What is a “Rail tracking system”?

Photovoltaic (solar) panels were mounted three ways:

• On fixed racks – simple, solid and inexpensive.  But fixed racks only allow each panel to capture about three-fifths of the available energy!  So fixed-rack systems take the most land, labor and equipment – panels, inverters and other components – to meet your energy needs, and thus are the most expensive way to mount solar electric panels.
• One one-axis tracking systems – tracking the sun east/west through the day but not north/south through the seasons.  One-axis tracking systems produce about 20% more energy (in kilowatt-hours) than fixed rack systems.
• On upright-pole two-axis tracking systems – tracking the sun east/west through the day and north/south through the seasons.  They produce about 40% more energy (kWh) than fixed-rack systems (depending on latitude and other factors).

The most productive of these is the two-axis tracking systems, but these systems have several disadvantages which have prevented their widespread use:

• High winds cause problems, because panels on the edge of each system are not supported. Upright-pole two-axis tracking systems are generally rated for winds 100 Kilometers per hour or lower.
• Stresses from the wind and from the weight of the panels are concentrated at the top and bottom of the pole. These concentrated stresses can lead to breakdowns.
• The mechanism for moving the panels is complex, with numerous moving parts, which can lead to failure.
• The weight of these systems requires a massive concrete foundation, which means excavation with heavy equipment. This adds significantly to the cost of upright-pole systems.
• Upright-pole trackers are not scalable;  that is, there are no mechanical components which are shared between two or more trackers.

A rail tracking system can move dozens of panels in synch, tracking the sun east/west through the day and north/south through the seasons, so energy production is maximized.

But unlike upright-pole systems, rail tracking systems are simple, durable and reliable: