2001 Layout Route CT's

[PJW]

Hi,
I have just looked in to the routes and found the below items.

I was rather surprised re the number of routes and therefore checked back to the question paper: certainly it says 107B, 113, 305B so the examiners seemed to have been kind that year in terms of quantity; no doubt they were hoping that quality would be improved as a result. In fact it does seem quite an easy layout compared to many others.

Blank CT
I think this works ok, although I'd be tempted to make the route calling level a little deeper; you could probably sacrifice two divisions from the Aspect Displayed row. If you get a route with lots of opposing route locking then that extra space at the top level would be invaluable.

I suppose it would be a bit messy and time consuming but if you typex-ed over the division marks that you are not utilising on the top border line, you could then save some space at the top by writing your text higher up where these currently are. Otherwise I suppose you could always use the Notes are at the bottom as an overflow which you could arrow up to the relevant area.

You are probably wise to list the individual point ends that are detected for the time/space that it takes to do so; hence you don't need to write "all ends" in the box heading- this will save you a little space in what is squashed.

I'd loose the vertical divisions which you have shown within the Comprehensive A/L presentation- the first isn't needed at all and I think you can forgo the second (under "or" as there will be enough separation to be clear) and thus you are left with the 3 methods which column heading shows.


Route 107B(M)
This was pretty good including the swinging overlap. I think that I might wondered about setting 206N for the overlap over 205R, but that is a frill.
Again I wouldn't have written the aspect level re the point conditions in the swinging overlap quite like that (I'd have had combined entry spanning the first 3 columns linked by dashes), but the presentation was clear and, apart from quibbles, correct so stick with it.

You showed G up to 111@G; nothing wrong with this but not supported by the route box supplied. Since the only route for which 111 can show Green is into platform 1, then it is not going to be a usual move at all as 107A would be used instead. In the mindset of RRI then the "better aspect" would not have been provided because it cost to provide it; in the mind set of SSI it comes for free (and indeed would be more trouble to prevent it!). Hence I agree with your CT (you didn't define anywhere your standards but I am sure that you are "SSI minded" and the separate A.L for each class of route from a signal reinforces that)- however that is just the thing to note in the remarks column to show it is conscious decision, not a failure to read the route box information.

Comprehensive A/L lookback. Since 107B(M) cannot clear unless AF occupied, then this route would be "when cleared". The entry you showed would however be appropriate for 107A(M).

Route 305B(S)
You missed some opposing locking from 310B(S) and 110A(M) for some reason; I suspect that you did 108 and then looked further to the right and got yourself sidetracked. Always worth reviewing the entries when you think you have them all and then just looking for the "parallel" signals to any that you have listed, just to make sure that you have excluded them for good reason, not as oversight.

Jenni is correct when says:
In the Opposing locking, Route 108B(M) and B(W) does not require BH Track clear as it is the Berthing Track for signal 305
the route locking after 108 etc should be only to BJ, not BH

Simiarly Jenni is correct when says:
The aspect displayed column should be PL alone as the exit is a shunt signal which will not have a Red aspect
Aspect is just PL; it is a GPL not a (S) associated with a main signal!

Route 113A(M):
113A(W) require locking where 209A(W) is shown by mistake. 209 is the point in the route.

109A© should be locked with track circuits clear as per Huddersfield locking.

You missed out track circuit 'BP' which is in the route in Track Circuit clear column. The same is the case in the TC sequence. It should be: AN clear, BP Occ after AN occ, BP occ.

Indeed I think you must have had a brainstorm and wrote 209 ather than 113; also you meant 312B(S) rather than 312A(S). The route boxes for the Up have been done in an Eastern Region (=upside down) manner that us Southerners just think is done to confuse.......Keep your wits about you in the exam.

Yes to modern standard all routes from the platform exit signal would be locked whilst there was a call-on (or sometimes also a shunt) route in progress from the platform admission signal.
I'd represent this is a simplified form as:
Route Normal Maintained by Tracks
109A(C ) AJ, AK
111A(C ) DE, BJ, BK, AK
305A(S ) BJ, BK, AK
The requirement is so that drivers receiving a permissive passenger PL aspect don't get used to finding the platform clear by the time they arrive and therefore exercise insufficient caution, until one day they find that they do need to stop their train short of the previous train. If the locking is being provided for a call-on, then many places also impose it foe shunts as well for consistency even though not strictly needed.

Yes you fell for it; ALWAYS look for the track joints and then find the relevant track name; don't just look out for the track names your route passes over.
If you were really clever you might decide that BP over 209R was such a short track that may not be seen as occupied for 2 seconds which could mena that SSI wuldn't achieve TISP; the solution wuld be to use BP and BQ in combination as the "2nd" track in the A/L release.

The other thing that you missed because it was not there is the opposing route locking up to 118. The oplan is deliberately silent regarding what happens at the far end of the single line, but you can't afford to adopt a "out of sight, out of mind" approach. You should have recognised that there would need to be some way of avoiding a head-on collision. There is no reference to working line by token, there is no obvious slot but it appears to be a line worked by TCB. Put a note in the remarks column and postulate a signal 122 and give it route locking on tracks BW, BV, BU, BT, BS.

You noticed the requirement for signal 115 to be off- you probably didn't need your #1 note as the CT reflects anyway, but does no harm

Route 113A(W):

Instead of 113A(M), 209A(M) is shown.
109A© require locking with TC clear.
Missed BP track circuit and the track sequence.
Please correct me if am wrong.
regards,
Jenni.

Yes same issues again. I do wonder why gave you two such similar routes.
You could have mentioned that (W) set by use of separate exit button.
I think that 10s trather short for A/R; I'd have gone for more like 20s
You show that signal only shows best aspect as Y; this time you followed the Route Box whereas SSI practice would have permitted it to show G if signal 115 changedafter 113 had cleared. It doesn't really matter what you do in such circumstances, but try to be consistent