211 Points Control Table

[interesting_signal]

211 points control table attached.

[PJW]

211 points control table attached.

Here it is, with added comments!
As you realised, the thing that the examiners were really testing you for on this one was: how you'd cope with the two point numbers associated with the single slip. You didn't know quite how to deal with it but at least you showed you were aware.
Other than this I think a random eror of oversight which caused you to miss a few routes and what I think is a misunderstanding re where it is appropriate to time a train to a stand and release its overlap.

Certainly the better of the attempts.However Merlin was correct that these would be contenders for auto-normalisation or at very least an alarm to signaller if left reverse after passage of a train.
Also you need to think re what to do re Track Circuit Interrupters etc; I'd recommend covering this by a general note on a cover sheet or otherwise you need to remember each and every time that you use EL track on any of your CTs that it incorporates the TCI at 211A. One note could cover this and also the one at 202A dropping BF track.

[interesting_signal]

Thanks for the feedback. Yes, I missed the 142A routes as I was far too focused on the B route after doing the route CTs, so it was an oversight. Must not do that in the exam!

I included the ES track in the release of the overlap as I thought the train could possibly occupy part of that track too, in case the driver stopped before getting right up to the signal. Was thinking it was similar to train stopping anywhere on DB or DC track when signalled onto the Up Loop. I can see now that there's no reason for the train to stop before getting to 142 signal (no platform).

A few questions:
Are the extra brackets marked on necessary? Also is it acceptable to use the same type of brackets, i.e () throughout, or is it standard practice to use the different types?

I was going to ask under which column should I have put 212R, as that's what I struggled with, but have now seen how Merlin showed it. I would have only put it against 211N to R though, as when 212 can be N or R when 211 N. Is that right?

Re the point to point locking, I had read about this in the notes, but wasn't quite sure about it. I have a better understanding of it now, but I have to ask why is point to point locking is not current, but pseudo point to point is?

I have taken on board the comments re auto normalisation of the points/alarm to signaller, and the TCIs.

Thanks again for your help. I've learned a lot already!

[PJW]

Thanks for the feedback. Yes, I missed the 142A routes as I was far too focused on the B route after doing the route CTs, so it was an oversight. Must not do that in the exam!

I included the ES track in the release of the overlap as I thought the train could possibly occupy part of that track too, in case the driver stopped before getting right up to the signal. Was thinking it was similar to train stopping anywhere on DB or DC track when signalled onto the Up Loop. I can see now that there's no reason for the train to stop before getting to 142 signal (no platform).

A few questions:
Are the extra brackets marked on necessary? Also is it acceptable to use the same type of brackets, i.e () throughout, or is it standard practice to use the different types?

I was going to ask under which column should I have put 212R, as that's what I struggled with, but have now seen how Merlin showed it. I would have only put it against 211N to R though, as when 212 can be N or R when 211 N. Is that right?

Re the point to point locking, I had read about this in the notes, but wasn't quite sure about it. I have a better understanding of it now, but I have to ask why is point to point locking is not current, but pseudo point to point is?

I have taken on board the comments re auto normalisation of the points/alarm to signaller, and the TCIs.

Thanks again for your help. I've learned a lot already!

ES Track. If you believe that there is a chance that a long train which stopped at a signal to be tailing back onto the tack before, then you are PERFECTLY RIGHT that the route locking on that track must be bypassed; however the TIMING should only take place on the final exit track [the exception to this is in stations where a train may legitimately stop anywhere along the platform length]. Looking again at your entry I find that I also failed to correct something else relevant that ,may also throw light onto yur misunderstanding.
For situations where you consider ER to be as long as the longest train, entry should be:
146(M): [ES, (ER or ER occ for 45sec)]
For situations where you believe that a train could tail back:
146(M): [(ES, ER or ER occ for 45sec)]
The first says that ER occupied for time only bypasses the route locking on ER, the second that ER occupied for time bypasses the route locking on ES as well. Note that NEITHER bypasses the requirement to have 146(M) route normal; the signaller must have cancelled the route (or long-track TORR provided).

Arguably I have used more brackets above than LOGICALLY necessary, but I do think it makes things CLEARER and I would use them particularly where an entry spans various control table columns (i.e. for any sectional release route locking where there is an "occupied for time" element.

I didn't pick you up on it as a minor issue, but you included EL; i.e. overlap route locking. Tends just to be a practice with SSI, not RRI; even for SSI presentation I would not include here, since EL is a deadlocking track (in the 2nd column) so this entry adds nothing and is therefore logically superfluous.

Think I have probably answered question on brackets- you do need to clarify which route llocking is being bypassed by the "or" condition- without any brackets then you are effectively saying the whole lot. Since we are not computers then it is far easier for the writer and reader to "pair" brackets together if different types are used; it is conventional that the inner brackets are (xxx) and if you need to nest then use: [yyy or (xxx)] and if you then need a further level then use: {zzz [yyy or (xxx)]} A bit similar to Excel's use of colours when complaining about "unmatched brackets" in a formula.

Yes regard 212 as the "lead point"; 211 is "shy" and will only go Reverse if 212 is already Reverse. Similarly 212 is like a protective parent and always ensures that 211 is safely back Normal before it itself is prepeared to normalise. Hence it is on 211's CT that we state the requirement of 212R and on 212's CT that we state the requirement of 211N.

I did recognise that I needed to explain the SIGNALLING REASON- indeed that is why I logged on now to do so when I found you had beaten me to it with your post. "Point-to-point" in any of its forms is only a MEANS TO AN END. Basically any moves on the Up Main or Down main require TRAPPING from the sidings and therefore need 211 to be Normal- so they must prove set, locked and detected at aspec level and therefore their route level must do the calling (after having checked for availability of course). This is nothing to do with there being a single slip, other than the fact that a train on the Down Main would generally get all the FLANK that it needs by virtue of 212A (which comes about automatically by calling 212B that is "in line of route" due to the numbering as acrossover); however 211 provides a "sneak" way of getting around 212A and therefore must also be called to give FLANK (and in this particular case being siding exit this is actually TRAPPING). This is the REASON for calling. It so happens that "point-to-point", which in mechanicalling lever locking days was a convenient way of simplifying locking, is an easy way of "seeing" on the layout where it might be needed: two point ends within the same track circuit is usually a "give away". Not all point-to-point is about FLANK but most of it is; "pseudo point-to-point" means just do the calling that "point-to-point" would have done; 80% of the time it is "giving you something" and the remaining 20% of the time it is "doing no harm"- hence "just do it" at route level. The aspect level however should only prove detection for the 80%, to avoid the disadvantage of faulty point detection holding more signals to danger than strictly necessary which was one of the disadvatages (Question: can you think of any others?) of full point-to-point.

Asking questions like these proves to me that you are definitely thinking; this is certainly the way to learn.

[merlin89]

I completely mucked up that CT up by only focusing on 2 routes over the points what a ridiculous error. I can blame my wife ( can't I ) for interrupting me during this. I even made a note to myself from the last CT for P203 that I had missed obvious routes. Well lesson well and truly learned will try to be more vigilant on the 2005 layout.