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Maintenance Meetings
The meeting as described here give an insight into the planning that takes
place with regards to track renewals and maintenance.
1.0 PPM
This is known as a Periodic engineering Possessions Meeting (PPM).
This is held once a month between Networ Rail and the current maintainer for the zone/area.
The idea of the meeting is to discuss the type of possessions planned for the following four
weeks. A possesion is the term used for stopping trains so that work can be carried out.
There are two main types of possessions:
Disruptive possession - this is where train services are delayed or cancelled due to a
possession.
Non-disruptive possession - this is where no services are delayed or cancelled due to the
possession
In the meeting, as possessions are discussed, the rules of the route are referred to
all the time. This is a large document that indicates the times when work can be carried out
on the tracks without disruption to train services. So, therefore, the reason for referring
to the rules of the route was to see if possessions clash or conform to the times indicated.
To understand the reasoning between train paths and engineering works, it is best to look at
an example.
Let us consider a planned posession. Looking at the diagram below gives a good indication
to the particulars of this case. Due to the
possession, there would only be one line open; the down slow (DS). Most of the work is to
be carried out on one side of the set of points.
Therefore would
it not be possible to change the limits of the possession and then run trains on the up
fast (UF) and onto the up slow (US)? These type of questions
and issues are discussed in a PPM meeting.
Possession planning conflict
Since all possessions and engineering work is planned months in advance, this meeting is
the last opportunity to find any conflicts between train movements and engineering works.
Within these six months, other contractors may come forward and request permission to make
use of planned possessions for other work. At this meeting it is decided whether the request
for other works can be granted or not. If we take another example, this can be clarified
further.
At a PPM meeting, some Train Protection Warning System (TPWS) work is declined because
this would clash with Overhead Line work. The contractor installing the TPWS has requested to be
allowed on site at a certain possession. Due to safety and planning reasons, they may be declined.
2.0 PDR
This is a Plan, Do, Review (PDR) meeting. This meeting is held between the Network Rail
and the maintainer. The items
for discussion are any problems in the area, how they can be rectified and if there are any
plans for the future. This is mainly maintenance orientated but also includes how trains and
services are, or can be, effected.
Looking at some of causes of train delays in the period (a period basically being one month)
helps to identify possible solutions as to how minutes of delay can be reduced. For example,
dry switches can cause many delays; this being because points will not operate if the slides
are dry.
The main objective of the meeting is to allocate actions to the necessary people, for the
applicable jobs or tasks.
3.0 Strategy Planning
A strategy planing meeting is held between different departments within Network Rail.
For example, a strategy planning meeting may be held between signalling Design and
Construction, and the maintainer.
The meeting is
concerning the Permanent way works in Doncaster.
There was a large Switch & Crossing (S&C) renewal being planned there, and the aim of the meeting
was to account for every possibility. People from Doncaster signal box were also
present to ensure that all predicted train paths were viable.
Several aspects were discussed in this meeting.
Corus wanted to do some work while the renewal was taking place. They wanted to continue
building a bridge over the railway, but since they would be using cranes, they were declined.
This is for safety reasons. People would be below.
Other aspects that were discussed included the limits of the possession and train movements.
For example, what would happen if the last train out of Doncaster on the Friday night was
running late? Would this interfere with the possession?
Also, would any other possessions on the zone interfere with on track plant movement. Would a
tamper coming from Scotland be detained by a possession in York, for example?
Track circuits were also discussed. This is because when a crossing is removed, signals think
that the track circuit is occupied and the signal would remain on red. Re-wiring this so that
the signal is green can be done, and is known as 'Frigging'.
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