Welcome to European Tribune. It's gone a bit quiet around here these days, but it's still going.
Display:
Apparently it's not about the pantograph noise. The more distance between rail and wall, the higher it must be to stop the noise. Repairs and maintenance works need room though. Here is an article about tests of a removable wall that sits close to the rail and needs only a height of 70cm. http://www1.wdr.de/themen/panorama/laermschutz110.html
by Katrin on Mon Sep 17th, 2012 at 05:10:22 PM EST
[ Parent ]
The more distance between rail and wall, the higher it must be to stop the noise.

Because of Fresnel diffraction. See also Fresnel zone.

At a given distance from the wall, the noise intensity decays exponentially with the distance down from the height of the barrier. So each metre of additional wall height helps. A lot.




I distribute. You re-distribute. He gives your hard-earned money to lazy scroungers. -- JakeS

by Migeru (migeru at eurotrib dot com) on Sun Sep 23rd, 2012 at 04:06:53 AM EST
[ Parent ]
The more distance between rail and wall, the higher it must be to stop the noise.

Good point, more relevant than my pantograph noise wild guess (see upthread).

a removable wall that sits close to the rail and needs only a height of 70cm.

Advance notice: last week, I was at the InnoTrans in Berlin (the world's biggest rail trade fair, held every two years), on which I shall report in a diary (hopefully by this weekend). There, I saw what looked like a further development of the system shown in the article you link: there is that noise-absorbing part (which is 55 cm high above the top of the rail and doubles as walkway for track workers) and there are parabolic noise-reflecting acrylic glass railings on the outer side.

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Mon Sep 24th, 2012 at 01:51:51 PM EST
[ Parent ]

Display:

Occasional Series