then using dowels or nails driven into the surface at the appropriate distance from that depicted arc that would allow you to form the arc out of splines with the nails/dowels acting as fulcrums should work.

MDF splines worked well for me formed around screws driven into the tops of risers. If you're not fixated on precision here, and are satisfied with an approximation of a specific radius, that's the way to go.  Glue an initial three splines on the outside of the screws, lapped and clamped, and when they're solid, another three lapped and clamped to the first splines, but on the inside of them along the curve.  

And Brent knows from experience that splines are like concrete.  No sproing, unless they come unglued, no give, not in any axis.  They're like 3" steel pipe 18" long.  Good luck bending it without significant mechanical help.

  • Member since
    June 2007
  • 8,763 posts
Posted by riogrande5761 on Tuesday, May 3, 2022 11:41 AM

I've wondered, why spline?  It seems like a lot more work.

Rio Grande.  The Action Road  - Focus 1977-1983

  • Member since
    July 2006
  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
  • 8,861 posts
Posted by BATMAN on Tuesday, May 3, 2022 1:35 PM

riogrande5761

I've wondered, why spline?  It seems like a lot more work.

 

I love spline as it was so much fun to lay/install?  It was over way too fast for my liking. You can get 64 linear feet of subroadbed for the cost of a sheet of hardboard, so if you are on a budget you can't beat it. There is not the waste you get with cookie cutter. You do need a saw to cut it up though. I have a table saw and a radial arm saw. I wheeled the radial arm saw outside and used that. I cut the sheets in half lengthwise with the circular saw and fed them through the radial. Don't forget to bevel/taper some of the cuts for the outside pieces.

I used a combination of spline and foam for subroadbed. Next time I will put spline everywhere under the mainline as it is more solid and stands up a little better under the mains. Don't get me wrong, if you want to lay your track on foam go for it, I have had no issues doing just that. The spline just gives that little edge over foam for a subroadbed.

I have added turnouts and sidings in a couple of spots and all it took was to glue some more splines onto the existing ones which took no time at all to do.

For terrain, you can butt foam up against the spline, staple or glue screen, or cardboard strips to the side of it. Choose your favourite method.

Here I had a change of plan in the terrain and glued cardboard to the side of the splines with the glue gun. The double track is splines with spacers in between.

  

Depending on what tools you have, there is more than one way to build a layout.

 

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

  • Member since
    July 2009
  • From: lavale, md
  • 4,243 posts
Posted by gregc on Tuesday, May 3, 2022 3:54 PM

riogrande5761
I've wondered, why spline?  It seems like a lot more work.

less material and hopefully stronger structure in a more exposed location

greg - Philadelphia & Reading / Reading

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,240 posts
Posted by selector on Tuesday, May 3, 2022 5:24 PM

riogrande5761

I've wondered, why spline?  It seems like a lot more work.

 

It does seem like a lot more work, and that was my orientation when I did it on my second layout.  I was surprised, though, at how quickly it went.  The thing we all seem to miss is that, if you slat up a sheet of 1/4" MDF, a full 4X8 sheet of it, you'll end up with about forty-five 8' long slats.  It might take you a couple of days or four to layeer four or more splines for your main, waiting for the glue to dry each time, but inside of three/four days you have 50' feet of nicely flowing roadbed.  The splines naturally curve in any axis as you lay them, provided you take care to position your supporting risers correctly to help orient them according to your plan.

Once I closed my loop, I think inside of three days for the layout pictured below, by far the heaviest workload was forming the terrain over sheets of window screen by mixing and dying successive, many, many, successive 8 cup batches of 'ground goop' using that formula that Joe Fugate shared with us here back in 2004/5.  But the mains, fashioned from 5-6 layers of 1/4" X 15/16"X 8' splines went at a torrid pace due to their 8' lengths.

Again, once they're dried, they're amazingly robust and rigid.  At that point, the limit to their durability lies in the strengths of the various supporing risers and how they're anchored (normally, top predrilled down into the top of the riser, countersunk enough to bury the head of a simple 1.5" wood screw).

  • Member since
    July 2006
  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
  • 8,861 posts
Posted by BATMAN on Tuesday, May 3, 2022 6:02 PM

selector
It might take you a couple of days or four to layeer four or more splines for your main, waiting for the glue to dry each time,

Crandell, what glue did you use, just curious? I used a hot glue gun, I would glue and clamp about three or four feet at a time and of course, it was set in under a minute and I moved on. After it was all together I used drywall screws every foot alternating sides. It is very important to drill pilot holes for this. I also used drywall screws down through the top into the riser.

It has been in place 14 years without showing any sign of failure.

I also put a little superelevation in by using a rasp. That was very easy.

  

Went to a steel stud and cement roadbed over the fireplace to avoid expansion and contraction issues. 

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

  • Member since
    January 2009
  • From: Maryland
  • 12,169 posts
Posted by ATLANTIC CENTRAL on Tuesday, May 3, 2022 9:26 PM

I have been watching this with some interest. I have built a lot of layouts, both for myself and for/with others.

I have never used spline roadbed.

On the other hand, I have never used foam either.......

I get the idea of the free flowing more natural path, I just never saw an easy way to establish that path?

My other built in bias - I don't like Masonite.

Other concerns/questions - underside clearance, roadbed thickness for switch machine rods, clearance for hidden trackage below?

AND, a great many of my layouts have had lots of double track - or more - that's a wide spline.....

I'm with Jim at this point, it seems like a lot more work?

AND, I always viewed it as something for layouts with very large radius curves, potentially larger than my 36" to 48" curves.

Surely not for 28" radius curves? But what do I know? Not much about this method of construction.

For what it might be worth, I have seldom cut large curved sections out of plywood either, there are strenght issues with that. 

I have used a biscuit joiner to join sections of roadbed cut from 3/4" lumber. I have laminated 3/8" plywood into 3/4" "seamless" curved roadbed.

While the detailed civil engineering of my trackwork is done during construction, I do often desire or need to follow the "plans" pretty close to make everything work, track centers, easements, etc.

Thoughts please.

Sheldon

    

  • Member since
    July 2006
  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
  • 8,861 posts
Posted by BATMAN on Tuesday, May 3, 2022 11:03 PM

ATLANTIC CENTRAL
Thoughts please.

I agree that masonite is a weird product and I am not even sure why it is made. I have used it for the spline roadbed and my backdrop and have not had the slightest issue with either one, however, I can't think of anything else I would ever use it for.

When I went with foam and spline it was just to try something different. I am not in the same league as most on this forum, for every hour I spend at the hockey rink with minor hockey and other community activities I spend seconds on the layout. After fifteen years my photos show not much progress.

I have not had any issues with using foam or spline. I am just getting to the point of installing switch machines and I am using Rapido switch machines that are installed topside. Rapido has an installation video that shows how to install them in foam or wood. 

My layout is pretty simple and straightforward,  built for running trains and modeling the vastness of the landscape found through the Rocky mountains. There is a very good chance there is another layout in my future when we move. I have been exposed to all types of layout construction since I was a small boy. I am convinced there is not a one size fits all for that. I would bet I will use a combination of all types of construction on the next one. Any mainline will be on spline and/or plywood, yards will be on ply or foam. I will certainly use foam for terrain as it is so versatile.

People generally do not like change and the rhetoric and reasons for not doing something different always jump to the forefront without any consideration that there might be benefits to making that change.

Way back when I joined this forum there were some pretty intense conversations about how people were moving away from L-Girder construction that I frankly could not get my head around. In all aspects of life change is growth, sometimes it is for the better sometimes not so much.

I see no reason to defend using spline or foam or L-girder or cookie cutter or anything else. Use what you are comfortable using, for me I have now tried foam and spline and they are firmly implanted into my arsenal of layout building methods.

 

 

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,240 posts
Posted by selector on Tuesday, May 3, 2022 11:23 PM

I fear we might be hijacking this thread.  Although, it's partly relevant.  Sorry to Greg if we are doing so.

My first layout was mostly foam.  It worked, but as you might imagine, me being wholy green, it was not a great effort or result.  Next, I thought I'd give splines a try, and I think it went swimmingly.  Third was cookie-cutter and I made a large helix with a mountain cover.  Again, success.

So, like Brent, I like to try different things.  The splines are no more spendy on time than any other method I have tried, and I'm going on three different methods now.  Fashioning vertical and horizontal easements are a breeze with splines.  If you situate your risers at the appropriate heights, they'll bend naturally, just like flex track.  Probably the trickiest part is walking away only after you're sure the splines are all lined up against each other when you clamp them. Otherwise, you have a lot of shaping to do later with the surform file.

Brent, I used aliphatic resin, or yellow glue.  I only used the hot glue to affix the window screening swatches to the sides of the splines.  I don't know that I trusted the hot glue with the splines, and maybe, I forget now, the instructions I followed said to use wood glue.  It was somewhat messy, as you would assume when clamping the splines, but paper towels or newsprint took care of that problem.

  • Member since
    January 2009
  • From: Maryland
  • 12,169 posts
Posted by ATLANTIC CENTRAL on Tuesday, May 3, 2022 11:29 PM

Brent,

Thanks for your thoughts.

I'm an engineering kind of guy, so show me way something is better and I am all in. One example for me was gluing down track with adhesive caulk.

BUT, I don't imbrace change for change sake, new is not always better, often it is just different.

I'm already heavily invested in Tortise machines, Atlas switches and track, and a few other things.

Nothing has come along to justify replacing those investments, at least not as it relates to my specific goals.

But back to benchwork. I have always built some sort of hybrid open grid/L girder benchwork combined with table top for areas like cities and yards.

One of the first questions I have with spline is how to transition to table top areas?

For my purposes these days, I see L girder as pointless - it is for people who plan as they go and who are likely to make changes - neither applies to me.

Spline seems hard to plot the exact curve or location, that is the part I don't get?

Thanks again,

Sheldon

    

  • Member since
    July 2009
  • From: lavale, md
  • 4,243 posts
Posted by gregc on Wednesday, May 4, 2022 6:06 AM

ATLANTIC CENTRAL
I'm with Jim at this point, it seems like a lot more work?

ATLANTIC CENTRAL
show me way something is better and I am all in.

???

greg - Philadelphia & Reading / Reading

  • Member since
    September 2004
  • From: Dearborn Station
  • 23,318 posts
Posted by richhotrain on Wednesday, May 4, 2022 6:12 AM

gregc
 
ATLANTIC CENTRAL
I'm with Jim at this point, it seems like a lot more work? 
ATLANTIC CENTRAL
show me way something is better and I am all in. 

??? 

Read on! The rest of Sheldon's post explains these remarks.

Rich

Alton Junction

  • Member since
    July 2009
  • From: lavale, md
  • 4,243 posts
Posted by gregc on Wednesday, May 4, 2022 7:46 AM

sorry.   i didn't see the better any other approach being suggested

greg - Philadelphia & Reading / Reading

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,240 posts
Posted by selector on Wednesday, May 4, 2022 8:31 AM

Sheldon - " ...But back to benchwork. I have always built some sort of hybrid open grid/L girder benchwork combined with table top for areas like cities and yards..."

Sheldon, you asked how to transition splines to level surfaces, like to a yard throat or something similar where the expanse opens for ladders, caboose tracks, etc.  It's the same philosophy as you state in my quote of your text.  You figure it out, you engineer it, you nip 'n tuck, cut out, shim up, that sort of thing.  You bring the splines down to level by fashioning them to meet, at grade, with the yard surface.  That could be with a shorter riser to accommodate the spline's vertical depth, or notch a joist....whatever seems to work and will bear weight sufficiently.

  • Member since
    December 2008
  • From: Heart of Georgia
  • 5,133 posts
Posted by Doughless on Wednesday, May 4, 2022 8:33 AM

I have never used Masonite as spline, but I have spanned a 6 foot distance by laminating three 1x4s together with glue and screws, then capping it with a traditional board, in my case a 1x6 for an extremely narrow shelf over the span.

If I wanted a wider subroadbed table top, I could use two 1x4 lam-beams spread 16 inches apart. 

I could see using the masonite for making curves, as a support for traditional plywood subroadbed.  Cut out plywood at the precise curve, then use it as a template for the masonite spline, and as a final cap so traditional caulking or nailing roadbed and track to plywood would still happen.

- Douglas

  • Member since
    July 2006
  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
  • 8,861 posts
Posted by BATMAN on Wednesday, May 4, 2022 10:36 AM

ATLANTIC CENTRAL
I don't imbrace change for change sake, new is not always better, often it is just different.

I agree and I am always trying new things that come along, and sometimes they are not for me and sometimes I go wow! Until you give them a try you just can't tell by looking at them. Guitar strings and my new hybrid Toyota come to mind.

ATLANTIC CENTRAL
I'm already heavily invested in Tortise machines, Atlas switches and track, and a few other things.

That would be more than enough reason to go with a subroadbed that easily facilitates the use of these things, I would likely do the same. I have not made that investment yet and Rapidos switch machines I like for two reasons, one, the switch stands, two they are installed topside which means fit as I am, there is no crawling around under the layout.

ATLANTIC CENTRAL
But back to benchwork. I have always built some sort of hybrid open grid/L girder benchwork combined with table top for areas like cities and yards. One of the first questions I have with spline is how to transition to table top areas?

Hybrid is the keyword and right there you are admitting you are open to change. Where I have spline on my layout it is a 70' single track run with no turnouts. If I was to have more than one track with or without turnouts I would have started reassessing what to use. I think one sheet of masonite was $8.00 when I built my spline and I got just about the whole 70' of roadbed out of that, What is the cost of 70" of roadbed done with ply? For you and I, the difference doesn't really matter but to some it does.

ATLANTIC CENTRAL
One of the first questions I have with spline is how to transition to table top areas?

You are a high-caliber craftsman with a lot of tools, so as Crandell suggested, sometimes you need to be creative which is all part of the fun in my book.

ATLANTIC CENTRAL
For my purposes these days, I see L girder as pointless - it is for people who plan as they go and who are likely to make changes - neither applies to me.

Fifteen years ago on this and other forums, I got really lambasted by a small few when showing my open grid benchwork. It seemed L-Girder was the only acceptable method for the true modeler. Thankfully that has changed.

ATLANTIC CENTRAL
Spline seems hard to plot the exact curve or location, that is the part I don't get?

 

I made these curve gauges out of heavy cardboard from appliance boxes, I just used them to make sure I made the minimum radius but was not rigid with where the supports went as I had lots of room. I layed them on top of the grid and marked with pencil where the supports would go and clamped the supports in place. The spline just flowed naturally and perfectly from support to support. After the spline was in place I made tiny height adjustments where nessassary and screwed them in.

I now have a grade/slope app on my phone that is so cool, wish I had it back then. I push my phone around the track and it gives me the exact slope. Beats the old method of measuring slope.

The best part of spline was I found it so much fun to do. I used a hot glue gun and it went up really fast. I think if I used wood glue like Crandell did and had to wait for it to dry I would have used the cookie-cutter method.Laugh

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

  • Member since
    June 2007
  • 8,763 posts
Posted by riogrande5761 on Wednesday, May 4, 2022 10:56 AM

Thanks for explaining.  Maybe spline to me would be teaching an old dog new tricks.  Also, I too wonder how you can control the radius - you can't really draw a precise radius with a trammel for example.  As for smooth flowing, I believe I can get smooth flowing with conventional methods too and have.  To me at best, it seems 50/50 spline vs. conventional.  It seems "exotic" and perhaps something cool builders do but maybe I'm turning into a curmugeon!

Rio Grande.  The Action Road  - Focus 1977-1983

  • Member since
    July 2006
  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
  • 8,861 posts
Posted by BATMAN on Wednesday, May 4, 2022 11:05 AM

riogrande5761
Also, I too wonder how you can control the radius

I don't believe in a stamped-out set radius for the whole curve, a lot of my curves have a changing radius as that is what you see in the wild as the track follows the landscape. As long as the minimums are met the visuals look much better with a flowing curve that opens up as it goes around. 

Of course, this really depends on how much real estate one has to play with.

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

  • Member since
    July 2006
  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
  • 8,861 posts
Posted by BATMAN on Wednesday, May 4, 2022 11:43 AM

I see we didn't really address your queries.

gregc
planning on using 1/8" masonite, probably with softer and thicker material between layers of masonite.

I would use 1/4" masonite, seven splines are what I used, you add another if desired.

gregc
wondering how to maintain a constant radius, assuming a curved wooden template cut at the inside radius for a portion of the circumference

Once you have a single spline done overlapping three or four feet you will be able to adjust the curve to your template. The minute you add the second layer of spline it ain't adjusting. It is easier to do than it sounds.

gregc
doesn't need to be perfect if the spline is ~2" wide.   an accurate center line can be drawn when completed to locate the track

 

With seven 1/4" splines the track fit perfectly, in this pic I drew a line on the centre spline just so I knew which one was the centre while I was attaching the others.

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

  • Member since
    January 2009
  • From: Maryland
  • 12,169 posts
Posted by ATLANTIC CENTRAL on Thursday, May 5, 2022 4:08 PM

So I watched a couple Youtube videos about spline roadbed...... Disclaimer - I can hardly ever make it thru a model railroad how to video.....

Not everybody was using Masonite.....

I would still like to hear from anyone how they fiquire out where to put the risers in advance andhow you attach the first (on any) piece of the spline to the riser?

Sheldon

    

  • Member since
    July 2006
  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
  • 8,861 posts
Posted by BATMAN on Thursday, May 5, 2022 7:07 PM

As far as figuring out where to put the risers I just marked the top of the grid and put the risers along the way. I did lay my big cardboard curve (radius checker) cutouts on the grid to double-check I had the curves right and as I was setting the first spline I also checked again.  As the risers were not all the same distance apart the height of each riser had to be calculated individually. If you were to lay the spline right on the grid there would be no riser as it would be attached right to the grid.

In this photo, you can see a nail, this is where the center spline goes. I used a spring clamp to hold the single spline to the nail. Once the placement was good I laminated the second spline (staggered overlap) and once that was done it was not moving. So once you have three splines on one side of the nail, you pull the nail and add the center spline where the nail was, and then the other three for seven 1/4" splines. The two outside ones were tapered. I could lift the splines up and put a dab of glue on the top of the riser and then drilled a hole and put a drywall screw countersunk through the spline down into the riser. I also drilled holes every foot alternating sides and put drywall screws in there as well. It all went very quickly.

I tapered the outside splines with the saw, however, some people do it with a rasp, I have not tried that.

Sheldon, for the cost of a sheet of masonite, you could give it a try and chuck it if it is not up to snuff. You have a lot of ground to cover with your new layout. Using spline for just some of it could save you some serious $.

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

  • Member since
    January 2009
  • From: Maryland
  • 12,169 posts
Posted by ATLANTIC CENTRAL on Thursday, May 5, 2022 7:32 PM

Brent, trust me, I have not rulled it out by any means. 

Another concern/question is the fact most of the mainline trackage on the layout is double track, requiring a 4-5 inch wide subroadbed?

That's a lot of 1/4" thick pieces of anything....

One guy on Youtube was using strips of wood that milled on a table saw, they appeared to be more that 1/4" thick. Not sure how sharp of a radius he was building, is sample shots were very gentle curves.

Sheldon

    

  • Member since
    July 2006
  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
  • 8,861 posts
Posted by BATMAN on Thursday, May 5, 2022 8:27 PM

ATLANTIC CENTRAL

Brent, trust me, I have not rulled it out by any means. 

Another concern/question is the fact most of the mainline trackage on the layout is double track, requiring a 4-5 inch wide subroadbed?

That's a lot of 1/4" thick pieces of anything....

One guy on Youtube was using strips of wood that milled on a table saw, they appeared to be more that 1/4" thick. Not sure how sharp of a radius he was building, is sample shots were very gentle curves.

Sheldon

 

I have a stretch of double track and I used 2 x 7 strips with blocks between and I put a strip flat on the blocks between the two for the ground cover. 

I watched and read a lot about it before I took the plunge and went with the masonite, however with your expertise in materials you may find a better choice.

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 

You can never ever out-train poor nutrition.

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,240 posts
Posted by selector on Friday, May 6, 2022 2:02 AM

I 'draw' my layout's tracks by using masking tape applied to the rug or the flooring. Contrary to riogrande's assertion, you CAN make a precise curve using a trammel.  All you need is a fixed anchor/pivot point, something like a heavy piece of wood, a slab of rock or drywall, anything that has a small hole in it into which you insert the pivot point (a screw typically). 

I use the tape and a plumb bob to place the risers.  As Wayne and I have described many times, you clamp the risers, or screw them if you must, and then adjust them when you're getting close to fixing your grade and curve.  The glue must not have set, and you must be able to let the splines adjust a bit, even sliding against each other a bit, as you tilt the risers to fashion super, as an example. Once you eyeball the set of the splines, their curvature and gauge loading clearances, and their rise and fall on grades, you can finalize the risers by screwing them into place.  That's how Wayne does it, if I understand him, and it's how I did it...the fixing part, tilting the risers to allow super-elevation.

If you're more concerned with spacing and placement, and not tilting them, just use your engineering spidey sense about how often you'll want a riser to hold the splines, or if you'll need one at the apex of a curve (because you need to drive a screw into the top of the riser and use the screw as a fulcrum around which you bend the splines into the curve radius you want.).  Just as you pretty much guess, intuitively, how often and where to place risers for cookie-cutter end abutments so that they stay and meet at grade across the joints, you do the same for the spline risers.  Where you need a riser, you measure, cut, and affix a joist, even at odd angles.  It's the way I did it, and it worked really well.

I think my risers were spaced on average about 3' apart. Mostly that was for curves, not for support.  Them things are plenty strong when you have four or more of them glued together. For cookie cutter, I use about 14".

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,240 posts
Posted by selector on Friday, May 6, 2022 2:18 AM

Here is an early photo of my splines.  It seems my riser spacing wasn't as far between as I recalled.  It's more like 2', probably due to my desire to fashion curves.

Note the double track spline at left, inside, in the distance, with the wood spacer between the splines.  That was the siding, the only place where I built twinned and parallel splines for any distance.  

This was 9' X 13':

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!