Reply from Office of Rail Regulation dated 14 February 2007

Staines & Windsor Line - Black Potts Bridge at the Jubilee River Weir


Thank you for your letter of 27 October 2006 detailing your concerns
regarding the condition of Black Potts Bridge at the Jubilee River Weir. We
have received the information we requested from Network Rail and are now in
a position to provide you with a full reply. Please accept my apologies for
the delay in providing you with a response.

It may be helpful to explain our role in matters such as this. The Office
of Rail Regulation (ORR) is principally responsible for ensuring that
Network Rail conforms to the requirements of its network licence. Condition
7 of the network licence stipulates that: "the operation and maintenance of
the network" must be secured "in each case in accordance with best practice
and in a timely, efficient and economical manner so as to satisfy the
reasonable requirements of persons providing services relating to railways
and funders in respect of the quality and capability of the network". In
effect, this means that Network Rail is required to ensure that the safe and
efficient operation of the railway is protected. Since 1 April 2006, ORR
has also been the safety regulator for the rail industry, taking over this
responsibility from the Health and Safety Executive (HSE).

In response to your concerns, an ORR (HMRI) inspector visited Black Potts
Bridge on 9 November 2006 to investigate the condition of the bridge. We
also contacted Network Rail who sent their own inspection team to the bridge
in early December 2006. Following the inspections, both parties reported
that they had identified cracks in the brickwork, but found no evidence of
loose brickwork that was in immediate danger of falling away from the
structure. Our Inspector also visited again on 2 February 2007.

Our engineers and inspectors have reviewed recent inspection reports of the
bridge provided by Network Rail, and have questioned Network Rail in some
detail regarding its condition. We consider their responses to be
reasonable and acceptable and we summarise them below for your information:

Flood protection measures: Network Rail consider the measures that the
Environment Agency have put in place to protect the bridge from high
floodwater to be more than adequate to protect and support the structure.

Frost and water damage: Only a small amount of damage would be caused as
frost would normally only effect high or exposed locations. At this
location, especially close to the river, the thermal capacity of the
structure would be sufficient to prevent serious frost damage.

Longitudinal fracture to the arches: This is a common defect in masonry arch
railway bridges. The cracks are caused by transverse shear and torsional
effects of loading on adjacent tracks, generated by passing trains
travelling in opposite directions. They are usually benign. Network Rail
is monitoring the cracks in Black Potts Bridge, both for movement and for
loose brickwork.

Network Rail considers the bridge to be in a reasonable condition with no
immediate cause for concern. We understand that as part of Network Rail's
on-going asset management programme, a further detailed examination of Black
Potts Bridge is already programmed to take place in the early part of 2007.
Given the age and type of structure, this inspection may indicate the need
for minor remedial works of a non-urgent nature, but we are not expecting
this examination to uncover any major defects that will require immediate
attention. We will ask Network Rail to inform us of the outcome in due
course.

We have investigated the condition of Black Potts Bridge within the remit of
this office and we are satisfied with the responses that Network Rail has
provided to our questions. We are satisfied that Network Rail has conducted
their stewardship of this asset in a manner that is compliant with their
obligations under Licence Condition 7. Therefore, we regret that there is
no further action we can take regarding your concerns.

Thank you again for contacting us.