G Scale Model Train Forum banner

1 - 20 of 52 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
I am building a layout in Arizona with code 250 brass track. Average summer temps, 100+

I am using about 500' of track and battery power. The track will be floated in ballast and not directly secured to roadbed to allow movement.


Would it be better to use broad curves or straight sections to minimize movement of rail from expansion.


My thought is that if I use broad curves the rail will expand and push the curve horizontally rather than buckle the track if I have long straight sections.
Or does it matter?



Ben
 

·
Premium Member
Joined
·
116 Posts
By all means put some gentle curves in your long straights. I'm in No. Calif. and we get some 100+ days here. I've got a 80' straight section with some large radius curves in it, all just "floating" in ballast. On a hot day the track will move as much as 1/2" from side to side. I'm using Aristo 332 brass track, and have removed the screws attaching the tie strips to the rails, so the rails can move freely in the tie strips. Track has been down for a year and all seems o.k. Best wishes on your layout construction.

Joe McGarry
 

·
Premium Member
Joined
·
5,334 Posts
If expantion and contraction are a concern The rail clamp people make "EXPANTION JOINTS" for Rail

They work quite well.

If you want some Ideas Contact Duncan of the Sundancer Rail Road . He lives in Jillbert. ( Gilbert) That is on your side of the desert. He has a great RR.
 

·
Super Modulator
Joined
·
20,525 Posts
I have a friend in Scottsdale, he uses the "expansion tracks" (not the expansion joiners) from SplitJaw... they do the trick on long straights, they come in several versions, get at least the ones that move 1/2"... that will solve the problem on straights.

Regards, Greg

(Jillbert?)
 

·
Premium Member
Joined
·
5,334 Posts
Posted By Greg Elmassian on 10/27/2008 11:05 AM
I have a friend in Scottsdale, he uses the "expansion tracks" (not the expansion joiners) from SplitJaw... they do the trick on long straights, they come in several versions, get at least the ones that move 1/2"... that will solve the problem on straights.

Regards, Greg

(Jillbert?)

One of my customers was printing a Real Estate add. They had run off 2500 sheets of this 4 color job with coating. Cut it and folded it when someone noticed the some one had spelled Gilbert as Jillbert.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #10
I talked to Duncan about 2 years ago. I will have to go see his layout.
I am looking into the expansion joints. This weekend I got the roadbed down, it needs to be leveled but, I am getting close to putting track down.
 

·
Registered
Joined
·
467 Posts
You need to talk to Dennis Serrine, the Palo Verde and Southwestern RR. He is in Mesa, off McKillips. He has some of the biggest turns you will ever see anywhere. I do believe that he has expansion joints, as well as Hillman clamps at every joint, and has no movement. Check him out, you will not be sorry.
Paul
 

·
Premium Member
Joined
·
237 Posts
Big gentle curves everywhere and just letting the track float is the simplest way to allow for track expansion. You will want expansion track if you want straight track.

Terl
 

·
Premium Member
Joined
·
381 Posts
My layout is indoors, and therefore I don't know what I'm talking about when it comes to outdoor layouts. Howeve, I'm not convinced that thermal expansion is as much of a problem as it's claimed to be. A couple of years ago I was thinking about adding a thermal expansion calculator to my Handy Converter program, but after some research I decided not to do it because of my conclusion.

Here's some info: the coefficient of thermal expansion for brass is 19 parts/million per degree Celsius. For an example, let's calculate the effect of a 100 degree Fahrenheit temperature change on brass track. 100 degrees F is equivalent to 55.6 degrees C, so our formula would be 19 X 55.6 / 1000000 which equals .0010564 feet per foot of track. For 100 feet of track, the expansion would be 0.10564 feet, or about 1 1/4 inch.

Stainless steel is less of a problem as its coefficient of thermal expansion is just 17.3. A 100 degree F change on 100 feet of stainless steel track would be about 1 5/32 inch.

Aluminum is a little worse; it's coefficient is 23. A 100 degree F change on 100 feet of aluminum track would be a shade over 1 1/2 inch.

Again admitting I have no real outdoor experience, these numbers seem small to me. An inch of movement in 100 feet of track from deep frost to scorching sun? I would think that keeping a few rail joiners unclamped would allow for this kind of movement. I ask someone who has had an actual problem with thermal expansion tell me how flawed my conclusion is!
 

·
Registered
Joined
·
1,167 Posts
I remember Jack T. posting this pic. Its aluminum rail which is, I think, the worst at expansion but illustrates the point -



-Brian
 

·
Premium Member
Joined
·
348 Posts
I live in Mesa, Az and don't have any problems with expansion of the rail/track at all. Of coarse all of by track is glued down to the concrete roadbed though.
 

·
Premium Member
Joined
·
5,620 Posts
I would use the expansion rails as they work best to relieve rail expansion. Dennis Serrie track is screw down to the road bed. He has very long straight aways and Lazar line the track prior to screwing sown. Brass track will expand more than SS rail. These two methods work best in your part of the country. Here where I'm at we often reach 100 degree days also but I use all SS track with no expansion joint. Track is all free floating. The track is well surfaced , tamped and lined and a full crib of ballast is a must as shoulder ballast is. You also want the ballast to fill the void on the under side of the tie. This is a must to keep rail movement to a minimum. The screws that hold the rails to the ties is a type of rail anchor that also help prevent rail movement. Romoving these make your rail move more than it should. Later RJD
 

·
Registered
Joined
·
14 Posts
Discussion Starter #17
Would you also recommend that I use the rail clamps?
I have read in a few posts that layouts which use battery power only do not use rail clamps but, I don't know if they are only in ballast or secured in other ways (spike through ties, screwed down, etc..)
 

·
Premium Member
Joined
·
170 Posts
I live in the Western part of the state (AZ) near the AZ. / CA. border. It routinely reaches 120 plus here. I have a couple thousand feet of mostly ss with some brass. I run battery power. I have dealt with the expansion problem for 4 summers now. It is definitely a problem on straight sections of any length. I use Split Jaw & Hillman clamps and I make my own expansion tracks as the store bought are a little two pricey for the amount of them I use. My track is free floating on my ballast. I got the idea of making my own from a GR article on Gen Bangs RR. I use a foot of track cut in half. I then grind the ends to half there width. I grind back about 1 & 3/4 inches to get around ¾ inch of travel in both directions. I allow the rail to move freely in the ties and mount the ties to ¼ inch backer board or red wood to stiffen the joint. Brass is far easier to work than the ss but I have good results with booth.
Best, Ted







 
1 - 20 of 52 Posts
Top