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Surveying
Before any designs can be considered, a site survey has to be carried out. Done by the
designers, a topographical profile of the land has to be determined. This is done by
setting markers out over the land and setting up a sight, set to a datum of zero. The
sight then focuses on the markers and determines weather they are higher or lower than
the datum. The resulting figures indicate the profile of the land.
Once the profile of the land is obtained, the design process can be undertaken. The
survey results are formed in a spreadsheet format and are transferred over to a software
program called MOSS, or nowadays, known as MX Professional. Ordinance survey maps can
nowadays be bought electronically. As a result, the surrounding geography, land, buildings
etc. can be pasted into this software.
I was asked to assist with a site survey, and I thought this would highlight how surveys are
carried out. This was to be a laser sweep of a signal gantry at Hatfield. The outcome would
be a profile of the track and surrounding features. The job was for the purpose of gauging.
It was suspected that the gantry was of a sub standard distance to passing vehicles, i.e. less
than 250 mm.
After a four-hour drive to Hatfield, we met the site safety people at Hatfield station. The
people we met were a site warden, some chain men and some hand signal men.
Once at the place of work, it was found that a contractor was already at work and had a T3
possession. That is, a total blockage of the lines.
As a result of this, we had to see the Engineering Supervisor of the work already in progress
to see if we could enter his green zone. Since the nature of the work already taking place
was quite dangerous, we were denied access to the site. This was because rail grinding was
taking place, and the fact that sparks would be flying everywhere would put us at risk.
I feel that the drive down to Hatfield, the hiring of hand signalmen and the time of myself
and the surveyors was a total waste of resources. All this will have resulted in Corus
having to spend an additional amount of money, all to no avail.
This brings me the opportunity to highlight an idea with regards to possession planning. I
feel that it would be a good idea to set up a national database of planned possessions. The
database would include all types of possessions, weather it is a T3 (full blockage) or a T2
(working between trains). The database would include the nature of the work being carried out,
the company doing the work and the Person In Charge Of the Possession (PICOP). The database
would include long term planning as well as short term planned possessions. The really
beneficial thing about such a database would be that a hotline could be set up to request
information. So, if someone was wanting to go and work somewhere, with one phone call to
the operator, the person could find out if a possession was already booked for that area
and if not, book one through the appropriate channels.
It is important to realise that this incident was not a one off. According to several
engineers and surveyors, this happens quite a lot.
Implementing a system like this may be quite expensive initially, but if it can prevent
things such as being turned away from site when it is found that work is already being
carried out, then I feel that implementation would be good for the railways.
A couple of days with the designers ensured I grasped some understanding about the different
kinds of p-way design. Fundamentally, there are two types; horizontal design and vertical
design.
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