Laying Flex Track on a Curve

[mike_lawyer]

I am using ME Code 55 flex track, and on one end of my layout with 22 inch radius curves, my engines have slippage.  I think there might be a slight unevenness in the trackwork.  Is there a good method for laying flex track on curves to eliminate uneven track work?  I have never had this problem before, but this is the first layout where I have used ME flex.

When forming the curves, I used sweep sticks from fast tracks to keep a constant radius.

[C855B]

Did you use transitions into the 22"R?

[Sumner]

....Is there a good method for laying flex track on curves to eliminate uneven track work?  I have never had this problem before, but this is the first layout where I have used ME flex....

It is easy with a simple tool you can print or make, use to be able to buy them but think that stopped a while back...

More info in the following link down the page a ways with ones you can also print for parallel tracks and links to the print files....

https://1fatgmc.com/RailRoad/Trackwork/Trackwork-Index.html

Sumner

[Curtis Kyger]

Here's how I achieve smooth problem free curves on my layout:

It starts with planning.  I draw the curves on paper or directly onto the plywood sub roadbed using a transom -- a yard stick with holes drilled at every inch mark; using a nail at the center of the curve in one hole; and a pencil through the hole providing the desired radius. I do include transition curves which --cast fear aside-- are actually very easy to do.  To bring that track center line to the top of the roadbed, I'm still using the split old trusty cork roadbed glued down to match the drawn track center line.

Then I glue the code 55 Atlas track along that line, soldering each and every rail joint [I know this may be blasphemy here on RW, but it works for me]. Take care at each and every rail joint; use the NMRA gauge to make sure you have perfect gauge after you've soldered the joints (and wherever you solder electrical feeder wires). Make sure the rail head lines up perfectly both vertically and horizontally as flanges on wheels love to find impact points.  That's pretty much it! 

Make sure rails are in gauge.
Eliminate all impact points.

If you've done that, most problems will be mechanical in nature (think car maintenance.).

Also... some people give the top surface of the cork a quick sanding before laying track: I do not, but I do look closely for crosslevel issues and resolve the extremely rare issues with styrene shims inserted between cork and the bottom of ties. Very minor issues can also be corrected when ballasting.

[jdcolombo]

Mike, when you say "unevenness" in the track work, do you mean VERTICAL unevenness or horizontal unnevenness (e.g., the curve "jiggles" out of smooth alignment). 

If you mean vertical unevenness, the best way to check for that is to use a flexible straightedge; I use one of my wife's sewing rulers, made from plastic but very precise, following the curve on top of the track centerline.  Gaps between the edge of the ruler and roadbed indicate potential problems.  Sand or shim as needed for perfectly flat roadbed before laying track.

To ensure horizontal smoothness, when I lay flex track I use PL400 adhesive (a 1/8" bead that I then flatten with a putty knife to a paper thin coat).  The PL400 remains flexible for about 5 minutes.  During that 5 minutes, I put my eye at track level and sight down the track from both ends along the curve to make sure there aren't any "wiggles" in the track.  Stiff flex track, like that from ME or Peco, can easily form a kink that can only be seen this way.  You have 5 minutes to eliminate kinks by pushing on the flex in the kinked area.

BTW, I use the "sight down the track" method to make sure that tangents are . . . tangent.  The yard tracks and tangents on my layout are perfectly straight this way.

John C.

[Ed Kapuscinski]

I'm a fan of my "tracksetta" gauge for ensuring straight track. So much so I just bought an even longer version.

As for getting curves right, I have what might be a somewhat unique approach. I use snap track at the appropriate radii as a guide. Take the track, flip it over, and Bob's your auntie.

Now, usually I worry more about "keep above a minimum radius" using Atlas flex (which is more flexy), but this approach should work for ME stuff too.

I have a set of 18" and 15" radius, again, mostly because in various plans those are the minimum radii I care about. Larger stuff is generally just figured out by connecting known points and letting the track do its own thing.

[mike_lawyer]

Mike, when you say "unevenness" in the track work, do you mean VERTICAL unevenness or horizontal unnevenness (e.g., the curve "jiggles" out of smooth alignment). 

If you mean vertical unevenness, the best way to check for that is to use a flexible straightedge; I use one of my wife's sewing rulers, made from plastic but very precise, following the curve on top of the track centerline.  Gaps between the edge of the ruler and roadbed indicate potential problems.  Sand or shim as needed for perfectly flat roadbed before laying track.

To ensure horizontal smoothness, when I lay flex track I use PL400 adhesive (a 1/8" bead that I then flatten with a putty knife to a paper thin coat).  The PL400 remains flexible for about 5 minutes.  During that 5 minutes, I put my eye at track level and sight down the track from both ends along the curve to make sure there aren't any "wiggles" in the track.  Stiff flex track, like that from ME or Peco, can easily form a kink that can only be seen this way.  You have 5 minutes to eliminate kinks by pushing on the flex in the kinked area.

BTW, I use the "sight down the track" method to make sure that tangents are . . . tangent.  The yard tracks and tangents on my layout are perfectly straight this way.

John C.

Hi John,

Thanks for all the insight, I was asking about vertical alignment.  I am pretty good at creating a nice radius with the track, so that is not really an issue.  It is more about preventing dips in trackage that could create wheel slippage for locos.

Mike

[peteski]

Hi John,

Thanks for all the insight, I was asking about vertical alignment.  I am pretty good at creating a nice radius with the track, so that is not really an issue.  It is more about preventing dips in trackage that could create wheel slippage for locos.

Mike

If the track is laid down glued/nailed  to a solid roadbed (like cork or bare plywood), there should  not be any vertical bumps.  If there are uneven spots,  then the roadbed surface would be to blame.

[robert3985]

I've been laying RailCraft and ME flex (Code70, Code55, Code40) track for decades and the "trick" to not having lumps, bumps and ski jumps (as with ANY flex track) is to sand your subroadbed, then lay your cork, then sand that.

Sanding both the subroadbed and the cork roadbed will get you a very flat surface, which is essential for laying your flex on.

For my cork roadbed (Midwest Cork Products N scale Roadbed), I use a simple 6" sanding block I've made from a scrap piece of premium pine 1X3 with 220 grit emery cloth attached to it, and sand the cork roadbed after it's been laid to my centerlines and the yellow carpenter's glue is dry.  I used a small, wooden linoleum roller to press the cork roadbed into the yellow carpenter's glue, which I spread with a fine adhesive spatula onto my sanded subroadbed.

I consider subroadbed flatness so essential, that when I construct my splined Masonite subroadbed from 1/8" and/or 1/4" tempered Masonite splines (in six foot lengths), I take them to my local cabinetry shop and have them planed so both top and bottom surfaces are flat. 

For grade transitions, I use my belt sander to make sure the transition is gradual and smooth.

For plywood I use for yards & industrial areas, I used sanded-one-side 1/2" and/or 3/4" plywood for the subroadbed.

Since my layout is portable, I also have sturdy, but lightweight benchwork done in 6' lengths, constructed from mainly premium pine dimensional lumber with 3/4" module ends for strength where the modules are fastened to each other.

So far, in the 30+ years I've been doing this, I haven't had any structural problems at all.

I also use thin CA to tack and glue my flex to my sanded cork roadbed, making sure I'm pressing downward firmly on the flex while applying the CA and Accelerator with a short, straight block of 1X3 pine so I don't glue my fingers to the flex rails.  This isn't permanent, but permanent enough to hold the track down until I paint, weather and ballast it...the ballast cement being the prime adhesive to keep it in place over the years.

I really like the stiffness of RailCraft/Micro Engineering flex because I can get it to exact radii.  I don't use any radius tools, but just lay it to a precise centerline, then use the M1-Eyeball method to make sure there are no kinks in it.  However, for straight track, I do use a thin metal ruler to make sure my straights are STRAIGHT...unless I'm laying branchline trackage and I want it to be wavy side to side a bit...like the prototype.

I also solder each and every rail joint, but I use 96/4 Tin/Silver, silver-bearing solder (not "silver solder") for all of my trackwork and Superior #30 Supersafe Soldering Flux because the solder is 5 to 6 times stronger than solder for electronics and electrical work.  This ensures that my joints are strong, stable, electrically conductive and because of the self-neutralizing flux, will last a long long time without corroding away.

Good luck!...and have fun!

Cheerio!
Bob Gilmore

[jagged ben]

@mike_lawyer

I don't generally think of engine wheel slippage as being a result of trackwork flaws.  I think of it as the result of underpowering a train.  The curve where you're have this issue...What is the grade on the curve and how many cars are you trying to pull with what type (brand and model) of locos, and how many?  Curves exacerbate underpowering because of increased friction on the wheel flanges.

[mike_lawyer]

It is zero grade trackwork, and I am running a Kato Mikado with a GHQ L-1 conversion hauling 32 cars.  These are stump pullers with the extra weight, but maybe on curves I am reaching maximum pulling power.

[bbussey]

I solder the sections of flex together before forming the curve. That eliminates kinks at the joints.

[NtheBasement]

I glue cork roadbed down with Elmers type glue and ME c55 on that with contact cement.  Uneven squeeze out of the glue can cause waviness.

I bought 20 2.5" pieces of 3/4 x 1.5 steel bar stock from a shop (charged $20 at the time) cut roughly with their bandsaw.  These have proved remarkably useful for all kinds of things.  When gluing I line those up along the cork and then the track to hold them down.  The result is very flat track.  I've seen others doing something similar with steel from various sources.  I've also seen people use pop cans laid on their side to clamp down the flex, but its not even on curves and doesn't weigh as much.  Soup can's don't work, they only touch the track at the ends.

If you lay a steel ruler on the rails and see any light coming from underneath you need to fix it.  Especially at turnouts.  Shimming dips with paper is probably your best bet - ballast hides it just fine. 

[mike_lawyer]

I have been using soup cans as weights to hold down the track, maybe that is causing some uneven track work?  I wasn't aware the can method can cause problems.  Previously I used push pins with Atlas C55 track.  I should try geting sone flat bars and see if that works better.

[Sumner]

I do a fair amount of roadbed prep,  looks like a lot but goes really fast and one ends up with a very flat uniform surface to lay track on.  Never going to get flat track without a flat roadved...

















Sumner