Proceedings 2002/2003 - IRSE

WESTERN SECTION 133
The future development needs to have a support
system to allow for the safety approvals to be
addressed. It also needs another site where the
track layout and the outside signalling doesn't
change. This will then allow the interlocking to be
fully tested using “Over and Back” methodology.
The best way forward is to build on past experience.
(Attendance 20 members, 8 visitors)
The second meeting took place in the usual venue
of WRSL’s offices in Chippenham, where we were
privileged to be joined by our President Mr Peter
Stanley, who gave us a short talk on the perspective
from the Centre. Mr John Martin and George Dewar,
of Atkins, then presented their paper entitled “North
Staffs Resignalling”. John introduced himself and
George before stating that he would outline the
North Staffs project, then George would introduce
the axle counters which were used and say something
about the safety approval, finishing off with
some of the hurdles they had to jump.
The main reason for renewal was the asset
condition. It had passed beyond its service life. The
project was the centralisation of control on Stoke on
Trent with the resultant closure of seven old signalboxes.
The new signalling covered 120 colour light
signals, 40 ground position light signals, six level
crossings (five CCTV and one AHB), 50 point
machines, seven SSIs 21 axle counters covering 220
sections, 78 locations, 21 REBs 40 miles of cable
route using 435km of cable. The capital cost of using
axle counters in place of track circuits was an
increase of 10%. However, the whole life costs were
considerably less. There are no track circuits anywhere
on the project. The provision of TPWS was
designed into the scheme as an integral part and not
a “bolt on”. There was also an integral condition
monitoring scheme.
North Staffs was commissioned on the 27th May
this year using a 24-day blockade. There were no
stage works at all.
At this point George took over. The axle counters
used were the Alcatel AzLM using digital technology
and the multi-headed system. They were used at
North Staffs because they were at the right point in
their development. This imported additional risk to
the project but the conceptual design and the
safety case used in the North Staffs application was
based on the core system in use on DB and using
the cross acceptance approach to the safety case
approval. Risk assessments of interfaces and the
use of a trial site at Stone in July 2000 using 16 sections
proved to be very useful. To get the necessary
approval, a conceptual safety case, GETS control
system safety case, AzLM reset and restore risk
analysis (for the conditional reset) and the applications
manual were all required. The conditional reset
system was used as only one signalbox – Stoke –
was involved. If the last count was “in”, the system
would not reset, if the last count was “out” it will.
There is also the availability of the "sweeping train"
reset but this was causing a lot if delay to the first
train of the day. Consequently a dedicated “sweeping
train” is now being used.
George then returned to the benefits of using axle
counters – namely reduced delays, fewer SPADs (cat
B), rail contamination is no longer an issue and
reduced EMC problems. The concerns were
addressed by “expert groups” especially convened
to look at the problems which mainly were the reset
and restore requirement and the detection of the rail
integrity. (Attendance 19 members, 6 visitors)
The Christmas paper held in Amey’s office in
Bristol, was the sequel to last year’s paper and was
entitled “Checking the Chieftain”. This again was
presented by John Francis of WRSL. Again the
audience gave rapt attention to John for over two
hours. No divulgence of mis-spent youth in the West
Country this year as the paper was set during John’s
time in central Scotland.
John introduced himself by saying that this
covered the period around 1990 when he was a
signaller in central Scotland at Greenloaning and
Carmuirs signalboxes. He started by way of a few
“props” explaining there particular use during that
period. They were a Stop Order – which allowed the
signaller to get home – and the On Company Service
(OCS) sticker which allowed selected goods to be
conveyed to other parts of the country without
charge!
The paper was delivered with the aid of slides to
which the anecdotal commentary was added.
Greenloaning was one of the first boxes to be
worked by John when he went up there after
returning from Australia.There were various views of
the box in both summer and winter. During the
winter months, ie from November through to March,
the outside toilet – which was “plumbed in” to the
culvert – was of no use as it was frozen up.
From there after a short spell in other boxes
nearby allowing him to work up the signalman class
system, he spent a period south of Edinburgh as a
crossing attendant during the electrification of the
East Coast and the joining up with the West Coast
electrification.
John the returned to central Scotland to the
Carmuirs East and West boxes and Larbert Junction
which together formed a triangle serving Perth,
Edinburgh and the Forth Bridge. There were various
techniques explained which ensured that the
“Chieftain” was stopped at signals whilst the local
“Orange peril” trundled on past right in front of the
“Chieftain” at around 15mph. Nearby was also a golf
course which provided both a short cut home and
entertainment at the expense of the golfers on the
course. The signal layout was explained and how, on
occasions, it was necessary to send trains around
two sides of the triangle to keep them moving when
a problem had occurred.
One o’clock on a Saturday afternoon was a
notable time as the whole area became very quiet as
in the bus station behind Larbert signalbox, all the
machinery was switched off. It was only then that
you realised the high level of background noise that
was present all the other times.
Finally, John showed a few traditional slides from
a slide projector, covering some views of the
different trains and seasons up in that part of