Getting flex track perfectly straight?

[stottman]

Does anyone have any tips, or "Lessons learned" to get flex track perfectly straight?

Tried various methods. "Fast tracks" straight inserts, MLR flex track tool, and 3 and 4 foot sight edges...While it comes out reasonably straight, its not perfect.

I am using Midwest cork, with Peco code 83 that is caulked down. Using a centerline doesn't work , as the midwest cork is not perfect either. 

Thanks in advance!

[riogrande]

I draw a perfectly straight centerline using a nice true piece of dimensional lumber such as an 8' long 1x3 and then lay the flex on that centerline.



Some may used the metal templates but I prefer laying track on the centerline and check by eyeing down the track.

[fr8kar]

I made several 3D printed tools at Shapeways years ago to set a specific radius in Micro Engineering flex track. I also made some to straighten the track. You put it between the rails and use the handle to slide it back and forth. They work very good but no method will result in perfectly curved or perfectly straight track, not without a little dialing in by hand and eye.

www.shapeways.com/shops/he6agon?section=Tracklaying+Tools&s=0

www.shapeways.com/product/VCGE2N379/me83-tangent?optionId=57564918&li=shops

[riogrande]

Yes, tools or techniques gets you most of the way there, but nothing replaces the eyeball.

[ambluco]

There is a "U" shaped piece of aluminum you can purchase at Home Depot or Lowes. It fits exactly between the rails and gives perfect results. You can also line it up agains the ties if you want to do it that way.

[edwardsutorik]

It helps to start with straight track. Years ago, I learned a method where you held one end of the track and kind of "whapped" it on a flat table. The track is held with the ties vertical, and you might flip it over. It worked for me, it might work for you. Shouldn't hurt to try. I didn't believe it would work until I saw that it did.

Since you're doing straight track on flex, it does seem drawing a nice center line is a good START. You'll probably want some straightedges of different lengths. Most anything you choose will be wider than the top half of the roadbed it's sitting on, so it will want to fall off. Also you'll need 3+ hands. A way around these problems is to use an assortment of (straight-ish) yardsticks ('cause they're cheap) and cut them to handy lengths. Then drill a hole in each end so you can gently drive a small nail through each hole. Get one end in position and nail it--not too much, just to hold it nicely. Then swing the other end into position and nail it, too. Run you marker down the side, and you have your straight line to follow.

I suppose you could also use these straightedges to mark one end of the tie placement. Easier to line up to, plus the straightedge will have more support.

I use spikes into the cork to secure (that should be in quotes) the track. What's good about the spikes is you can reposition things. You might go with temporary track nails. Anyway, sight down your newly installed track. Maybe use a small mirror to help out. Fix all the problems you see. If you don't see any more, you theoretically are done. You probably, however, should quit for the day; and recheck it tomorrow. The spikes may not hold well enough for you, so you could put some of that famous matte medium mix on the edges of the track, and glue it down.

Ed

[cera2254]

I’ve used a combination of Ribbon Rail (?) 10” straight gauges and a 4’ level and I think it does a pretty good job.

[lvrr325]

I would think if you laid a straight line with a pencil, laid your cork with the square edges along that line, then used that as a track centerline, it would come out pretty straight. Then a yardstick or similar straight edge could be used to fine tune it.

I would use spikes at least as temporary holders. I find once ballasted the track does not move, but at the same time if you have to pull something back up it's not that hard to do, you can usually save the track and even the roadbed.

[edwardsutorik]

May 10, 2022 8:24:25 GMT -8 lvrr325 said:

I would use spikes at least as temporary holders. I find once ballasted the track does not move, but at the same time if you have to pull something back up it's not that hard to do, you can usually save the track and even the roadbed.

Yup.

I've even actually raised up some low trackwork off of the cork roadbed and reballasted. It worked very nicely. I just chipped the ballast out and replaced it once the track was re-aligned.


Ed

[riogrande]

Yes, as I mentioned earlier, draw a centerline and lay track (or cork and then track) on the centerline. That will get you 98% there. I tweak with eye to get it near perfect after that.

Here I've laid split cork roadbed on the centerline:

[joppasub]

Excellent work, Jim.

[sp8234tim]

Don't glue it down until after running on it & letting it go through heat cycles. It also depends on the room & temperature fluctuations. At a club in northern California (Napa) we could have winter with 40 to 110 degree days in summer & track moved around a lot. We used an Xacto blade (when above 70 degrees) & a brown Dremel cutoff wheel if below for gaps. After about 2-3 months the rail would stop moving (lots of agistments) & then we would glue it down. Patients is the key to good/strait trackwork.

Tim
Hanesworth
NVN #41

[riogrande]

May 14, 2022 17:10:20 GMT -8 sp8234tim said:

Don't glue it down until after running on it & letting it go through heat cycles. It also depends on the room & temperature fluctuations. At a club in northern California (Napa) we could have winter with 40 to 110 degree days in summer & track moved around a lot. We used an Xacto blade (when above 70 degrees) & a brown Dremel cutoff wheel if below for gaps. After about 2-3 months the rail would stop moving (lots of agistments) & then we would glue it down. Patients is the key to good/strait trackwork.

Tim
Hanesworth
NVN #41

Agree, don't glue the track down until after running it and letting it breath. The problem with modern track laying is most now glue their track down as they are laying it. You've high lighted a disadvantage of that method.

[slowfreight]

My experience, even living in the desert with temp variations, is that once fully ballasted using dilute white glue, the track stayed in place and did not kink.

The behavior of flex track nailed down or glued with caulk, yet not ballasted, is similar to 1:1 scale ribbon rail. Welded rail will kink if temperature swings too fast, unless you add rail anchors.

Rail anchors clip around the rail, up against the tie. It keeps the rail from moving lengthwise, so when it thermally expands or contracts, it does so width-wise. It also keeps rail on a grade from sliding downhill, which can even be a problem on jointed rail.

After nearly two decades, my ballasted track has not broken free or shifted.

[timmie]

I've found a simple 48" straight edge works every time

[edwardsutorik]

My experience with having a module exposed to 116F is that I should have had expansion gaps, as one of the rails blew out sideways.

So I installed such gaps.



Ed

[Deleted]

My track is actually the Kato track. I liked the appearance and absolutely hated ballasting; the ballasted track of my youth wasn't so good, and I didn't want to repeat that debacle.

Once we got the Kato track all laid out and assembled per my cadd track plan, we did let it "breathe" a bit while I ran trains. I quickly learned that un-glued track curves will wander a little bit ie slide over the pink insulation foam sheet. So first I glued down the curves using Liquid Nails so that they couldn't float anymore and were locked into position, and then I didn't worry if the tangents floated around a little bit because the curves were not moving anymore. Once I added simple desert tan paint and sand (into the paint while still wet) for my desert scenery base, the tangents became pretty well locked in but not everywhere.

I wasn't really trying for perfectly straight tangents--to me that's a whole other level of track laying. I was more concerned with not having horizontal or vertical kinks anywhere in the track plan.

As I've relaid a couple portions over the last 16 years to accommodate specific engines or rolling stock, now I do have a very slight horizontal kink, but it's not enough of a kink that the rolling stock has any issues.

Also, because I never soldered any of the Kato joints, it is as if I have the expansion gaps at the joints. You can see the joints move a little bit from winter (heated basement when I'm down there) to summer when the basement never gets much above 70 degrees. There are still a few tangent pieces that are not glued down or locked in place by scenery, such that they can float as the temperature changes.

If I was doing traditional trackwork, I would allow the occasional gap for expansion/contraction. It generally does not have to be much. A sixteenth of an inch here and there will work well enough most of the time. You don't want too big a gap, or I think it can result in excessive wheel plating wear.

[edwardsutorik]

For nickel silver rail, if you assume a 100F range of temperatures, the expansion gap would be .001" per inch. That is 1/32" per yard of track.

Since it's extremely unlikely you'll be laying track at the lower end of the range, say 32F, probably the way to go is to lay it at normal temperatures, and assume 50F up (and 50F down). Then it's 1/64" per yard of track, and the lower end of the scale will take care of itself.

I think 1/32" every six feet or so might be a good idea. But you probably shouldn't make the gaps in curves--only straights.



Ed

[Colin 't Hart]

May 16, 2022 17:14:20 GMT -8 edwardsutorik said:

For nickel silver rail, if you assume a 100F range of temperatures, the expansion gap would be .001" per inch. That is 1/32" per yard of track.

Since it's extremely unlikely you'll be laying track at the lower end of the range, say 32F, probably the way to go is to lay it at normal temperatures, and assume 50F up (and 50F down). Then it's 1/64" per yard of track, and the lower end of the scale will take care of itself.

And if my temperature fluctuates at most between 75 and 80, what do I need to allow for, if anything? Humidity does fluctuate a lot.

[jonklein611]

May 16, 2022 23:18:43 GMT -8 Colin 't Hart said:

May 16, 2022 17:14:20 GMT -8 edwardsutorik said:

For nickel silver rail, if you assume a 100F range of temperatures, the expansion gap would be .001" per inch. That is 1/32" per yard of track.

Since it's extremely unlikely you'll be laying track at the lower end of the range, say 32F, probably the way to go is to lay it at normal temperatures, and assume 50F up (and 50F down). Then it's 1/64" per yard of track, and the lower end of the scale will take care of itself.

And if my temperature fluctuates at most between 75 and 80, what do I need to allow for, if anything? Humidity does fluctuate a lot.

0.00005 per inch for a 5 degree temp delta.

So 0.005 inches of movement over 100 inches of track. Just leave some space at your rail joiner gaps. With humidity swings if you're using homosote make sure you seal it.

[stottman]

Thanks for all the tips. I might try spiking it down instead of caulk.

Using the centerline on the caulk isnt very good, as the Midwest cork itself isnt dimensionally consistent. .

[southeastern]

Hi, I use a 40 inch stainless steel rule when caulking down straight track, I let the rule sit on top of one rail and the edge runs against the inside of the other rail, using a tooth pick to push the rail flush with the straight edge, I work it till I'm happy. I'm talking flex track, Peco code 83. I measure out from two fixed points on the bench work to get the track in the right location so I don't need to do a center line. If I was to do a 10 foot long straight section I'd mark out some extra fixed points to measure from, and work the steel rule along the section. The most critical thing is to eyeball the track afterwards to make sure you didn't build in a kink. I use tin cans to weight down the track while the caulk cures.
Dave H

[lvrr325]

One thing no one mentioned is it may make a difference what brand and rail size the track is. I have had flextrack that was very hard to flex or curve and so once you got a bend in it it was hard to get rid of it. On the other hand the old Atlas Code 100 is very pliable and tends to straighten itself out if left alone.

[fr8kar]

May 26, 2022 10:10:49 GMT -8 lvrr325 said:

One thing no one mentioned is it may make a difference what brand and rail size the track is. I have had flextrack that was very hard to flex or curve and so once you got a bend in it it was hard to get rid of it. On the other hand the old Atlas Code 100 is very pliable and tends to straighten itself out if left alone.

That was why I designed the 3D printed curve tools. I had some weathered Micro Engineering flex that was nearly impossible to bend consistently. I printed the tool and in less than a minute had flex curved to the 48" radius I wanted.