13-09-2012, 05:37 AM
(12-09-2012, 11:43 PM)PJW Wrote: Since it is not long now until the exam,perhaps I should put on my "critical examiner" hat and tell you what I think they would say had this been your exam answer-
1. Don't waste your time writing out the question.
2. Don't use abbreviations such as BD without explaining.
3. Don't quote formulae without explaining their derivation, except when widely known using the common terminology (e.g. Newton's equations of motions)
4. Braking distance calculations- not all are needed so more wasting time. Answers not quoted to reasonable precision-train braking from 160kph is not within tolerance of a few centimetres, neither is it sensible to quote acceleration times in thousandths of a second
5. Not sure what you are calculating when attempting Headway for Stopping Trains- in fact it seems that you don't either.
6. Having decided that 3 aspects cannot achieve non-stop headway, what is the point of calculating the stopping headway for 3 aspects?
Overall haven't been too convincing that you know that you really know what you are doing; there are individual bits which are ok but answer wouldn't score highly.
Sorry if this seems harsh, but best you know this; actually it would not take much to considerably improve
hi PJW,
can you please send your comments in calculations and the purpose of posting is if both 4-aspect and 3-aspect headway is not within the required headway(even we didn't deduct contingency) then what is the solution?
clearly we know each step in the attached file but we did each possible step for searching required headway,
also I wanted to know whether the procedure we followed for solving the headway and breaking calculations is wrong?
if so please send the correct procedure in your opinion