tag:blogger.com,1999:blog-12532342.post-1146811636295580682006-05-05T06:47:00.000Z2006-05-05T06:47:00.000ZAfter the question that you raised about warm-weather countries in the previous post, I asked some fellow enthusiasts how this was handled in Israel, where the outdoor temperature can reach 40 or higher some days of the year.<BR/><BR/>The answers that I got pretty much fit with what both LUL and Metronet are saying. The practice (at least in many countries) with welded rails and concrete sleepers is to heat the entire length of rail up to the highest forseen temperature and then weld it to the sleepers. I'm assured (much to my disbelief) that this ensures that even when the rails expand and contract, they do so in line with the gauge. There are still expansion gaps between the welded rails every 100 metres or so, but these do not cause "clicketty-clack" as they have a diagonal profile.<BR/><BR/>Additionally, they claim that there is importance to the weight of the sleepers used and the amount of ballast, as well as the frequency with which the ballast is respread (if that's the correct term?).<BR/><BR/>For a change I can understand Metronet's point-of-view vis-a-vis having enough time to treat the rails adequately when they were welded, as the heating process described above sounds pretty time-consuming.alantanhttp://www.blogger.com/profile/02187586644057915993noreply@blogger.com