NETWORK RAIL
REPORT TO SHREWSBURY ABERYSTWYTH RAILWAY LIAISON COMMITTEE
Lee Green, Network Rail Manager, Wales Region.
October 2011
The story over recent months
is clearly dominated by the commissioning of the ERTMS signalling system and the
subsequent reliability issues. This is very much a mixed bag of positive and
negative deliverables. It has to be acknowledged that the passengers on the
Route have not received the levels of service reliability that they should be
getting.
The details of this variability is as follows:
The system reliability has been extremely mixed. From an "on- train" fitment
perspective the system has shown some really good and consistent levels of
reliability. In many cases, this has surpassed our estimated failure rates.
The bulk of the system integrity, system interface issue have also been very
robust.
The main element of performance and reliability failures are based on FTN
reliability and software operation issues.
The FTN system is utilised to support the indication circuits for a total of 96
axle counters. These have proven to be highly reliable both for the 12 months
before the commissioning, when they were in a ghost mode and. Following
commissioning. This is with one major exception. A set of 5 axle counters at
Welshpool which have suffered a series of repeat failures.
This failure first occurred on commissioning but then self cleared and remained
static for 9 weeks before a series of catastrophic failures.
Although we had always picked up error codes on these particular assets, these
did not materialise into a failure.
When the axle counter data deteriorated into a real problem the monitoring
equipment at both Machynlleth and Stoke Tech were unable to identify the core
reason for the failure.
The action followed was then to bring in support teams from the Telecomms
department, Alcatel and Thalis. Even with this support it took a further 3 weeks
of intensive destructive testing to find the fault.
The eventual problem was not fully isolated to a single problem and was a series
of small but contributory faults on the FTN/data interface infrastructure.
Many lessons have been taken from this failure and National initiatives put in
place.
For the last 4 weeks the system integrity and performance has been very good,
with the consequence that performance for the route has risen significantly
The other key failures have been associated with Operational issues. In simple
terms the system does not allow various activities, route settings, splitting of
units etc. The current system data software controls are too restrictive causing
the system to "lock out" based on an incorrect sequence.
The fix has been a series of conceptual software designs that control any risks
with he movement authority but without the over controlled restrictions.
These changes take several months to develop and implement due to the nature of
change and the detailed system testing that has to be done.
All upgrades will be completed before January 2012.
Other issues and planned works on the Cambrian include the following:.
Week 30 sees a significant blockade between Tywyn and Harlec.
The works taking place are:
Concrete sleeper relay at Sandilands.
Repairs to Barmouth Bridge.
Large scale re-railing and re-sleepering at Harlec cliff. This includes over
1000 sleepers and 296x60ft rails.
We are also carrying out a significant de-veg programme on days within the
blockade and at night in additional possessions north of Harlec.
Two other bridge renewals due to be delivered at Dovey Junction and the Bog have
been put back awaiting clearance reference to Environmental issues with the
rivers.
From Week 42 onwards sees the most significant works on the Cambrian track
asset.
10KM of steel sleeper relays are being delivered over a 10 week programme
between Sutton Bridge and Welshpool.
This is a significant investment in the route and will provide an excellent and
sustainable asset along this section. Where possible any speed increases are
being designed into the track geometry.