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In UK terms I would not expect MCB-CCTV to be considered an Automatic crossing because the signaller has to insect the crossing and give crossing clear before the protecting signals can be cleared. This would be the case even if fitted with auto-lower and auto-raise.
A full barrier automatic crossing would be an MCB-OD where the object detectors prove crossing clear.

I guess you'd have to assume that the crossing was there before the school or the AHB is not appropriate.

Without seeing the question, one additional feature might be to repeat the road warning lights as miniatures at the pavement, eye level for school kids?
It seems, for part on you could have said AHB but noted the speed and location were higher risks than "normal". Part two, add OD and possible a pedestrian bridge? Some assumptions were made that the school kids used the LX. It could be the entrance is not that close and all/most actually go the other way up the road. If the foot fall is low, is the risk actually high?

Argument should consider cost, i.e. reasonable cost first (and providing what the examiner is asking for - an auto LX), then add to it (cost, complexity etc) for the latter parts of the question.
Maybe they were looking for MCB-OD in the first place ?
Then how can OD be improved? What else can be done to reduce the risk? How could Part 2 then be answered?

The exams wants to show understanding of principals. To select the most costly and complex solution first off shows little knowledge and screws the rest of the question. An AHB could be selected based on a detailed risk assessment and initially selected by stating any assumptions to support its selection.

Don't assume a school or a higher line speed is a high risk. With OD, what is the level crossing has an excessive hump in the middle? Then there is the additional implementation, maintenance costs, additional spares... all when an AHB may have been perfectly acceptable with additional measures.
Dorothy mention, additional features might be " to repeat the road warning lights as miniatures at the pavement, eye level for school kids". This could be a MCB-OD enhancement. I suppose my initial question was "can the wording "automatic level crossing system" and "uses barriers which cover half the road width" be interpreted as being anything other than a AHB" even with the correct assumptions.

I believe the principle's can be demonstrated with the correct assumptions. I suppose what I am asking in a round about way is. Can we accept it could/might/possible be a CCTV crossing with the upgraded safety feature options to MCB-OD or other. Here in Ireland we have eliminated all AHB as they are not now considered an acceptable risk going forward. The cost in this case wouldn't be a factor to consider unless there was an alternative option to putting a crossing in, such as a bridge or road diversion for example. Then the cost of this would be a consideration. However I appreciate that AHB's still play a big part in the UK.

The question also states busy suburban, so we don't just have the school and speed to consider. From material I have read schools and suburban were reasons not to consider AHB's however with the correct assumptions highlighted by all this could be made to work. Dorothy suggested we could assume that the AHB was there first before the school and possible area being defined as suburban.
Jerry is right to highlight assumptions. If the school is at the edge of a suburban area and very little school traffic goes across the crossing then risk might be acceptable. If we were to imagine that situation, do we need to take into account that the suburb may expand with housing built on the other side of the crossing making greater road/pedestrian traffic predictable.
Note that I refer to UK mainline practices as that is my experience - so I am working on a project at the moment that will upgrade a number of AHBs to MCB-OD or MCB CCTV. My experience says a CCTV or OD crossing is always full barrier and therefore not what is intended in the first part of the question.
Referring to your experience you could be thinking about what was done to eliminate AHBs.

Upgrade options are therefore MCB-CCTV. MCB-OD, bridge, closure+diversion. plus what other mitigations of lower cost you can think of.
For full barrier crossings I wouldn't have thought repeaters of the crossing lights would make much difference to risk. Adding them on a half barrier crossing might help reduce pedestrian misuse by negligence (but not deliberate misuse).
(10-10-2017, 08:12 AM)dorothy.pipet Wrote: [ -> ]Peter, can anyone ask an Exam Facillitator for a copy of the papers then?

I have not had sight of the facilitator notes this year as I have taken a secondment in Australia at the moment so did not run the exam centre. However, last (and previous years) it was clear that the facilitator had to collect question papers and to tell candidates that they could ask for them the day afyer the exam.

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