21-02-2011, 10:01 AM
For me, the paper felt generally as if it has the basis for good answer. However, it seems a tad long considering the ~30min timeframe.
Answers 1) and 2) are the same? For me, the likelihood of reversion is not the length of time of commissioning but the level of risk and the implications for not reverting (is a person's life safer due to a few cancelled trains in the morning or no service? - Hatfield suggests the first).
Personally, I would avoid the words like feel (answer 5). They do not line up well with competence and the precision required within the rail discipline.
Answer six should clarify that competent refers to someone other than the designer who has suitable competence (training, experience, certification) to make an engineering decision. The designer will be involved due to the raising of a test log!
Answer seven, all errors can have a significant impact. The hazard and likelihood (i.e. risk) need to be addresses and the actions taken based upon that analysis. Yellowbook deals with risk assessment and is worth a read. Answer eight discusses communication but if the risk/error were that severe, then it is probable that all relevant parties would be involved in the risk analysis anyhow and coming to a mutual agreement about the path to take.
For example, what are the effects of changing one core on forty thousand relays that form an interlocking? What are the hazards? Can one wrong contact cause a WSF? Would a TIC hand back the railway without fully testing the effects of a site-based mark-up?
For answer eight, think about the risks of hand signallers versus a SIL4 application? Also, the location makes a significant impact. Hand-signllers controlling a clipped crossover with signals that cannot clear for a straight line move against handsignllers at Clapham controlling a crossover!
Final thing. Don't forget, an early issue can screw the programme too! If a commissioning is tight, a simple change can generate significant levels of testing. Again, that would be a consideration to whether the work should be abolished (easier if it is an early minor stage) or whether some resourse reallocation, redesign and the viability (risk versus time versus cost versus implications etc).
Overall, the answer makes sense and deals with some of the issues. A few changes of terminology and clarifications would improve what is a solid answer.
Jerry
Answers 1) and 2) are the same? For me, the likelihood of reversion is not the length of time of commissioning but the level of risk and the implications for not reverting (is a person's life safer due to a few cancelled trains in the morning or no service? - Hatfield suggests the first).
Personally, I would avoid the words like feel (answer 5). They do not line up well with competence and the precision required within the rail discipline.
Answer six should clarify that competent refers to someone other than the designer who has suitable competence (training, experience, certification) to make an engineering decision. The designer will be involved due to the raising of a test log!
Answer seven, all errors can have a significant impact. The hazard and likelihood (i.e. risk) need to be addresses and the actions taken based upon that analysis. Yellowbook deals with risk assessment and is worth a read. Answer eight discusses communication but if the risk/error were that severe, then it is probable that all relevant parties would be involved in the risk analysis anyhow and coming to a mutual agreement about the path to take.
For example, what are the effects of changing one core on forty thousand relays that form an interlocking? What are the hazards? Can one wrong contact cause a WSF? Would a TIC hand back the railway without fully testing the effects of a site-based mark-up?
For answer eight, think about the risks of hand signallers versus a SIL4 application? Also, the location makes a significant impact. Hand-signllers controlling a clipped crossover with signals that cannot clear for a straight line move against handsignllers at Clapham controlling a crossover!
Final thing. Don't forget, an early issue can screw the programme too! If a commissioning is tight, a simple change can generate significant levels of testing. Again, that would be a consideration to whether the work should be abolished (easier if it is an early minor stage) or whether some resourse reallocation, redesign and the viability (risk versus time versus cost versus implications etc).
Overall, the answer makes sense and deals with some of the issues. A few changes of terminology and clarifications would improve what is a solid answer.
Jerry
Le coureur