Model Railroading is NOT fun

[OldEastRR]

There's a reason they have expansion gaps on steel bridges....and they look very prototypical.

[Smike]

Yup, fixing a kink is my project this week as well, and in the middle of a helix no less    I painted all of the woodwork in the Helix with a primer sealant when I built it (just to try to avoid this), but given the very low humidity with this cold snap the air is super dry and must have shifted something. Otherwise the temp stays as 60 all year long.

Also of note, all of my kink problems have been on hidden track which is mounted directly to the wood base vs track on cork.  I have to believe the cork absorbs some of the expansion/contraction

[ednadolski]

I have to believe the cork absorbs some of the expansion/contraction

Seems likely, provided the cork hasn't substantially dried out and become too inflexible.  On curves at least, it would allow the track some freedom to expand/contract radially.  With flextrack (particularly the kind with a loose/sliding rail) you might notice some changes in the gauge, hopefully tho not enough to impact operation.  (Another reason to check all wheelests are in proper gauge.)

all of my kink problems have been on hidden track which is mounted directly to the wood base

So did you mean that you've put down this track without leaving any expansion gaps?   I've been gluing my helix track straight onto the plywood, but every rail joint has a gap of about 20 thou or so.


Ed

[mmagliaro]

I learned this painful lesson on my PRR layout, which used to live in an unheated attic room that I had to warm up with space heaters during the winter to work up there.  Even on foam base with foam roadbed, and even with some expansion joints, I had two spots that kinked outward along long straight sections.

Painting, sealing, and controlling temperature and humidity are all good ideas, but not putting in expansion joints is just beating your head against a wall.  You are trying to "win" over the forces of nature, and that's just not going to happen.

Embrace the expansion joint!  It is your friend.

[JMaurer1]

The laws of thermodynamics...it's the LAW.

[Smike]

So did you mean that you've put down this track without leaving any expansion gaps?   I've been gluing my helix track straight onto the plywood, but every rail joint has a gap of about 20 thou or so.

When I started the Helix build I had long sections with no gaps, then I wised up, but too late on the lower turns. Nearly 20 months it has not been an issue until this recent cold snap due to low humidity.  Now looking to go back and cut gaps (I have more than enough feeders to support this) but its Atlas Code 80 and it’s a PITA to maintain the curve of the rail without at least non soldered rail joiners.

[randgust]

I'm in a very stable-temperature basement room with a dehumidifier in it, and I maintain between 40-60% all year.

All roadbed wood-every bit of it- is painted to seal against moisture.

Track is on cork - glued - and nailed down with track nails.   Either C80 or Peco C55; i.e. the 'tough stuff', and ballasted.

And it still moves.  Not much, but it still moves.  Most noticeable on the Masonite backdrops, that expand and contract about 1/32" on both ends of 4' sections, despite securing with metal strapping, tongue joints, and wood screw reinforcement.   

Every track has an expansion gap at least every 48", as it has to cross one of the modular tables.  And yeah, it visibly opens up those rail joints in the summer when it expands, and shrinks the masonite in the middle of winter (now) as the layout 'dries out' with the furnace and low humidity.   It definitely would rip the track loose without it.

One of my friends basement N layouts with unpainted homasote as the subroadbed and fully soldered rail was just just catastrophically springing loose.  That was a pretty terrible combination.   Our display-window office HO layout is even worse as it varies from below freezing to over 100 degrees, and I finally just let the curves float a bit as ballast kept loosening anyway.   You couldn't hold it.

Embrace the gap.... it's just as much of a problem on 12"=1 foot.  You're close to the Cuyahoga Valley, where the lack of shoulder ballast and the 'upgrade' by CSX to welded rail between Cleveland and Akron created a legacy of 'trackulence" that they still have to deal with on CVSR - welded rail heat kinks in the summer.   They have most of it beat now, but man, it was a mess there for a while.
http://www.transportus.org/2015/05/heat-kinks-or-what-i-learned-sitting-on.html

[nkalanaga]

Atlas code 80?  On hidden track?  Get some ME spikes, either the 1/4 inch or 3/8 inch, and spike about an inch of track, through or between every tie, on either side of the gap.  If it's real wood you can probably do it with just a pair of needle-nose pliers.  If you used plywood you might have to drill pilot holes, and if you go through the ties, rather than between them, you certainly will.  On hidden track I'd spike between the ties, since nobody will see it anyway, to avoid damaging the ties.

Do this on both rails, at every gap, and the rail should be able to slide enough to avoid kinks, while staying in gauge.  Even better would be to stagger the joints in the two rails, in which case the uncut rail MIGHT be able to get by with fewer spikes.  But spikes are cheap, or at least they were when I bought mine, and keeping the rails in line is worth a little extra work.

[Smike]

Atlas code 80?  On hidden track?  Get some ME spikes, either the 1/4 inch or 3/8 inch, and spike about an inch of track, through or between every tie, on either side of the gap.  If it's real wood you can probably do it with just a pair of needle-nose pliers.  If you used plywood you might have to drill pilot holes, and if you go through the ties, rather than between them, you certainly will.  On hidden track I'd spike between the ties, since nobody will see it anyway, to avoid damaging the ties.

Do this on both rails, at every gap, and the rail should be able to slide enough to avoid kinks, while staying in gauge.  Even better would be to stagger the joints in the two rails, in which case the uncut rail MIGHT be able to get by with fewer spikes.  But spikes are cheap, or at least they were when I bought mine, and keeping the rails in line is worth a little extra work.

That's pretty much the way I did it on the upper levels of the helix when I realized my mistake, the key as you mentioned is to stagger the joints on each rail. You still have to spike it, as Atlas code 80  flex just doesn't hold its shape. I also supplemented non soldered rail joiners that can slide a bit. If I had to do it all over again, I would have installed floating Kato snap track in the helix (Wouldn't even be a question)

[nkalanaga]

A hidden helix would be one place I'd consider Unitrack or similar roadbed-track.  Appearance doesn't matter, the curves would be precise, and it shouldn't ever fail.

[Chris333]

The blog post I linked earlier. The guy bought a humidifier and put it under the layout. Kink went away:
http://blog.thevalleylocal.net/2018/01/the-20-difference-goff-brook-trouble.html

[peteski]

The blog post I linked earlier. The guy bought a humidifier and put it under the layout. Kink went away:
http://blog.thevalleylocal.net/2018/01/the-20-difference-goff-brook-trouble.html

That just confirms our speculation that the problem is mainly with the wood drying out (and shrinking) than with the metal expansion/contraction.

[narrowminded]

Let me add something to this conversation.  I have a new situation that has surfaced since the extreme cold, therefore extremely low humidity, that we've had over the last week or so and it seems to be from very closely fitted styrene roadway. 

There is a straight road the length of the door with two crossing breaks at one end therefore a decent straight run without breaks.  Running trains last night I noticed some bumping at the one crossing just before the long run.  It acted like some of the issues I had when I first bought this layout with switch flangeway clearances as well as a track gauging issue at the other crossing.  It was the only track gauge issue anywhere on the board.  I attributed that to a very tight forced fit that had just squeezed the rail.  I lifted the road piece, trimmed the edge, moved the rail back into gauge, and then added a few strategically placed drops of CA to assure it stayed.  That has been good since. 

But now a similar situation has surfaced on the other crossing.  The short section of track just as it crosses the roadway has narrowed, evidenced in performance of locos through that section and then (unnecessarily) confirmed with the NMRA gauge.  In light of this discussion and a cursory inspection I'm HIGHLY suspicious that this is the same issue but instigated by the low humidity and the rigid, closely fitted roadway.  It also made me wonder if that may have contributed to the original problem.  Either way, it might be a further word of caution to folks using styrene roads up against rail at crossings.  An extra look and thought about the installation might suggest a gap needed there just as much as is needed in the rails.  I'll also be looking at the rail gaps although no performance issues have appeared elsewhere.  Hope that helps somebody.

[nkalanaga]

Yes, I can see where you might have that problem with a styrene road.  The wood under it shrinks, but the styrene won't.  We usually don't notice the benchwork shrinking across the track, because the track itself is so narrow, but here the entire shrinkage is concentrated on the track.  I hadn't thought of that problem before. 

[narrowminded]

Yes, I can see where you might have that problem with a styrene road.  The wood under it shrinks, but the styrene won't.  We usually don't notice the benchwork shrinking across the track, because the track itself is so narrow, but here the entire shrinkage is concentrated on the track.  I hadn't thought of that problem before.

That's what seemed evident.  Today I decided to dig into it and see what was needed.  It was as thought, tight as could be and the narrowed rail section was literally just the width of that roadway, not more than 1/8" beyond on either side.  But to be fair, there was one more thing that was discovered. 

The crossing was a very nice wood piece that I was able to save but when it was originally installed, it apparently sat a little high on the spikes so the ties/ spikes were sanded down to fit the crossing.   Well, that had the rail spikes virtually removed and the rail not very well secured as you might imagine.    It had worked fine up until last week but then the extreme weather occurred and the additional strain applied was more than it could handle.  And if it hadn't given there where would it have shown up?   Who knows but it has to go somewhere.  Maybe I'd have had a track buckle.

I was able to fix the whole thing good as new by moving the rail over and adding a few drops af CA at each tie/ spike position, beveling the underside of the wood crossing piece to clear those, and then remaking the outside rail to road filler strips and this time with a little bit of room for movement.  I didn't leave a lot this time because I think we're at the one extreme but if there's a lesson to be learned, it's to look over an installation for these potential pitfalls and if it's in the height of the humid season, maybe leave a little extra room. 

While I was at it I looked over the rail joints for gaps and saw very little if any in most of them.  But I've also not had any problems elsewhere AND it's probably the worst it will be right now.  I will watch them when the season changes and expect to see some opening up a little.  I also may get a humidifier, in part because we have talked about doing that anyway for all of the normal reasons.  This gives me one more.    Hope that helps somebody.