Quote:
Originally Posted by Busy Bee
Technical Question:
Why is the trackway sometimes, for lack of better terminology, girder rail encased in concrete, but at other times standard rail on concrete ties? Seems like it would have been much cheaper to use standard rail/ties or rail/concrete base and maybe encourage grass or groundcovering (Barcelona, Lyon, etc.). Also would have brought a nice strip of green to a very concrete intensive place.
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It seems like they're using an attractive granite ballast instead of limestone - which also extends the life of the track. Limestone is universally recognized as a terrible ballast material, but often used on transit/commuter rail lines.
If Metro ever decided to stop using herbicide on their rights-of-way, they'd soon get all sorts of drought-tolerant vegetation to soften the edges. Germany banned herbicides, so their tracks and railyards have all sorts of growth between tracks, etc. The plants actually soak up water, which lessens the load on the drainage system, and their roots reduce erosion in the ballast. Usually we think of killing weeds as a necessary part of maintenance, but it's purely a matter of aesthetics. The vibration of the trains passing should create enough disturbance to prevent weeds from growing to any appreciable size, and if it doesn't, you can send a guy out periodically with a weed-whacker.