Date: Fri, 16 Dec 2011 00:21:23 +0100
From: weberwu
Subject: Single point of failure in the Berlin Train System

The Berlin light rail train system, plagued by problems for years,
demonstrated today that it can, indeed get worse. Many cars have been
taken out of service for all sorts of ailments, and having pruned the
maintenance shops and the drivers to a bare minimum, there is no room
for dealing with problems. And there have been problems galore.

Berliners joked that it could not possibly get worse, but today (15
Dec 2011) the S-Bahn proved that it could, indeed, because it has a
single point of failure. All switches, all electronic signals, all
information is centralized in one station in Halensee. And the
electricity went out during a routine test of the emergency electrical
system today, according to RBB [1], a local news station. The
emergency system did not kick in - and then nothing worked.

Only two train lines that still have analogue signals and switches
were in operation, the rest was out - and the central operations was
also affected. They had no information on where the trains were.

Many people were trapped in trains stranded between stations. Angry
passengers opened the doors, got out and walked the tracks to the
nearest station, continuing by bus, subway, or taxi.

It took about 3 hours after electricity was restored to have some sort
of traffic running. The Internet information page by the S-Bahn was
down, the server was not able to cope with the traffic. Customers
used Twitter to announce trains in motion, helping people to find some
way to get to work or school.

[1]
http://www.rbb-online.de/nachrichten...sfall_bei.html

Prof. Dr. Debora Weber-Wulff, HTW Berlin, Treskowallee 8, 10313 Berlin
Tel:
+49-30-5019-2440 http://www.f4.htw-berlin.de/people/weberwu/