2009 CTs: State Railway of Thailand practice

[PJW]

Earlier in the year I was sent some attempted Control Tables from Thailand.
After a much longer delay than I would have liked, I have finally managed to get the time to give my comments on them.

I think that these should be useful for students from a range of backgrounds, particularly those who are not going to follow the UK Mainline practice as many of my comments reflect on how I think the attempt would be viewed by an examiner only really familiar with the UK.
I think that part of the technique must be for the candidate to be aware where the practices they are following do depart from the default assumption of the UK and think how best to convey that info to the examiner.

Since the files are quite large, I cannot attach all to this same post but I will do so in a succession of subsequent posts.

Here the student has given the layout diagram that they used. I think the idea of marking with a highlighter the relevant route(s) is good; indeed the examiners recommend candidates to do this as often they find that silly slips are made by people in the exam.
Also you can see that other significant signals have been circled and also so have the signal exit numbers in the various route boxes as a means of ensuring that all the routes readig to a particular destination that may need to be considered for opposing route locking etc are correctly identified- another very good idea.

Also whereas I don't exactly understand the exact significance of what is drawn, it does seem that the person has thought about the BT/BU track joint and whether a train on one line is foul of a train passing on the other.

It is clear that the route indications relevant to the signals have been pencilled adjacent to the profile; not sure how this helps but as a candidate if you find it does help you then I suggest you do so.

Particularly when following a non UK mainline practice (and therefore there are things on the layout that are not completely applicable to your railway and therefore you need to interpret into your context), then I certainly do recommend
a) annotating the layout accordingly and writing on it the railway's practice you are following,
b) making it part of your formal answer and hence numbering the sheet with candiate number / module number/ question number,
c) making it clear to the exam invigilators collecting your work that it does actually forms part of it
after all you are told to "show working" and "state assumptions" and for this module this suggestion seems to me to be an effective and time efficient way to do so.

[PJW]

Column style Control Table which differs a bit from UK practice but is generally recognisable. Thailand was never part of the British empire, but certainly a UK influence historically and also more recently for implementing signalling projects.
My memory from the IRSE Convention was that much seemed quite familiar, but there were significant differences; the thing I most remember that when a signal is waiting approach release to be fulfilled, the signal indication ofn the VDU starts flashing red whereas in the UK that same indication would mean that the signal had previously been cleared but had been replaced to danger and the Approach Locking is still timing out.
Hence my presumption before looking carefully at the CTs that much would be the same but there could be some key differences.

Since the files are quite large, I cannot attach all to this same post but will do so in a succession of subsequent posts.

[PJW]

The Point Control Table also differs a bit from the standard UK or IRSE Control Table; I must admit that I think I actually prefer it (perhaps because more like the old Western Region ones!).

I do find the "diagonal" nature of modern UK CTs annotated N>R and R>N with the locking being converse to the calling can be confusing to some; here there are seperate columns for setting Normal and setting Reverse but the locking for whichever direction is all in one separate list. Probably more appropriate to a relay interlocking (or CBI based very much on the same interlocking approach) with one combined "loc function" rather than for SSI using separate "pfm" data for the two separate directions.

There is no specific columns for Time of operation or swingiing overlap controls; neither is there a usefully wide remarks column so if this sort of locking were needed then it would have just to be cross referenced in the table itself and squeezed in the none too generous area at the bottom above the border grid boxes. If using this as a blank in the exam then I would photocpy this format but with the bottom area all covered up- both to make more anonymous and also to give mre area to utilise for adding details of types of locking that do not happily fall into any of the standard boxes

Since the files are quite large, I cannot attach all to this same post but will do so in a succession of subsequent posts.

[PJW]

Attached here are my comments on both the Route and the Point Control Tables.

Overall these look quite good; certainly very neatly presented and almost totally free of careless slips (# see below for one!) so only a small rate of "random" error.
However there are quite a few things that look like "systematic" errors where the same "mistake" is likely to happen whenever similar circumstances apply.
Actually though, not all of these are really wrong, as I am judging against a UK understanding; some may well actually be right accrording to SRT practice. Hence I have tried to indicate in the comments those things that I believe -
a) are definite errors,
b) are possible errors,
c) might be seen as errors by the examiners unless the candidate makes it clear that their practices are subtly different from UK mainline.

Hence I have concentrated more on the generics of CT presentation and practice, rather than aiming to do a 100% of every entry. There are other attempts at these CTs including
1. a good one presented on the IRSE's format CT blanks
and
2. another detailed one which is presented on blanks similar to 11202 issue 4
which can be used to compare your CT entries for the specific routes and points.

#
I note that the route from 371 which was requested was 371D but the route that was undertaken was actually 371A (and seems to have been changed in the naming at the left but not the right of the CT). Since I am only really looking at for generic presentation I have ignored this discrepency.