I'll need to defer feedback on the calcs and layout until I have more time, but yes you will find that different areas will have different requirements.
Generically if you have a line signalled with 2 aspect signals (isolated 3 aspect signalling) diverging from a 4 aspect signalled line then the junction signal for the diverging route may be arranged to show just red or green which authorises to train to travel a considerable distance, passing a single yellow distant to a red at the first stop signal.
In the opposite direction, the junction signal from the branch authorising movement onto the 4 aspect line at the convergence would most likely be a three aspect signal as the speeds are probably such that when displaying a single yellow that there would be full braking distance at the junction speed to be able to stop at the first 4-aspect displaying red. The branch would have a yellow/green distant signal (plated with s delta plate) on the approach to this 3-aspect.
Otherwise if the first 4-aspect beyond the convergence isn't sufficiently far from the junction protecting signal for the attainable speed, then the junction protecting signal on the branch would need to be a 4-aspect in which case its distant would be a 3 aspect head but a yellow/green/yellow (and plated with a delta plate).
I'll respond in more detail when I have had a chance to look at your attempt; I have written this without having looked at all and just on the basis of the text of your post so hopefully I have understood your query correctly.
Similarly item2 will have to wait until I can look.
Generically if you have a line signalled with 2 aspect signals (isolated 3 aspect signalling) diverging from a 4 aspect signalled line then the junction signal for the diverging route may be arranged to show just red or green which authorises to train to travel a considerable distance, passing a single yellow distant to a red at the first stop signal.
In the opposite direction, the junction signal from the branch authorising movement onto the 4 aspect line at the convergence would most likely be a three aspect signal as the speeds are probably such that when displaying a single yellow that there would be full braking distance at the junction speed to be able to stop at the first 4-aspect displaying red. The branch would have a yellow/green distant signal (plated with s delta plate) on the approach to this 3-aspect.
Otherwise if the first 4-aspect beyond the convergence isn't sufficiently far from the junction protecting signal for the attainable speed, then the junction protecting signal on the branch would need to be a 4-aspect in which case its distant would be a 3 aspect head but a yellow/green/yellow (and plated with a delta plate).
I'll respond in more detail when I have had a chance to look at your attempt; I have written this without having looked at all and just on the basis of the text of your post so hopefully I have understood your query correctly.
Similarly item2 will have to wait until I can look.
(24-09-2012, 08:57 AM)Nagasri.Jonna Wrote: Hi PJW,
We are attaching solved 2011 layout for module 2.Please find and we got some doubts while solving the layout:
1. when we calculate headway for branch line between A&D, we got 2 aspect signalling. For C to F, we got 4 aspect signalling.
Kindly suggest, how to make transition between 2 and 4 aspect signalling or can we show 4-aspect for all lines as we followed in yard.
2. What are the considerations, when there is head shunt or run round lines in the yard?
Regards,
Nagasri.J
PJW