Garden railways experience great temperature fluctuations every day. In some areas, temperatures can swing as much as 50-60 degrees in a single day. Throughout the year as we go through different seasons, we get even wider temperature ranges. These temperature fluctuations cause our railroads to expand and contract - the primary reason why we never attach our tracks to the ground and why they are floating on ballast like their bigger brothers.
The use of expansion track is vital only for the long sections of track. Track on turns and curves are fine as the track should float in and out as the rail expands and contracts. A portion of track that has 20 feet (6 meters) or more should use an expansion section. This prevents track from buckling in the heat or large gaps that the trains cannot cross without derailing, loosing power, or causing extra wear in the cold (winter/night).
Here are some guidelines that DCCWiki recommends: - Less than 20 feet, you may not need an expansion section, but it can't hurt. Not need until past 10 feet. - If you have 20 feet, put an expansion in the middle so you only have 10 feet at most between areas of track that can relieve pressure. - Every 20 feet of track for runs longer then 40 feet.
Examples - 10 feet - None needed. - 20 feet - One in the middle of the run. - 30 feet - one somewhere in the middle. If one end has a tighter turn into the straight section than the other, place the expansion section closer to the wider turn. - 40 feet - One 10 feet in from both ends, leaving 20 feet in the middle. - More than 40 - one 10 feet in, then every 20 feet.