CWR can be stretched along straight track, which in many areas of the country is endless miles. Curves, however, do not work well with rail under tension. The spikes pull out. That is why the rail expansion joint I showed in the previous post is used on curves. It eliminates the tension.
The South Shore Line in northern Indiana has had welded rail for a few decades now, and you can drive parallel to most of it. As you do, you will see every few miles one of the rail expansion joints. If you know what you're looking at. The thing is that although the line SEEMS to be straight, it is not. Rail under tension would be a big problem on the curves. And that's basically why we can't use tensioned rail on our model layouts. We don't have enough straight track. You could easily do it if you have a scale 10 mile run of straight track. Let's see, um, 52800 feet divided by 64 = , um, ticka ticka 825 foot basement. OK, maybe you could even do it with a 200' straight run....... Darrell --- In [email protected], Robert Frascella <frascerj@...> wrote: > > Ed, > > In the real world Continuous Weld Rail is laid at a temperature where the > maximum expansion is expected to occur. This is precalulated for the > region or area of the country where the track is located. If the proper > temerature of the rail cannot be achieved, then the rail is heated until it > expands to that temperature then welded together. Because steel has > tremendous tensile strength, when it cools there isn't an alignment problem > if the rail is properly secured. The contraction during cooling is more or > less absorbed by the rail. (Problems sometimes occur when there is a > defect in the steel and the cooling can cause a rail to break, but that's > not typical) Heat expansion is the bigger problem. > > I guess we could use this principal in model railroading, but then we'd > melt all those plastic ties:) > Bob Frascella > Wenham, MA > > > On Mon, Mar 12, 2012 at 2:25 AM, Ed <Loizeaux@...> wrote: > > > ** > > > > > > > Not much of the track is soldered together > > > This first kink was with SHS flex track. > > > I wonder if the size of the rail has any effect on the expansion. > > > > The material the rail is made from will determine the amount of expansion. > > Different materials will expand at differing rates. > > > > > > > I tried to not go end to end tight on the rails. I > > > guess the rails will show be where I could have left more space! > > > Bill Lane > > > > You might want to visually inspect those "former" gaps on a warm/hot day. > > If the ends of the rails now touch, that would be a good place to cut a new > > larger gap before the pressure builds up and leads to a kink. > > > > Question: In the real world, how do RRs prevent heat kinks when welded > > rail is used for l-o-n-g stretches of track? With welded rail, there are no > > slipping expansion joints -- or are there? > > > > Cheers...Ed L. > > www.sscale.org > > > > > > > ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/S-Scale/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/S-Scale/join (Yahoo! ID required) <*> To change settings via email: [email protected] [email protected] <*> To unsubscribe from this group, send an email to: [email protected] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
