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Mod7 Study Guide - Chapter 1 activities
#1
Looking at Mod7 for next year but rather out of my depth. Would someone be kind enough to pick holes for me please?

p.s. excuse my handwriting!


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#2
Activity 1.1
For a signalling renewals project identify the engineering activities that would typically be carried out at the project concept and definition phase. Identify the purpose of the outline project specification.


Reasonable, but perhaps you should have focussed first on what would drive the need for a renewals project.
In essence there is presumably already a current problem with asset performance or the trend is such that there is expected to be. Clearly there needs to be a business case that in the long term it will be cheaper to renew a certain portion of the signalling system than carry on operating and maintaining the existing one with spot, like-for-like, replacements of separate components. Therefore calculating the current and future costs (and this means equipment and labour costs for maintenance, as well as the expense caused by failures in train delay compensation etc) to know how much budget is available to spend must be the starting place.

Then there is a lot of optioneering to do to decide the relative costs / benefits of different degrees of scope; to use your example of needing to eliminate obsolete point machines then to try to decide
a) just to replace them,
b) to replace them, the supplementary detectors, the cabling to the locs,
c) to tie in with P'Way renewals and relay the whole junction area,
d) to renew the lineside location as well as the point operating equipment
e) to replace all the lineside equipment and cabling in the whole area in broadly like-for-like form,
f) to replace the whole signalling in the area in modern form
etc


Activity 1.2
The V life-cycle enables a series of baselines to be established under configuration control as the product development progresses. Identify the points at which these baselines should be established.

Yes you need to do some reading relating to life-cycles! However in essence the project starts at the top left of the "V" with the high level requirements, descends down as the project definition is done in increasing levels of detail during the feasibility, optioneering, system architecture, specific detailed design for individual elements. Then progresses up the righthand side of the "V" as individual bits re made and checked first individually and then joined together as sub-systems and these then integrated with each other to achieve the whole complete system.
Model really comes from software development and whereas can be applicable to more conventional railway signalling, it isn't a perfect match. A reasonable example is that from a certain baseline consisting of things such as Signalling Scheme Plan, Location Area Plan, TFM schematics and interface specifications, ID lists etc. then various workstreams can progress in parallel: location design, Smartlock VIXL data, Test Environment, Support System, IECC data etc. Each can be tested to a certain extent "by itself" but the off-site Principles testers need a consistent seto f VIXL data, Test Environment data, Support System data and once this combination has been proved to work "well enough" then those versions can be used to undertake site through testing even whilst there are further passes of the data being subject to more off-site testing to resolve Test Log issues etc.
If you think what goes on a conventional SSI CISR or a Smartlock release build, then you have got the general idea of a baseline. However it isn't only software; the basic concept is equally applicable to all design so therefore you shouldn't start designing Control Tables before there is a fully signed off Signalling Scheme Plan and all the signals sighting forms and axle counter siting forms etc are made "Approved For Construction" , shouldn't start writing data / designing circuits before there is a fully signed off set of Control Tables and so forth.
[Whether in the current NR project environment this is actually practicable is at least debatable, but certainly when this rigidity is not observed (non-sequential working, parallel design) then the chances of mistakes being made are certainly certainly increased- dare I say: "Barton Lane", "JML axle counter"........ ]
PJW
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#3
Activity 1.2
This is not really about V life-cycle then, but is more about detail design?

(Slough: finished designing CTs, and Data is being checked and the scheme plan is not yet correct, any sighting/siting we have is draft - you have to wonder what risk to commissioning)
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