Portland is well-known for having one of the best light-rail systems in the country. Through an efficient combination of train and streetcar - served by a great bus system, makes getting around the region sans car relatively pain free. A recent post from Inhabitat definitely struck home a point regarding a retrofit that could make this green transportation system even literally more green. As opposed to a car, rail only makes contact at two thin points along the track alignment. By looking at these corridors on which the trains run - which have interstitial areas that are typically paved with a variety of surfaces, there is an opportunity to create less impervious surfaces through the incorporation of greenery.
Could Portland's rails evolve from this...
:: image via IgoUgo
...to something more like this?
It's not a surprise that this is a common practice in Europe, which is covered extensively in the Inhabitat post from around the continent. The images are self-explanatory and seem quite simple, and are summed up in the post: "...these swaths of green provide a host of benefits to any urban area, like reducing urban heat island effect, providing a permeable surface for storm water to infiltrate, and reducing pollution. And did we mention that it looks so much prettier than concrete or asphalt?" Agreed.