(14-02-2011, 02:10 AM)onestrangeday Wrote: Hi everyone:
i have question what is 'scheme plan' ? ( I have attached a file as an example). Is that a scheme plan ?? or track plans ? are they different ?
can anyone provide example of a scheme plan & track plan
thanks
william
I think I have the same problem as you have but in reverse; I don't know. Certainly not like any Scheme Plan I have seen before, but yes perhaps it is.
In NR context, the Signalling Plan is a scale diagram (well at least longitudinally, it is not normally to scale at right angles to the tracks to avoid things getting too squashed and confusing) which depicts all the signal, points, train detection sections, traction power isolation breaks etc. Further it includes route boxes that define which signals read to which destination, what route indicator is shown to the driver, whether the signal can clear immediately or is approach released etc. Fundamentally it depicts the signalling as relevant to a driver, signaller etc but does not necessarily show all the level of technical detail.
Actually there is now a tendendency to show more and more including things like access points to the railway which to my mind adds clutter and detracts from main purpose- I'd restrict this sort of detail to the track plan. This latter is the diagram one would need to look at to see depicted all items of equipment that are located in a specific area to sclae / with dimensions; the Signalling Plan should be a "zoomed out" view, allowing one to comprehend the primary features included within a much larger area but be able to see the inter-relationship. Thus it is applicable for design such as the Control Tables of the Interlocking being the "logical reality" whereas the Track Plan (which we often call Location Area Plan) is that for the "outside world" and the "physical reality".
A Scheme Plan is just a Signalling Plan for a new project that is being undertaken and has not yet been implemented; once the signalling is commissioned the alterations (generally shown Red for new and Green for Recoveries) on the Scheme Plan (which depicts in black the info taken from the current Signalling Plan as the baseline on which it is being designed and built) are then incorporated into a new version of the Signalling Plan. This plan only ever shows in black because it is the
record of current operational reality of the railway.
On a very major job, the truth is that the new Scheme Plan actually just effectively becomes the replacement Signalling Plan, with the previous version being scrapped; hence there is a tendency sometimes for those always involved in major New Works to regard the Scheme Plan as the Signalling Plan, because it will be it when their job is finished.
I don't understand all symbols on your plan (perhaps you could send a key / legend to them?) but I am guessing that it shows everything trackside. Certainly it looks quite "diagramatic" and so I think its closest analogy would be to what we call a "Signalling Sketch" or more formally a "Signalling Facilities Diagram" that shows, in perhaps a non scale manner, the bare essentials of what will evolve to be the Scheme Plan for a project. Tends to be used in "optioneering phase" rather than part of the formal design. However as I have said earlier, Signalling Plans nowadays have become unwieldly and this is much closer to the essence of what a Scheme Plan used to be.
Do I assume correctly that the symbols included in the "cloud" symbol (e.g. 3036SF) are those new or altered by the current project?
If so, yes I think that I could be persuaded that thi example is a Scheme Plan; however it may perhaps need to be read in conjuction with some separate information in order to define adequately the operational use of the layout [info may be there but I haven't the competence / experience to recognise it!]
