Green track

 ( Fills ) 

A light rail project in Sydney, Australia identified green track as requiring 81% less concrete compared to embedded track.

The cooling effect of the green surfaces, particularly in summer, lowers the temperature of the rails themselves, reducing the risk of buckling. The city of Dresden estimates that their total installed capacity of green track has a cooling effect, reducing the temperature by for of air per year.

Green tracks, particularly planted with endemic plant species, have positive impacts on the local biodiversity, such as the use of wildflowers that serve as food sources for bee, and providing habitats for insects.

• Track with high vegetation, or top-of-rail (TOR): Grooved rails are placed on , and the surrounding space is Fill dirt up to the grade of the top of the tracks. This technique provides the best noise abatement and a visually uniform green area, as only the track surfaces are visible. The sides of the tracks are generally protected with cavity filler blocks, to prevent direct contact between the rails and the soil, keeping the fasteners clean and preventing or slowing corrosion. The soil must be removed during track renewal operations. Soil moisture leads to corrosion in the track and fasteners, and both must typically be replaced during renewal. Because the fasteners are below the surface, it is more difficult to inspect them. The railway area is more difficult to recognize as a dangerous area, and additional protections need to be taken against stray currents. Track with high vegetation can also be crossed or driven on in exceptional circumstances.

• Track with low vegetation or foot-of-rail (FOR): Concrete sleepers are placed upon longitudinal concrete beams, and the space in between the sleepers is filled with topsoil instead of track ballast, with vegetation only reaching the base of the tracks. This has a reduced sound dampening effect, and the uniform green area is visually interrupted. However, inspection and maintenance of the rails is easier and the fasteners corrode much more slowly, as they are not constantly exposed to moisture from the soil. Switches and sensors can be mounted on the tracks, and there is better control over residual electrical current flowing into the ground. This design also allows for normal Vignoles rail, which are typically cheaper and easier to maintain than grooved tramway track.
• Track with mixed-level vegetation: This solution incorporates low vegetation between the rails and high vegetation outside. This allows for easier inspection of the rails, but creates a visible trough in the green surface area, where dead leaves and debris can collect.

The ground cover requires a stable track bed construction, where the track geometry will not shift after construction. This is commonly accomplished with ballastless track. The addition of soil to track ballast would reduce the friction between the individual ballast stones and make it easier for the track to shift out of place, while making adjustments and corrections more difficult. At the same time, extensions and changes are more involved than with conventional track ballast.

The soil surrounding the tracks is planted with grass or other suitable ground cover plant. In comparison, grass tends to require higher maintenance, such as mower and irrigation, and a soil layer of at least . In particular, Shade tolerance and drought-tolerant species are chosen depending on local conditions; sedum is a common choice, as it requires a substrate of only . The space between the tracks can also be filled with Permeable paving instead of soil. The city of Braunschweig, Germany, together with the Julius Kühn-Institut, developed a mixture of endemic grasses and wildflowers suitable for green tracks that will also provide a habitat for Bee.