Large Scale Central

Brass track expansion problem

I have finally finished laying my track and adding the ballast, but! I have an area, approximately 6 feet long, that is in constant sunlight, and the track appears to be expanding and contracting in this area, to the point where the movement coming from this is affecting the track level. I have added a screen of landscape cloth to see if the track will be more stable without the constant sunlight, and it seems to be working. The bad side of the landscape cloth is that it is definitely not prototypical. My intention is to build a small mountain, but would like some hints or direction on how to do this. It would be roughly 6-8’ long, and perhaps 2’ high, but, I would make it a false mountain in that I would be able to access it from the back side in the event of derailments, etc. I would like to make this 1/2 tunnel look like a mountain, complete with portals, from the operators side of the layout. From the backside it would be open, to allow for access. Has anyone ever built anything like this? Can anyone point me in a direction on how to do this? Needless to say, any suggestions and/or direction are greatly appreciated.

You could try an expansion joint.
http://www.railclamp.com/displayCategory.jsp?categoryId=36&vId=149588

I saw somewhere a while back where someone built a mountain using the hardshell technique of smaller scales. He built a frame using pressure treated lumber. Shaped it with hardwear cloth. Then using strips of an old sheet soaked in cement he built his mountain.

Roger

Noel,

Keep in mind that ALL of your track is expanding and contracting with temperature, not just the track in the sunny area. The reason you see it there is the higher temperature differential from night to strong sun day.

Brass expands at a rate of .0000104" per inch of length per degree of temperature rise. So if you have a 120" long straight track you installed it at 20 degrees F, and the temperature is now 80 degrees F, the additional length would be 60 (temperature rise) X 120 (length) X (.0000104 coefficient of expansion) = .07488 ~ or a little over 1/16". Now look at the length of your total pike and see how that equates.

My best advice would be when assembling track, leave about a credit card thickness at each joint to allow the rails to expand without affecting your right of way.

Bob C.

Thanks Bob-
Good data!
I avoided the entire expansion topic by “floating” my track by setting it on a concrete roadbed. When the expansion occurs, however minor, the entire track moves slightly. Check my reasoning: The problem arises when any portions of the track pattern are secured so the movement can not be collective.
Wendell

I have 2 questions
What track are you using(and sorry if I missed that)
If a certain type did you remove the screws securing the track too the ties?

Jim C has done an expansion the Hedgeapple & RioGram using a hardshell method. There’s a thread on MLS.

2010 Hedgeapple & RioGram Expansion Log

is towards the end of the log.

Again, thank you for all the suggestions.
We seem to have solved the problem, and have presently constructed a covered area over the tracks where there is a huge differential in temperature. We will be constructing a “3/4 tunnel” in the future, as this cover is only temporary, but we can run trains. The layout is now operational with both track and battery power. As we are interested in keeping things as simple as possible, the two reverse loops will only run with battery power, as there is a polarity issue that would require extensive work to correct. Track powered running between the mains is not a problem, only the reverse loops. We have run into a small problem, one of the Aristo-Craft Train engineers is in need of repair as we can only get it to go in one direction, as the “fast” button and the “emergency stop” button are the only buttons that work, the “direction arrows” and the “slow” buttons do not work. This is a bit of a problem, as the classification yard is connected only to loop #1, so we can’t get a train under track power to get to the track powered loop #2. We will be dealing with this issue today and tomorrow.
To review, all of the track is Aristo-Craft .332 brass flex track. It all “floats” on the top of, effectively, a 450’ deck. Track is secured with “crusher fines”. All mainline switches (between the mains) are #6, all other switches are #4. Minimal grade of <.05%. Two main lines, each 750’, rail yard and sidings 300’. It takes approximately 11 minutes to complete 1 loop on either of the mains, at a scale speed of 50 mph. We haven’t done it yet, but I will be trying to see what happens when I put 3 trains out at a time on a loop, roughly 3 minutes apart. Hypothetically, we should be able to run 3 trains at a time on each main, but not sure if I would want to do that myself.
We had set a goal of July 1st as the “Golden Spike Day” and we beat it by a week.
Again, thank you for all your help.

When I built my layout I was advised to leave 1/8-inch between sections. I used rail joiners and the expansion and contraction led to a lot of derailments. This year I have been installing rail clamps and the derailments are gone. I let my track float here on the desert. With our heat you can get noticeable movement. What size transformer are you using to run three trains?

Thank you.
I am using multiple 15 amp/24 volt power supplies, and all lines are double fused. All 1900’ of the track are connected with rail clamps. Hopefully the problem with the major difference in temps has been dealt with, the rest of the layout is in the shade, most of the time (just makes for a mess).

I would say ypu have plenty of power. Out here on the desert the biggest movement has been at one end in the sun. We had several days where it was 110 and in the 60s at nigt. The third day the track moved four inches and the main;ine is only about 500 feet long! With the rail clamps I haven’t seen one separation – so far!

Correct? If ALL of the track, connected tightly, can “float”, then the entire track is expanding and contracting. The problem of damage occurs when portions or all of the track can not float so the contraction force causes warpage.

Doug Arnold said:
and the mainline is only about 500 feet long!
You're a funny guy :D Ralph
Wendell Hanks said:
Correct? If ALL of the track, connected tightly, can "float", then the entire track is expanding and contracting. The problem of damage occurs when portions or all of the track can not float so the contraction force causes warpage.
Correct. in Noel's case none of the track is fastened down however in my experience I have found it better to fasten the ties on the straight's with no screws securing the ties too the rails. This allows the expansion and contraction to push in the curves and float in the ties.

The pnly screws I have are in the middle of a bridge and two trestles and that’s just through the ties. But even though the track floats the only expansion I have seen is at the far east end. Physics doesn’t seem to work on my layout. Must be those UFOs!

If you are really worried about expansion, get a couple of the expanding rail sections from Split Jaw, that will definitely help. I have a friend in Scottsdale, and he had long straightaways, about 60 feet, and was getting sun kinks, this fixed it.

Dennis Serrine had a box of them when I visited his layout in Phoenix.

Regards, Greg

David Russell (post above), I think has targeted the problem with “floating” track: In each section of LGB/Aristo track, some of the ties are screwed to the rail – turnover a section of track and note the small screws intermittedly set into some of the ties. So the expansion is limited or hindered by those attachments. The remedy is to unscrew those ties.
QUESTION: Would not simply unscrewing one rail resolve the problem of expansion hindrance?
Wendell

David Russell (post above), I think has targeted the problem with “floating” track: In each section of LGB/Aristo track, some of the ties are screwed to the rail – turnover a section of track and note the small screws intermittedly set into some of the ties. So the expansion is limited or hindered by those attachments. The remedy is to unscrew those ties.
QUESTION: Would not simply unscrewing one rail resolve the problem of expansion hindrance?
Wendell

Wendell, After visiting Dave Russell’s layout I followed his recomendations on track laying. The first loop I have has all the screws removed from the track/tie connection.
We shall find out the answer to your question by next year as I’m in the process of laying a second loop and had your same thought. Therefore, I only removed the screws from one rail.

Free floating track soldered together with all the track/tie screws removed has not given me any problems to this point and I live in the York Pa area.

Wendell Hanks said:
David Russell (post above), I think has targeted the problem with "floating" track: In each section of LGB/Aristo track, some of the ties are screwed to the rail -- turnover a section of track and note the small screws intermittedly set into some of the ties. So the expansion is limited or hindered by those attachments. The remedy is to unscrew those ties. QUESTION: Would not simply unscrewing one rail resolve the problem of expansion hindrance? Wendell
Wendell, All:

I have never seen a screw in LGB track / tie structure. There are tabs on the slip connectors that are bent down into a slot on the tie, but no screws.

IMHO, just allowing expansion room by putting a slight space (~1/16 to 3/32") will take care of virtually all thermal expansion problems, at least on LGB track. I have never had an expansion kink on my track. It is connected with a combination of the original LGB joiners and Hillman clamps and is free floating on ballast. Our temperatures seasonally range from lows in the high teens to highs of 110+.

Happy RRing,

Jerry