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Cutting sub-roadbed for L-Girder: do you have to "wing it" a bit?

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Cutting sub-roadbed for L-Girder: do you have to "wing it" a bit?
Posted by hominamad on Thursday, February 27, 2014 12:25 PM

I'm in the process of building my first layout. It's an expanded (5x9) version of the Virginian and I'm using L-girder instead of cookie cutter. My thought was that I could give myself a bit more room for error and have slightly wider curves using 5x9.

I spent a lot of time using AnyRail to adapt the plan to 5x9 and making sure I had nothing less that 22" radii and max 3% grades. After much tweaking I got everything to fit perfectly.

Now I'm up to the part of cutting the roadbed and finding that its hard to translate the plan exactly to get everything precisely right. If it was a 4x8, I would be able to trace the plan directly onto the wood, but since this is 5x9 I have to cut everything in non-contiguous pieces (I'm making sure that I don't have any roadbed splices under a turnout). Everything seems to be coming together at this point, but I'm worried that when I start laying the track, things won't fit exactly how they did on the CAD program. I spent so much time on the computer struggling to get everything to fit perfectly, and now I feel like I'm fudging it a bit for this phase.

So I'm wondering, when doing this process of the layout, do you have to sort of "wing it" to a degree? I guess one advantage of the L-Girder method is that if things don't fit exactly when I start laying the track, I can always cut a new strip of roadbed to correct it and just as needed - but I'm not even sure how to be sure that I'm laying the track exactly how I designed it in the CAD program.

Also, I think I may have made the roadbed a bit too wide. I used a 4" width for the single track climb going around, but I thought again that would give me more room to correct errors when I'm laying the track. I switched to 3" for most of the other pieces of single track.

Anyone have any advice to impart here? Two pics of my work : (I haven't attached any of the roadbed yet, just cutting the pieces first.)



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Posted by mlehman on Thursday, February 27, 2014 12:53 PM

You're doing OK. In fact, I was gonna suggest leaving things wider if at all possible. I did with my layout and it's paid off many times when I needed to move or add onto things.

You can always add on or make a new piece if you have something that needs more room. And if it doesn't, having wide shoulders helps with scenery, etc.

If this works for you, lay the inside or tightest radius track first. When you have it to a certain point like cut and laid (doesn't need to be wired or even spiked down), layout some test markings for the rest. Then you'll know for sure it all will fit.

Mike Lehman

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Posted by hominamad on Thursday, February 27, 2014 4:00 PM

Thanks for the response. Once I have all the pieces cut I was planning on attaching them all to the grid, and then tracing all of the switch locations. I was then going to lay the track (and cork) outwards from the switches.

Also I did think it would be better to have wider roadbed but it threw off my measurements a bit and was hard to get everything to fit in some places.

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Posted by mlehman on Thursday, February 27, 2014 4:06 PM

If in doubt, use your track components to stencil things out on the subroadbed. You'll quickly see if there are problem areas.

For your turnouts, if you'll have anything projecting underneath, make sure you don't locate the throw over a support that will make it hard or impossible to install a swicth machine, for instance.

Mike Lehman

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Posted by jrbernier on Thursday, February 27, 2014 4:37 PM

Looks Good!

  I see that you have 'L Girder' benchwork - Nothing 'wrong' there.  The other option is a box frame benchwork.  There is really nothing that cookie-cutter does not do.  If neede3d, just cut out more of it if you want just the sub-roadbed profile.

Jim

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Posted by bogp40 on Thursday, February 27, 2014 5:52 PM

Actually looks great so far. Looks like a decent 3/4" ply for the "sub roadbed" (you refered it to roadbed). The extra width is Ok, the only time you may want it narrowed, is areas of a steep elevation change adjacent to the track. The wide track platform can interfere w/ scenery/ landforms tto a lowered track. Any areas like this can be cut narrower  if needed. Wider sub roadbed helps that you are able to screw it to your risers outboard of the track allowing any changes to unscew from the riser.  The only suggestion, would be to add "radian" joists at a few spots to support the turns.  Although 3/4' ply is quite stong, don't overspan. Also whenever possible, try to cut the ply so that the outer graining is still following the track flow. you can cut up the a 45 degrees, but should avoid cross graining as the plywood is stongest when the graining parralels the cut strips (your pieces are wide enough that this won't be any issue).  By adding additional risers and don't span more than 16" you should be OK.

You have some fairly steep grades (3%). I haven't studied that track layout to see if that much is nec. Any place the ply sub roadbed will elevate into a grade or level out and decend, the plywood needs to be anchored to at least 2 risers and then bend/ flex the plywood up into the rise or flex back to level @ top of overeasing. This will allow a natural easment to be formed for those "upeasings" and "overeasings" Seaming the ply @ the top/ bottom of a grade will create a sharp/ abrupt "kink" that will need fiddling/ shimming with for roadbed and track laying.

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Posted by rrinker on Thursday, February 27, 2014 5:58 PM

 Wider is what you want - that gives you more room to 'fudge' so the track doesn;t run off the edge, vs trying to cut it perfectly precise. Also, it leaves some space for the scenery to attach to to fill int he open spaces. If you end up with a plce where it's a bit too wide, you can always lop off the excess with a saber saw. Much easier to lop off excess than to attempt to attach a filler piece where it's too narrow.

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Posted by doctorwayne on Friday, February 28, 2014 12:40 PM

hominamad
......and I'm using L-girder instead of cookie cutter......


I think L-girder refers only to the support system for the sub-roadbed, while cookie-cutter refers to the sub-roadbed itself - sheet plywood cut in some places to allow raising or lowering of those portions.

hominamad

My thought was that I could give myself a bit more room for error and have slightly wider curves using 5x9. I spent a lot of time using AnyRail to adapt the plan to 5x9 and making sure I had nothing less that 22" radii and max 3% grades. After much tweaking I got everything to fit perfectly. Now I'm up to the part of cutting the roadbed and finding that its hard to translate the plan exactly to get everything precisely right. If it was a 4x8, I would be able to trace the plan directly onto the wood, but since this is 5x9 I have to cut everything in non-contiguous pieces (I'm making sure that I don't have any roadbed splices under a turnout). 

The decision to go to 5'x9' for wider curves was a good one - too many people set a minimum radius too low in order to be able to cram more track into a small layout.  I believe that there is (or was) 5'x9' plywood available, although at a premium cost - with it, you could have simply traced your suitably-enlarged plan onto it and cut it out cookie-cutter style.

 

hominamad

Everything seems to be coming together at this point, but I'm worried that when I start laying the track, things won't fit exactly how they did on the CAD program. I spent so much time on the computer struggling to get everything to fit perfectly, and now I feel like I'm fudging it a bit for this phase. So I'm wondering, when doing this process of the layout, do you have to sort of "wing it" to a degree?


I'm in favour of "winging it", and more than "to a degree".  With flex track and the wide selection of turnouts available, you should be able to fill the requirements of your trackplan even if the actual track isn't exactly the same as the plan - an inch or two off, or a jog in the tracks here and there can make for a more interesting-looking layout, and it shouldn't have a negative effect on operations.

hominamad

I guess one advantage of the L-Girder method is that if things don't fit exactly when I start laying the track, I can always cut a new strip of roadbed to correct it and just as needed - but I'm not even sure how to be sure that I'm laying the track exactly how I designed it in the CAD program. Also, I think I may have made the roadbed a bit too wide. I used a 4" width for the single track climb going around, but I thought again that would give me more room to correct errors when I'm laying the track. I switched to 3" for most of the other pieces of single track. Anyone have any advice to impart here?

One of the supposed advantages of L-girder was the ability to move cross-members to facilitate turnout placement, so that the framing wouldn't compromise switch machine placement.  On a free-standing layout, though, open grid cross-members can be moved as needed, too.  Another advantage (a more valuable one in my opinion) is the ability to create a free-flowing edge to the layout.
I opted for open grid on my around-the-room style layout, and used cut-out plywood sub-roadbed, somewhat similar to what you're doing.  However, when I lost some layout room area to "family considerations" early in layout construction, I had to abandon my trackplan - it was actually more of a sketch - due to the odd shape of the room which I had remaining.  This is where "winging it" came into play.  I set my minimum mainline radius at 30", then cut up two sheets of 3/4" plywood into 2" wide curves.  The first sheet was cut, across the width of the sheet, in increasing radii - 28", 30", 32", etc.  The second sheet was cut mostly as 34" and 36", with a few larger ones.
After I had enough curved sections with which to work, I simply layed them atop the open grid framework wherever a curve was required.  As you can see in the accompanying photo showing the room's shape, that was just about everywhere.  

I chose the widest curves which would fit, and, when needed, cut more plywood to those sizes.  When all the curves had been roughed-in, I spliced the segments together, then connected them with straight sections of sub-roadbed.  Some of that was 3/4" plywood and some was good-quality 1"x4".  I've used only one switch machine (under a bridge on a wye - the only place where I had to use that 30" minimum radius), so the placement of the framing wasn't an issue and it shouldn't be for your L-girder framing either, as you can move any which is in the way - that is, of course, if you've attached the crossmembers with screws driven from below.  I have seen layouts where that wasn't done, and while the builder's plan may have taken the placement into consideration, it seemed unwise to discard that option.

Anyway, by all means feel free to "wing it" - this is, after all, a creative hobby, and that's a large part of the enjoyment which it offers.


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Posted by HObbyguy on Friday, February 28, 2014 11:01 PM

Glad you posted this- need to get down in the basement and do some more work on the sub-roadbed for phase 2 of my layout.  My job has had the railroad on the back-burner the past several weeks but its easing up a bit now, and your post is giving me some incentive.  Success with phase 1 adds to my confidence level but my phase 2 design is a bit more challenging... so some "winging" is needed.

Everything looks fine to me.  Some good advice has already been provided on using radial joists on the turns (especially under elevation changes) and joist spacing, roadbed width, etc.

Suggest that you take your time setting the risers and use levels and straight edge to make sure the grades are reasonably even between them.  I use a bunch of clamps when adjusting the risers and get them as close as I can before screwing them in place.  Just a little bit off can result in a hump or low spot.  Also make sure the risers are level side-to-side to keep your trains from leaning.  Putting some temporary track down directly on the ply and running some trains back and forth is also a good way to make sure everything is good as you go along.  If not satisfied then unscrew the riser(s) in that area, re-set the position a bit, and screw it back in.  Actually kind of fun.

 

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Posted by hominamad on Friday, February 28, 2014 11:33 PM

Here's some new pics of the progress from tonight. I actually finished cutting the majority of the pieces at this point - save for 3 or 4 straight sectoins which I'll fill in when needed.  I attached all the joists to their initial positions but I can already see it's going to take a lot of re-arranging.

A few more questions for you guys:

1) My benchwork is 5ft wide but only 8 feet long - and my layout exends almost to 10 feet long. So, this means I'm going to have around 10 in of overhang on either side of the benchwork. I can think of a variety of ways to support this but I'm not sure which would be best. The 3rd photo below shows one of the areas in questoin.

2) I would like to put a bridge somewhere, but I'm not sure where it will go yet. Do I need to decide this now? I don't even know what kind of bridge I want yet. Can I just lay track everywhere and then when I buy the bridge, cut the subroadbed and cork away from that sectoin and replace with a bridge?

3) When I splice the subroadbed together, I was planning on using scrap pieces of plywood, and attaching from the bottom with screws going up (don't want to use glue in case I need to move things around). Do the two joining pieces need to be absolutlely flush with each other like a puzzle piece? Or is it ok if there's a tiny gap which will be covered when the cork goes ion?

Thanks everyone for your help so far. I will keep posting pics of my progress here.

 

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Posted by alco_fan on Saturday, March 1, 2014 12:12 AM

hominamad
My benchwork is 5ft wide but only 8 feet long - and my layout exends almost to 10 feet long.

Is there a reason that you did not just build the benchwork 10 feet long in the first place?

Since you are where you are, I might slide the layout subroadbed to one side or the other so you that only have to build one outrigger rather than 2.

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Posted by HObbyguy on Saturday, March 1, 2014 12:37 AM

1) The real benefit of L-beam construction is that you can put the supports wherever they will do the most good and even move them later on if needed.  I would add another L-beam across the main frame maybe 18" or so in from the end and then add your supports radially something like this.  (With only a 10" extension you should not need any additional support underneath but I added some to tie the structure together since my extension was longer.)  This pic was taken around the same phase of the construction process that you are in, just before cutting out the subroadbed and adding the risers.

2) Yes you can add a bridge that way, as seen here.  The sub-roadbed was just set in place until the stream bed was formed, then I removed it, cut out the section for the little bridges and re-installed the sub-roadbed permanently.  I actually built the base/tie assembly for the trestle bridge on top of the sub-roadbed, then cut the sub-roadbed section out and added the trestle bents to fit the terrain.  Once all dressed out the supporting structure magically disappeared.

3) I drive the screws in for the splices from the top since it is easier to keep everything aligned and tight working from the top than working under the bench.  Once the roadbed and scenery is down the screw heads are well-hidden.  A tight joint is best, but I haven't worried about having a bit of a gap and haven't had any problems.

Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger...  doing it my way.  Now working on phase 3.      - Walt

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Posted by doctorwayne on Saturday, March 1, 2014 1:36 AM

HObbyguy
....Also make sure the risers are level side-to-side to keep your trains from leaning. Putting some temporary track down directly on the ply and running some trains back and forth is also a good way to make sure everything is good as you go along.....


Actually, if the sub-roadbed is on risers, it's easy to add superelevation, and I did so on almost all of my curves.  First, the risers should be clamped to the benchwork so that all to the subroadbed is at the height and/or grade desired.  Make a pencil mark on each riser which denotes the top edge of the joist to which it's clamped, then remove all of the clamps.  Select the riser closest to the mid-point of the curve, and elevate it until the pencil line is visible.  Now, push the bottom end of the riser towards the outside of the curve, and re-align the pencil mark with its joist - only the inside end of the line should touch the joist, while the rest of it will rise at an angle.  Clamp it in this new position.  I like to place a train on the curve before starting this operation, but you can do so after the initial adjustment if you're leery about trains toppling to the floor.  No track is required, as you only need to view the train to see if the amount of superelevation looks appropriate - unless you're running rocket-like speeds, this is merely for the visual effect.  Re-adjust as necessary, always aligning the inside end of the line with the top of its joist.  Once you've got the appearance you want, the other joists need to be raised in a similar manner - they're already offset due to the torsional forces applied through the plywood by the first riser, and that offset is diminishing as the distance from the centre riser increases - automatic easement into and out of the superelevation.  Be especially careful to only lift these risers while not forcing them further outward.

For vertical easements, the plywood (with the risers already attached to its underside) will form them automatically if you attach the risers to the joists in the proper order.  Determine the points which will be the top and bottom of the grade, and fasten those risers to their respective joists.  Next, find the mid-point of the grade and raise it to half the height of the entire grade.  If there's not a riser or joist at that point, span the joists on either side with a board or piece of plywood and add a temporary riser atop that.  Once thus raised, the plywood will form the vertical transitions at the top and bottom of the grade, and all you have to do is attach the risers to their respective joists at the point and height at which they are sitting.  Do not move them while fixing them in place.
I did my grades in this manner with the track already in place.  Since my grades are mostly on curves, this allowed me to easily measure the length of any curve or series of curves, simply by placing a train of known length on them.  For instance, the grade from my lower level to the proposed upper level is comprised of two horseshoe-type curves and a sweeping "S"-bend, with a couple of straight sections thrown in, and would be almost impossible to measure with a yardstick or tape measure.  Instead, I made up a 10' long train on a straight staging track and ran it up the entire grade, marking off the train lengths as it went.  The grade from bottom to top was about 45' long, and it was easy to determine the 22.5' point by again using the measured train.

Here's a more-or-less overall view, with one horseshoe curve at far left, another in the foreground, and the "S" curve in the distance at upper right:


...and as viewed from near the top of the grade.  I used a semi-radial arrangment of joists at the end of the peninsula and you can see the tilted risers supporting the roadbed and the vertical ones supporting the Masonite fascia.  Also note the overhang of the joists past the 2"x4" support structure and the 1"x1" cleats holding the open grid to it.  The overhang to the left of the picture is even greater, about 30":


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Posted by HObbyguy on Saturday, March 1, 2014 7:08 AM

Hominamad, hope Wayne and I haven't confused you.  He and I actually use very similar construction methods though it may not look like it at first glance.  We both have a pretty heavy base frame, and joists on top of the frame arranged more-or-less perpendicular to the track, and then risers supporting the sub-roadbed.  The main difference is that his frame is much lower and he uses very long risers, which allows him to have very dramatic below-track elevation changes.  I searched for a pic that shows my risers and could only dig up one.  You can see the risers on the side behind the temporary control panel.  My phase 3 will look a lot more like Wayne's since the main feature will be a large mountain ridge with big drop-offs, so much longer risers.  But first I have to finish phase 2 which goes off to the left in this photo Big Smile

You can see the curved fascia around the overhang at the end that I showed in my first photo, done just like Wayne's.  I like the flowing effect and it will give me a bit more room in what will be a narrow aisle compared to a squared-off end.

I wasn't going to get into super-elevation and did not put any into the track I have down now, preferring it to be just level, but Wayne covers that nicely.  As for grades, I never thought about using a train to measure the distances, so that one is a good tip for me too.

I think you will have to add some lumber to your frame to allow you to position your support joists at optimum positions and get them perpendicular to the track.  Should be easy to do this.  And then no problem running the joists out beyond the frame as needed at the ends.  Walt

Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger...  doing it my way.  Now working on phase 3.      - Walt

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Posted by doctorwayne on Saturday, March 1, 2014 1:27 PM

Nice-looking layout, Walt.  Yes   I like the way that the modelled portion segués into the backdrop, too.


Wayne

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Posted by HObbyguy on Saturday, March 1, 2014 1:49 PM

Coming from you Wayne I take that as a huge compliment!

Watching for the OP's update.  For some reason I have a real interest in this one.

Walt

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Posted by hominamad on Sunday, March 2, 2014 9:35 PM

Thanks for the great info everyone. I just placed the order for all of the track, cork, etc, so now I'm really at the point of no return!

Quick question for anyone who may know - or I was considering starting a separate thread for this:

I'm using all Peco track, flex, turnouts, etc. I'm a bit confused about what kind of switch machines I should get? There is something called the PL-10 which can mount underneath and looks like what I need. But some videos, sites I was reading were talking about a whole bunch of other parts as well - like an accessory switch, etc. I'm confused if I need to buy anything else as well to go with it. Also, even with the motors installed, can I throw the switches manually until I get it all wired up? I at least want to get the space for the motors cut out and the motors put in before I put the track down on top but am not quiet ready to power them yet. I decided to go with electrofrog if that makes any difference.

I'm surprised how little info there is online for this equipment.

Also, one more question - I'm going to just use rail joiners and spread out the connections over a few inches rather than solder for most places. But do you usually solder the first tracks leaving a turnout?

Thanks again!

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Posted by HObbyguy on Monday, March 3, 2014 9:07 AM

You probably should post the track questions as a new topic in order to get best feedback.  Please keep this thread running on the benchwork and sub-roadbed though!

Unfortunately I can't help much with Peco turnouts and switch machines.  But my understanding is that the points are sprung, so you should be able to lay them down and manually throw them for testing without any switch machines.  I personally wouldn't cut any holes until you have all the roadbed and track fitted so you know exactly where the switch machines need to go.  Also I have been soldering most all the track connections on curves but leave some joints un-soldered on straights and at all of the turnout connections.  And I am installing feeders as needed so as not to rely on unsoldered connections for power.  I imagine you will get some varied responses to this question.

 

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Posted by hominamad on Monday, March 17, 2014 10:08 AM

It's so hard to find time to work on this project, but finally got around to adding the 1 ft extension. Took the advice of someone here and just added 1ft to one of the sides instead of 6 in. on each side. Seeems very sturdy to me. I also added another cross brace to the table because it was starting to feel a bit wobbly.

I've laid out all of my sub roadbed on top and everything seems to fit nicely. I'm now ready to start splicing the pieces together and putting it up on the risers.

How do you guys recommend tackling this phase? I'm not sure if I should first splice two pieces together and then raise them up? Or first put all the risers in  and then attach everything? Or first splice everything together and then go around and attach to risers section by section?

The thing I'm most concerned about is that I don't want to end up in a situation where I did something wrong thats going to be a pain in the butt to fix later on. One thing I know to look out for is making sure I don't have any turnouts above a riser or splice. I'm also concerned about having tiny height changes that might make a bump under the tracks.

Here are a few pics of the latest situation:

 

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Posted by HObbyguy on Monday, March 17, 2014 4:29 PM

You are doing better than me.  I've got just about nothing accomplished the last month and I am in a similar place on my phase 2.  I almost went and bought a sheet of plywood over the weekend, but then it rained and I do all my cutting outside so no-go.

I clamp some risers in place, then lay the subroadbed on top and join the sections as I work out the grades and positioning.  I'll screw down the subroadbed in just a few spots to stabilize it and then play around with riser positions and heights until I am satisfied, then carefully screw everything in place.  I use a lot of clamps, and its not unusual to move the support joists, and cut and fit the same riser several times.  The beauty of wood is that it is easy to unscrew, reposition and screw it back in.Geeked

I think the extension is fine but a question in my mind is how you will manage the risers at the ends where the track runs parallel to the joists as it goes around the curves.  I have cross beams in the main structure so that joists can be positioned more-or-less perpendicular to the track even under the curves.  But granted there are a lot of ways to go about it.

Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger...  doing it my way.  Now working on phase 3.      - Walt

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Posted by Medina1128 on Tuesday, March 18, 2014 12:15 PM

I got lucky when I built mine. I found a company (now gone) that sold styrene templates. They had 3 or 4 different sets, depending on what your radii would be. They even had templates for turnouts!! 

One option you can consider is scanning the sections of track you will be using and printing them out full size. If you scan them into jpeg images, you can print out more when needed. I have some Peco turnouts on my layout, and you can download their templates from their website. I'm not sure about the others.

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Posted by HObbyguy on Sunday, March 23, 2014 1:45 PM

I finally got a bit of time to do some subroadbed "winging" on my phase 2, and posting pics of my progress this weekend.  Since you are also using L-girder and have a lot of questions Hominamad I figure it may give you some ideas, and others might find it interesting.  Don't know if the way I do it is the best way but it seems to work fine for me.

I do my design using XtrackCad, print it out full-scale and transfer the drawings to the ply before cutting out the sub-roadbed.  This area is quite tricky because it is so track heavy- and with elevation changes, a short tunnel, and two bridges just to add to the fun.  So a bit of a challenge.

Here's where I started after cutting out the subroadbed.  I positioned the joists in approximate locations, then set the subroadbed sections in place to check the fit.  Its not unusual for them to need a bit of trimming and fitting.  I am building one of the ME Viaducts for the straight elevated section at the rear and will remove the subroadbed and cut the section out for the bridge once I have all the risers set.

Next step is to begin adding risers.  I don't screw the joists in place until I am satisfied with the riser locations, and at first the risers are just clamped to the joists.  Once satisfied with a joist location then I screw it in place from the bottom through the "L".  I find that I move them around quite a bit until I am satisfied and Spax wood screws make it easy to reposition if needed.  Then I pull out the levels and adjust the risers to get the grades where I want them before screwing in the risers.  I don't connect the joints between subroadbed sections until everything is pretty close.  I really like the digital level, especially since it can be set to read in %grade.  When positioning the joists I also consider the facia.  It makes installing the facia a lot easier if the end of the joists are even and parallel to where the facia will be.

Here is a typical joint.  The new ply was a bit thicker than the older ply and I used a bar sander to smooth it out, then checked with a straight-edge to make sure there were no dips.

Like I said this area is a bit of a challenge.  The beauty of L-girder is that it is easy to position joists wherever they are needed since they screw in from the bottom.  The lower track goes through a short tunnel so it will need to be bullet-proof, though underneath access will allow for some maintenance.  I still have a lot of work to do to finalize the joists and risers in this area.

Foam cut to fit the foreground.  The land will drop off here a bit and I will carve the terrain into the foam.  Plaster shell is also an option for this and I mix and match methods, but find myself using a lot of foam just because it is easier to carve flat areas for structures "after the fact" and to plant trees.

It will take some thought how to form the terrain in this area to match the backdrop.  I designed my phase 1 with some ideas in mind, but made some adjustments to the terrain plan once I saw it all together.  Its a lot easier to "vision" once the sub-roadbed is in place.  I still have a few weekends of work to finish getting the subroadbed secured, then I will clean it up, take a step back and think about it for a bit.

Even though I traced the trackplan on the subroadbed sections before cutting it will still take some "winging" to get the track so it is free-flowing through the joints.  I will lay some temporary track down directly on the ply in the tighter areas using sticky-back tape for testing, just to be sure.  And I also use tracksetta gages to make sure tight curves are smooth and even when I glue the track down to the cork permanantly.  Broader curves are not so much a concern.

 

Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger...  doing it my way.  Now working on phase 3.      - Walt

For photos and more:  http://www.wkhobbies.com/model-railroad/

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Posted by hominamad on Tuesday, April 1, 2014 5:08 PM

Wanted to post some pics of my latest progress here. Things seem to be progressing well. I created the risers piece by piece and clamped each one in place. This took a bit of time. Then I went around and spliced together all of the sections. Now I'm going around the layout again, this time with a level, and screwing all of the subroadbed pieces to the risers - and then the risers with the girders. I hafve nothing to compare it to, but it seems to be good so up to this point.

For one of the sections, where I needed a riser and and track was going parallel with the braces, I cheated and put a crossing piece in place. Wasn't sure what else to do there.

A whole bunch more questions for you guys:

- Is there a way I could or should measure the grade of my climb to make sure it's ok? On the CAD program I kept it around 3-4%, but once actually raising it, I realized that it could be steeper in some parts and less in others. Not sure if this is something to be concerned with.

- On the same topic, when I lifted the climb portion, it created a natural inward bend - I guess this is something people try to achieve for realism? Should I try to level it out as much as I can or just leave it?

- I put a pic below of the area where my elevated section crosses over the track underneath. The space is around 4.25". When I put a train under it, as shown, it looks like I have way too much headroom. Should I leave this or can I lower it a bit? Lowering it of course would lessen my grade which would be a good thing.

- What is the best way to start laying down the cork? Should I first place all the switches where I want them to go and then draw lines out from there? Should I bother drawing lines at all, or should I Just start on one end and start tacking down the cork? I was planning on using tacks first before gluing anything so I can make adjustments.

- I still want to put a bridge somewhere but haven't decided where yet - and when I do decide, I'm not sure how to go about doing this. Once I lay all the track and have trains actually running, is it too late to cut out a section and replace with a bridge later on?

- Switch motors: I haven't bought any of these yet. Is this something I need to do while laying the track? I'm using all Peco electrofrog turnouts and I plan to mount the motors under the layout. From what I understand, you have to cut a sizeable hole in order to do this. I guess this is not something I want to do once all of the track is secured. I was hoping I could do everything - including wiring and running trains, and then add the motors later - but looks like not. I'm also not sure exactly what I should buy for the motors (or where to get them).

Thanks in advance for all the tips you guys are giving me.  It's been enormously helpful.

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Posted by fwright on Wednesday, April 2, 2014 4:44 PM

hominamad

- Is there a way I could or should measure the grade of my climb to make sure it's ok? On the CAD program I kept it around 3-4%, but once actually raising it, I realized that it could be steeper in some parts and less in others. Not sure if this is something to be concerned with.

One of the benefits of using cookie-cutter plywood roadbed is the natural grade transitions that are formed by bending the plywood.  As long as your plywood joints are not at the beginning or end of the grade, the highly desirable grade transitions will occur naturally.  Yes, the middle of the grade will be steeper than planned because the CAD program likely did not account for transitions in computing elevations.  With 3-4% grades, train length is going to be grade-limited.  But you will have many fewer issues if the middle portion of the grade creeps up to 4.5% to account for the space needed by the transitions than if you have abrupt changes to 3.5% grades.

- On the same topic, when I lifted the climb portion, it created a natural inward bend - I guess this is something people try to achieve for realism? Should I try to level it out as much as I can or just leave it?


You have discovered one of the generally unmentioned issues of cookie-cutter plywood.  The unwanted cross-wise natural tilt of the roadbed was pretty substantial on my 4x6 layout with 4% grades and 18" radius curves.  The easiest way to fix was to put in extra pairs of risers with cross bars between the risers.  This gave a level surface (the cross bar) to fasten the plywood to and forcefully remove the cross-wise tilt. 

- I put a pic below of the area where my elevated section crosses over the track underneath. The space is around 4.25". When I put a train under it, as shown, it looks like I have way too much headroom. Should I leave this or can I lower it a bit? Lowering it of course would lessen my grade which would be a good thing. 

The NMRA gauge in the vertical position on the lower track gives the minimum vertical clearance needed for all but modern (1970s onward) equipment.  Modern double-stack and bi-level passenger cars may be taller than the gauge.  The disadvantage of going as low as you can is that it can look quite awkward.  Only in tunnels does the prototype generally shoot for the minimum vertical clearance.  The advantage of staying close to the minimum is minimizing grades, as you mention.

- ...What is the best way to start laying down the cork?

I haven't used cork in a long time because it breaks down and crumbles over time.  Coating/sealing both sides with glue (ballasting and fastening cork) probably retards this process sufficiently in most climates.  I prefer Homasote, which also allows me to easily hand-lay track when I want to.

- Once I lay all the track and have trains actually running, is it too late to cut out a section and replace with a bridge later on?

My rule is that it is never too late to change things on a layout.  Model bridges have been done both ways - 1) built and laid with the track; 2) roadbed cut out and bridge built later on.

Unless you are building scenery at the same time as the track, approach #1 is difficult to match the scenery to the bridge after the fact.  Approach #2 requires extra care not to get vertical angles at the end of the bridge.  The roadbed needs to be fastened down at each end at the correct height before you cut it.  #2 also means you may be stopping operations while you cut out and build the bridge.

- Switch motors:  ...Is this something I need to do while laying the track? I'm using all Peco electrofrog turnouts and I plan to mount the motors under the layout. From what I understand, you have to cut a sizeable hole in order to do this. I guess this is not something I want to do once all of the track is secured. I was hoping I could do everything - including wiring and running trains, and then add the motors later - but looks like not. I'm also not sure exactly what I should buy for the motors...

If you use a simple lever from the motor to the turnout, yes, a fairly large hole is required.  You can drill the hole when laying the turnout and come back and add the motor later. 

An alternative is a linkage similar to ye olde Anderson link - a vertical tube with a wire inside that rotates with arms at top and bottom that connect to both the turnout and the switch machine.  This requires a much smaller hole, and is usually located off to the side of the turnout rather than under the turnout.  An offset linkage is much easier to install after the fact.

For Peco turnouts, you want to remove the latching spring when installing a switch motor (unless you use Peco motors).  Motors, hand throws, etc, are really your choice.  With the latching spring in place, Peco turnouts can even be thrown using your fingers.

my thoughts, your choices

Fred W

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Posted by farrellaa on Wednesday, April 2, 2014 9:12 PM

You seem to have a great start on your layout and are asking all the right questions.  I used the same type of construction for my layout except I had a lot of 3/8" (1/2" ply) plywood so I overlapped all joints and wound up with 3/4" total, but it made it easy to cut the thinner material. I glued each successive segment to the previous (with screws and/or clamps). The transitions were very smooth. I also made cardboard templates for all my subroadbed which I then traced onto the plywood. I happen to have a 14" bandsaw which made it very easy to cut the plywood. Just thought I would post this for others to consider (since you already have yours cut out) as an alternate way to make the cookie cutter components.

    -Bob

Life is what happens while you are making other plans!

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Posted by doctorwayne on Wednesday, April 2, 2014 10:19 PM

Fred has addressed your concerns quite nicely, so I'll only add a couple of comments.

hominamad

.....For one of the sections, where I needed a riser and and track was going parallel with the braces, I cheated and put a crossing piece in place. Wasn't sure what else to do there.

Hardly cheating, but merely taking advantage of one of the features of L-girder or open-grid construction.  Smile, Wink & Grin


hominamad

- Is there a way I could or should measure the grade of my climb to make sure it's ok? On the CAD program I kept it around 3-4%, but once actually raising it, I realized that it could be steeper in some parts and less in others. Not sure if this is something to be concerned with.

As mentioned, the naturally-formed vertical easements weren't considered by your CAD programme, but you can calculate the overall grade by measuring the length of the roadbed from the bottom of the grade to the top - it doesn't much matter whether you include the vertical easements or not, as long as you understand that they're a part of the grade over which you shouldn't exert any control - they're essential.  I outlined in my second post how to measure a grade's length by using a train of known length.  Simply divide the rise (4.25") by the length of the grade (expressed in inches), then multiply by 100. 

If you wish to keep the grade more-or-less constant, it's not that difficult to accomplish, but you first need to determine where the naturally formed vertical easements begin and end - they should not, for this purpose, be considered part of the constant portion of the grade.  Use the train-length method to determine the distance between the point where the lower vertical easement ends as the track begins to rise and the point where the upper easement back to level track begins, then mark the mid-point of that distance.  Install a riser either immediately beneath that point or as close to it as possible, then elevate the roadbed at the mid-point so that it is at exactly one-half the total height of the rise, then fasten that riser to the benchwork.  Depending on the length of the grade, the portions between this point and the upper and lower vertical easements may be sagging or simply require more support.  Again, determine the mid-points of both the upper and lower sections, and use suitably-placed risers to elevate them to 3/4 and 1/4 of the total rise, and continue to subdivide, elevate, and support the portions accordingly.  Do not add any supports under the naturally-formed vertical easements.


hominamad

- I put a pic below of the area where my elevated section crosses over the track underneath. The space is around 4.25". When I put a train under it, as shown, it looks like I have way too much headroom. Should I leave this or can I lower it a bit? Lowering it of course would lessen my grade which would be a good thing.

I'd lower it.  While I understand Fred's reasoning on clearance, you should consider what you plan on running - piggybacks, high cubes, etc. require more headroom than my '30s-era rolling stock. 
Because most of my layout involves fairly heavy grades in a somewhat sawtooth profile, I opted to squeeze the overhead clearances to keep the grades semi-realistic.  One locale is where the mainline crosses above a wye - the wye is crucial to operations but it allows only equipment less than 2.625" high.  This isn't a problem, as almost all of my rolling stock and all of my locomotives will easily clear.  The two exceptions include a large steam wreck crane with a tall stack, and gondolas loaded with automobile frames.  While the rules require the wreck crane to be moved with the boom trailing, it can easily be rotated to suit, and its boom idler car simply run around to the required position, so it never needs to be wyed.  The gondolas are in assigned service, and are not turned, as loading and unloading procedures (both off-layout) require that the car's orientation not vary. 
The other restriction is a tunnel - while the wreck crane is unrestricted through it, the gondolas' routing instructions restrict their movement to specific non-restrictive tracks - this is not an area through which they would normally pass, but it is also an area through which they are forbidden to move. 
I have a few cars with side clearance issues, too (mostly MoW equipment), and those restrictions are covered in the rulebook.  Imposing such limits can increase operational possibilities but you don't want to unnecessarily create problem areas which restrict your mainline operations, unless you have multiple lines to utilise.

 

hominamad

- What is the best way to start laying down the cork? Should I first place all the switches where I want them to go and then draw lines out from there? Should I bother drawing lines at all, or should I Just start on one end and start tacking down the cork? I was planning on using tacks first before gluing anything so I can make adjustments.

I used cork in most places and just started puttting it down anywhere - it eventually gets covered with ballast, so doesn't need to look too pretty.  In other areas, my track is directly atop the plywood.

hominamad

- I still want to put a bridge somewhere but haven't decided where yet - and when I do decide, I'm not sure how to go about doing this. Once I lay all the track and have trains actually running, is it too late to cut out a section and replace with a bridge later on?

 

I cut out the roadbed after it had been in service for some time, and used the cut-out portions as a form on which the bridges were constructed - this was necessary as almost all of my bridges are on curves.  However, I already had the basic landforms in place (plaster over window screen), and it was very difficult to build the bridge supports so that they conformed to the terrain.  It's also not especially realistic, as most real bridge building involves re-shaping the terrain to accommodate the bridge.  My suggestion is to build suitable benchwork to afford a flat location for any required bridge supports.  The bridge can then be installed at any time.

In the photo below, the foreground bridge supports were cast in plaster and were easily adapted to the flat riverbed and the sloping terrain to either side.  However, the individual footings for each leg of the support towers of the higher bridge to the rear are all at different levels. Bang Head


Here's another one with the same problem:




A better method would have been a flat platform atop the benchwork to support each tower at a suitable height relative to what would become the surrounding terrain. 
Some pre-planning is good, but don't let it get to the point where you become paralysed by fear of making a mistake.  Mistakes can be corrected, and they always provide a lesson. Smile, Wink & Grin


Wayne

 

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Posted by HObbyguy on Thursday, April 3, 2014 8:06 AM

You are definitely asking the right questions and getting great answers.  Just a couple of additional comments-

First off, there is no right way or wrong way to do things, as long as it works then it is "right".  You can add supports and braces wherever you want.  Just consider how they will impact plans for terrain and access for switch machines etc. as you go along.  Good that you are watching side-to-side level as well as grade.  The goal is to keep the trains level (unless purposely adding superelevation) and minimize twists that can cause all sorts of operational problems.

Using the heavy ply should help you with grade changes since vertical easements will occur naturally and be very stable.  But still take your time before tying everything down permanently to make sure there are no big dips that could cause de-coupling.  The grade does not have to be perfectly even but the steepest sections will likely be the limiting factor and define your maximum train length.  I found that anything over 3% can really start to impact length, depending on the loco, especially if on a sharp curve.  I am keeping the grades as small as possible (targeting 2% max) which will limit the height at my crossover more than I like, but it will reduce train length limitations.  You have a similar situation at your crossover and just have to decide what is most important to you.

Question- is your frame perfectly level?  My floor and celing aren't even close, so I use a builders level to try to get the frame perfectly level during construction, then use the digital level to double-check grades.  The grades we are talking about are very shallow so it is easy to get off if not careful.

So far I've cut the bridge sections out of the subroadbed before permanently mounting it and finalizing terrain, but it could be done later as long as the ends are well supported.  Consider bridge abutments and piers/supports as you go along with this.  I look at a lot of prototype photos to get an idea how they are done "real world".  Luckily there are a ton of variations depending on the era, type of bridge, and the designers/engineers that built the structure.  So you can pick and chose what fits and looks right to your eye.

Agree with Wayne that fitting bridge supports to existing terrain is a real pain, but it can give a very realistic effect, again depending on the type of bridge and era.

Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger...  doing it my way.  Now working on phase 3.      - Walt

For photos and more:  http://www.wkhobbies.com/model-railroad/

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Posted by hominamad on Thursday, April 3, 2014 8:35 AM

Thanks guys. I think I'm going to lower my crossover by an inch or so to lessen the grade. Also going to use the method Wayne described for measuring it. I guess it's hard to tell from the pics I posted, but does it look like the grade I have in place is ok? I will try to report back once I measure the exact amount.

Now the topic of the switch motors is bothering me. I did a bunch of research before and came to the conclusion that Peco switches were best, but now I'm reaing that many people don't like their switch motors. If I decide to use a Tortoise motor, then I know I need to take the springs out of the switches. But then I'm wondering if it was a good idea to buy the Peco switches in the first place? It seems to me that the behavior of the Tortoise motors are more realistic, and also require less wiring and perhaps are more dependable.

And Wayne - your bridges really look great!

 

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Posted by wickman on Friday, April 4, 2014 1:57 AM

A lot of good info in this topic.

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Posted by HObbyguy on Friday, April 4, 2014 6:14 AM

hominamad
I think I'm going to lower my crossover by an inch or so to lessen the grade.

I think that is a good decision.  I had big problems with excessive grades on my first layout many years ago.  This time I am being much more conservative, and tested grades with different locos before finalizing the plan.  Based on the testing that I did with my locos anything over 3% can be a problem with more than just a few cars.

Unless I missed it somewhere you haven't mentioned the era or type of equipment that you plan to run, and that makes a difference.  In general steam is more sensitive to grade and 3-4% would likely be a problem unless you are running articulated locos or double-heading.  Diesels are more forgiving, and if you run two or more in a consist then you can pull a bunch of cars up a pretty steep hill.

I've promoted laying down some temporary track directly on the ply to test grades and other tricky spots in the past (I use little bits of heavy double-sided carpet tape for this).  I think that its something that you should consider.  True that you might mess up some of the track doing this but it will answer critical questions.  Better to confirm that what you have is OK now, before tying it all down, than to find out you have problems after it is all together.

I am using Shinohara turnouts and Tortoises.  From what I understand the Peco turnouts are fine but not so sure I like the way the Peco switch motors are mounted.  Why not buy one of each (Peco switch and Tortoise) and test to see what you like?

Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger...  doing it my way.  Now working on phase 3.      - Walt

For photos and more:  http://www.wkhobbies.com/model-railroad/

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