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Technical Discussions
Rolf Diederichs
NDT.net, Germany, Joined Nov 1998, 617

Rolf Diederichs

Joined Nov 1998
04:18 Jun-11-1998
dpa- News Message: NDT Public Affaires

I would like to inform this forum on recent NDT public affaires.

The below text released by the German's Press association (DPA) is not
very technical, however, it covers themes like probability of detection
or ethics of NDT and shall be interesting for everybody who works in
the field of NDT.

A number of TV channels wanted to send a camera team but I suggested
that footage of the actual WebSite would be more appropriate, also we
may prepare a RealAudio file soon (virtual interview).

It is not our intention to blame here NDT people in such early stage of
investigations. Althought all of us know to good how often NDT solutions
are acordingly to minimized budgets released by the managment.

- Rolf Diederichs

dpa- News Message

Hamburg/Eschede (dpa/lni), (translated by NDTnet)

- Another expert has blamed the Deutsche Bahn for last week's ICE
accident. Although the DB was aware that rail wheels of this type should
be tested with ultrasound every 2-3 days, the implementation of such a system
was not pursued aggressively enough, Dipl.-Ing. Rolf Diederichs, publisher
of an Internet journal about ultrasonic testing (www.ndt.net), told DPA on
Wednesday. "Even though the necessity for more stringent testing was known,
there seemed to be no sense of urgency to do anything about it, although
state of the art equipment and technology were available, " said Diederichs.

Hegenscheidt pioneered a system in 1992, which was integrated into the
Hegenscheidt-Diagnostic-systems of Hamburg in that same year, and in Munich
in 1994. This system is used to test the wheels of those trains every few days.

The DB had originally planned to establish this system for the ICE train
wheels officially. According to Diederichs, "They knew that during operation,
defects can occur that can break the wheel, otherwise, why would they even
have been considering applying the testing procedures to address that?"

The manager of Hegenscheidt, Klaus-Peter Schwarz, confirmed that the
systems have been installed in Munich and Hamburg, in 1994, and 1992,
respectively. These systems consist of three modules: roundness measurement,
profile measurement and the ultrasonic unit to detect the cracks. However
the ultrasonic unit showed evidence of unreliability, because signals coursed
by "irrelevant surface cracks could make the important cracks invisible."
For that reason the ultrasonic unit was switched off in Hamburg 1993 and in
Munich it was not used for continuous

However, according to Schwarz, the unit was undergoing further testing.
"From these results a completely new ultrasonic unit for crack detection was
developed. It will be tested in the next three weeks in Hamburg."

Currently experts are discussing better solutions in the online-Forum of the
professional journal «The e-Journal of Nondestructive-Testing and Ultrasonics»

In addition to other articles, the site has published a lecture given by DB
employee Hartmunt Hintze, who points out the problems of the Hegenscheidt-system
and an outlook on future improvements. "Meanwhile the technical modifications
have been applied, and the trials are in preparation," he says.
(dpa/lni hu yy ek) (translated by NDTnet)

In German:

Hamburg/Eschede (dpa/lni) - Im Zusammenhang mit dem ICE-Unglück
von Eschede hat ein weiterer Experte Vorwürfe gegen die Bahn erhoben.
Die Bahn habe zwar von der Notwendigkeit einer Ultraschallprüfung der
Radreifen im Zyklus von zwei bis drei Tagen gewußt, die Entwicklung
eines entsprechendes Gerätes aber zu nachlässig verfolgt, sagte
Dipl.-Ing. Rolf Diederichs, Herausgeber einer Internet-Zeitschrift
über Ultraschallprüfverfahren (www.ndt.net), am Mittwoch der dpa.
«Obwohl die Notwendigkeit der Weiterentwicklung bekannt war, hat man
diese zu zögerlich betrieben.» Dabei seien andere Ultraschallmethoden
vorhanden, die als sogenannter Stand der Technik bezeichnet werden.

Seit 1992 werde ein Ultraschallgerät getestet, das von der Firma
Hegenscheidt geliefert worden sei. Es sei in den Hegenscheidt-
Diagnose-Anlagen von Hamburg (1992) und München (1994) eingebaut, die
die ICE-Züge alle paar Tage überprüfen. Anfangs wollte die Bahn nach
Auskunft Diederichs mit der Hegenscheidt-Anlage die Radreifen auch
per Ultraschall in diesem Zeitabstand inspizieren. Sie habe gewußt,
das beim Zugbetrieb Fehler auftreten könnten, die zum Bruch eines
Radreifens führen könnten. «Man hätte wohl kaum Ultraschallanlagen
versucht zu etablieren, wenn nicht die Notwendigkeit dazu bekannt
gewesen sei.»

Der Geschäftsführer der Firma Hegenscheidt, Klaus-Peter Schwarz,
bestätigte auf Anfrage, daß 1992 in Hamburg und 1994 in München
Geräte zur Überprüfung der ICE-Züge aufgebaut worden seien. Diese
Meßgeräte zum Testen der Räder hätten drei Module: Zur
Rundheitsmessung, Profilmessung und die Ultraschallkomponenten zur
Überprüfung der Risse. Die Ultraschallmessung habe sich im Betrieb
aber als unzuverlässig erwiesen, weil Signale von «harmlosen,
oberflächlichen Abbröselungen die Spuren von möglichen Rissen

Daher sei diese Ultraschallmessung in Hamburg Ende 1993
abgeschaltet worden und in München gar nicht erst in die
kontinuierliche Überwachung aufgenommen worden. Das Gerät ist Schwarz
zufolge jedoch ständig weiter getestet worden. «Aus den Ergebnissen
ist ein komplett neues Ultraschall-Modul zur Rißprüfung entstanden,
das in den nächsten drei Wochen in Hamburg getestet werden soll.»

Derzeit diskutieren Experten im online-Forum der Fachzeitschrift
«The e-Journal of Nondestructive-Testing and Ultrasonics» unter
www.ndt.net über bessere Lösungen.

Unter der Internet-Adresse ist unter anderem ein Fachvortrag des
DB-Mitarbeiters Hartmunt Hintze veröffentlicht, der auf Fehler in der
Ultraschallkomponente der Hegenscheidt-Anlage hinweist und
Verbesserungen aufzeigt. «Zwischenzeitlich wurden die technischen
Veränderungen in Hamburg realisiert, und die Erprobung wird
vorbereitet», heißt es darin.
dpa/lni hu yy ek
101727 Jun 98


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