23-09-2019, 10:14 AM
Morning,
Good to see the table, your answers for part a) look correct. Another thing to add might be a primer for the Newtonian calcs for the examiner's benefit.
Your part b) HT3 and HT4 calcs use the headway minimum braking distance rather than the maximum PSR 160km/h braking distance. I calculated 85 seconds for 3 aspect and 69 seconds for 4 aspect using a braking distance of 1235m.
The calculation principles and diagrams are good as ever so well done.
The poster above offers good advice about calculating part c after some layout details.
The best way (in my view) to reduce your calculation time is just practice and knowing your answer structure.
With regard to the design rules, standard practice seems to be stating high level assumptions on the paper (for example- "assume all train detection is axle counters, treadles not shown", etc). If you were applying ETCS principles which require long explanation on the paper this may be a big constraint in the exam. You could denote specific areas requiring clarification or practices used on the paper next to the effected area with a brief note.
Good to see the table, your answers for part a) look correct. Another thing to add might be a primer for the Newtonian calcs for the examiner's benefit.
Your part b) HT3 and HT4 calcs use the headway minimum braking distance rather than the maximum PSR 160km/h braking distance. I calculated 85 seconds for 3 aspect and 69 seconds for 4 aspect using a braking distance of 1235m.
The calculation principles and diagrams are good as ever so well done.
The poster above offers good advice about calculating part c after some layout details.
The best way (in my view) to reduce your calculation time is just practice and knowing your answer structure.
With regard to the design rules, standard practice seems to be stating high level assumptions on the paper (for example- "assume all train detection is axle counters, treadles not shown", etc). If you were applying ETCS principles which require long explanation on the paper this may be a big constraint in the exam. You could denote specific areas requiring clarification or practices used on the paper next to the effected area with a brief note.