31-08-2014, 07:52 PM
I am afraid that my paid employment workload is very high at present and severely limited the time I have available to respond to things placed on the Forum, so I am having to be selective on what I can comment upon.
My main comments on this layout are:
1. Safety- you failed to put trap points on the Up Freight Branch and the Down Freight branch at junction C.
2. Safety- you had several signals where there was not an appropriate warning to the driver to stop; the first warning must be at least braking distance on the approach. For example with 115 at Red, signal 111 will show YY but it is only 1660m prior; can't see why you [placed 115 where you did.
3. Operability- you failed to provide a way that the freight going from A to B / coming back from B to A can run around via the crossovers at C & D. You did provide a move that after the loco has magically got to the left hand end of its train that it can then push it back onto the Up Main, but the LOS is too close to 112 and so a 400m train won't fit.
4. Operability- it would have been better to place 110 further from the station so that it can have an overlap independent from that beyond 111 so that a train from the branch can run up the Down Main whilst a train entering station D on the Down Main.
5. Operability. Given that 112 is not braking from 106 anyway, it would actually have been better to position closer to the station. Making it a 4 aspect was a mistake because there is plenty of distance for braking from 106 to 104 so an earlier warning is certainly not required. You have placed 114 full braking distance in rear of 112 so 114 should be a 3 aspect as well. To make the short section from 112 to 106 safe, then you simply require that 112 is approach released when 106 at Red. This will have a detrimental effect on achieved headway but your calculations show that there is quite a bit of contingency if signals on their minimum spacing, so should be ok.
6. Operability-
By placing 202 where you have without an overlap clear of 408 points means that the Down Main beyond station D is unusable as soon as the branch train has been signalled to return from station G. Unworkable!
7. Economy-
Don't see reason for providing signal 105.
Don't see any requirement for the permissive moves from 110 / 112 into the various platforms.
8. Economy- TCB isn't the best way of operating a 15km dead end line with only 1 train per hour shuttling Down and Up it. You certainly will not get a track circuit to work ovr a length of approx 13km as you have drawn; if that is what you intend then you should either show in sections of no more than 1km (not very economical!!!) or better declare it to be axle counter train detection. [Indeed there were some other track sections on this layout that were too long to be single track circuits.]
TCB requires full train detection and a signal at the point of reversal (which you did provide - 206, but it shouldn't have been given an overlap). I think some form of One Train Working, perhaps with a train staff would have been sensible and by using reflectorised distant boards then there would be no need for a cable rote and power supply for more than a few hundred metres (for a berth track) on the approach to signal 202 rather than the additional 14km that your solution would require.
There are a few other things that I have noticed and I will tomorrow attach a scan of the layout, but I think the above are the most significant. Overall not too bad but let down particularly by similar things to 1999 attempt-
TRAP POINTS
OVERLAPS LOCKING JUNCTIONS FOR UNACCEPTABLE TIME
NOT REALLY UNDERSTANDING 3 / 4 ASPECT TRANSITIONS
NOT UNDERSTANDING THE OPERATIONAL MOVES ASSOCIATED WITH FREIGHT TRAINS
regards,
PJW
My main comments on this layout are:
1. Safety- you failed to put trap points on the Up Freight Branch and the Down Freight branch at junction C.
2. Safety- you had several signals where there was not an appropriate warning to the driver to stop; the first warning must be at least braking distance on the approach. For example with 115 at Red, signal 111 will show YY but it is only 1660m prior; can't see why you [placed 115 where you did.
3. Operability- you failed to provide a way that the freight going from A to B / coming back from B to A can run around via the crossovers at C & D. You did provide a move that after the loco has magically got to the left hand end of its train that it can then push it back onto the Up Main, but the LOS is too close to 112 and so a 400m train won't fit.
4. Operability- it would have been better to place 110 further from the station so that it can have an overlap independent from that beyond 111 so that a train from the branch can run up the Down Main whilst a train entering station D on the Down Main.
5. Operability. Given that 112 is not braking from 106 anyway, it would actually have been better to position closer to the station. Making it a 4 aspect was a mistake because there is plenty of distance for braking from 106 to 104 so an earlier warning is certainly not required. You have placed 114 full braking distance in rear of 112 so 114 should be a 3 aspect as well. To make the short section from 112 to 106 safe, then you simply require that 112 is approach released when 106 at Red. This will have a detrimental effect on achieved headway but your calculations show that there is quite a bit of contingency if signals on their minimum spacing, so should be ok.
6. Operability-
By placing 202 where you have without an overlap clear of 408 points means that the Down Main beyond station D is unusable as soon as the branch train has been signalled to return from station G. Unworkable!
7. Economy-
Don't see reason for providing signal 105.
Don't see any requirement for the permissive moves from 110 / 112 into the various platforms.
8. Economy- TCB isn't the best way of operating a 15km dead end line with only 1 train per hour shuttling Down and Up it. You certainly will not get a track circuit to work ovr a length of approx 13km as you have drawn; if that is what you intend then you should either show in sections of no more than 1km (not very economical!!!) or better declare it to be axle counter train detection. [Indeed there were some other track sections on this layout that were too long to be single track circuits.]
TCB requires full train detection and a signal at the point of reversal (which you did provide - 206, but it shouldn't have been given an overlap). I think some form of One Train Working, perhaps with a train staff would have been sensible and by using reflectorised distant boards then there would be no need for a cable rote and power supply for more than a few hundred metres (for a berth track) on the approach to signal 202 rather than the additional 14km that your solution would require.
There are a few other things that I have noticed and I will tomorrow attach a scan of the layout, but I think the above are the most significant. Overall not too bad but let down particularly by similar things to 1999 attempt-
TRAP POINTS
OVERLAPS LOCKING JUNCTIONS FOR UNACCEPTABLE TIME
NOT REALLY UNDERSTANDING 3 / 4 ASPECT TRANSITIONS
NOT UNDERSTANDING THE OPERATIONAL MOVES ASSOCIATED WITH FREIGHT TRAINS
regards,
PJW
(26-08-2014, 07:56 PM)PJW Wrote: Herewith my comments on the calculations.
I'll try to get around to the layout in the next couple of days
(21-08-2014, 12:47 PM)asrisaku Wrote: Hi again
I would like to share my attempt here. I was fun and enjoyed that I implemented transition between 4 to 3 and 3 to 4 and well fit the layout. Would appreciate if I can get further comments.
Thanks
Arnut
PJW