Report on railway accident with freight car set that rolled uncontrolledly from Alnabru to Sydhavna on 24 March 2010

The accident was triggered by a misunderstanding between the local
traffic controller and the shunter about which shunting route to set,
and the result was that the freight car set started rolling from an
arrival track (A track) at Alnabru. When the shunter added an extra
freight car to the freight car set, the local traffic controller was
convinced that the freight car set was being shunted for loading.

The result of this was that the local traffic controller released the
mechanical brake that held the freight car set in place on the A track.
The shunter had not intended to move the freight car set and had
uncoupled the shunting engine.

There were no shared mental models, standard phrases or
readback-hearback systems in place to prevent misunderstandings of
communication between the local traffic controller and shunting
personnel at Alnabru. Furthermore, two provisions which could
potentially have stopped that particular chain of events were 'dormant'
and not known to the operating personnel.

When it became clear that the freight car set had started rolling and
was not coupled to a locomotive, it had already moved to track G4. It
was not possible to stop the freight car set by setting a diversion
route before it left Alnabru. Nor were there any barriers on the freight
train track between Alnabru and Loenga/Sydhavna which could stop the
freight car set in a controlled way. The accident reflects a breach of
the ‘no single point of failure’ principle which dictates that railway
operations shall be planned, organised and performed in such a way that a
single failure does not lead to loss of human life or serious personal
injury.

In the AIBN's view, the basic premise that allowed the accident to
happen was the fact that Alnabru was being used in a manner for which it
was not originally intended.This was a consequence of structural
changes and increased rail freight traffic, combined with a lack of
remodelling and development work on the infrastructure to reflect this
development.

A focus on efficiency and productivity on worn-out, outdated
infrastructure, and an insufficient focus on updating safe work
practices had reduced safety margins. Political priorities and the
NNRA's own prioritising of freight traffic had played their part in this
lack of alteration or development.

The investigation showed that both the NNRA and CargoNet AS have
consistently failed to handle safety-critical information in a
systematic way. There was not enough of a culture of reporting
incidents, governing documents were inadequately distributed and
implemented, risk assessments were fragmented and inadequate, and the
system for collecting and handling safety-critical information from the
operational parts of the organisations was deficient. The result of this
was that, until the time of the accident, the NNRA and CargoNet AS were
both unaware that Alnabru had fundamental faults and deficiencies in
terms of operational and technical safety barriers.

The NNRA had not adequately followed up its responsibilities as
Principal Enterprise for infrastructure management, for instance through
carrying our overall risk assessments. In a complex system like
Alnabru, it is especially important that all the organisations involved
work together to set up barriers against single failures. This does not
seem to have been properly addressed. Alnabru lacked an overall safety
management system which would pick up the risks that were a consequence
of the many changes that had taken place over time.

The AIBN's investigation has shown that Alnabru does not seem to have
been sufficiently 'seen' by the Norwegian Railway Authority (NRA). Even
if the responsibility for safety lies with the railway undertakings,
the AIBN would nevertheless like to see the supervisory authority
playing a more proactive role in overseeing how the undertakings address
this responsibility. This is particularly important as regards control of the risk of major accidents in complex areas.