03-09-2014, 06:19 AM
I think that what you have written here is much better and certainly sufficient; they weren't asking for a full description of any particular system but I do think it is best to focus on something solid as an example.
What you wrote for d) in this posy seems at the correct level- enough to explain concept but not too much detail for which you'd gain no further marks
What you wrote for d) in this posy seems at the correct level- enough to explain concept but not too much detail for which you'd gain no further marks
(02-09-2014, 10:03 PM)greatnessjason Wrote: Thanks PJW for the very detailed comments.
a) I agree that I should have used "target speed" or "current speed" to word this rather than "speed profile"
b) i think what I meant to say was that it relied on drivers following the rulebook procedures as to what speed to drive the train on at a particular aspect displayed by the signal
d) Basically the 3-aspect speed signalling "arms" is analogous to semaphore signalling arms. The a-arm means "normal speed" and b-arm means "medium speed" while c-light is for permissive moves. For examples a Red over yellow with c-light extinguished means to the driver a "medium speed move with next signal at stop". A Green over Red with c-light extinguised means "Full line speed permitted through straight route with next signal at proceed". c-light is only permitted to show a yellow aspect (I believe this would be equivalent to a PL signal in UK signalling) when both a-arm and b-arm are at red.
I was contemplating to explain the whole rules regarding the aspects displayed on the Victorian Speed Signalling principles (would something like the above suffice?) however I wasn't sure whether marks would be allocated if I did went into the whole discourse - as in, would the description like the above equate to 1 mark awarded?
PJW