01-10-2013, 08:21 PM
I have been asked the following question
I have some doubt regarding junction protection signal that which type of signal aspect should we use at junction 3 aspect or 4 aspect? which one would be best option.
If I opt 3 aspect signalling in that case at junction I need transition from 3 to 4 aspect signalling.
There is some relevant information linked in the posts above, but put simply, it depends on the situation.
You will need to provide an appropriate system for both lines - the appropriate number of aspects for each of the two lines that come together at the junction.
Depending on the relative speeds of the two lines or the points at the junction, moving from, say, 3 to 4 aspects may be simple with a 3 aspect junction signal because you may have full braking between it at Y and the next (4 aspect) signal at R. If the layout allows higher speed, then following a standard 3-4 aspect sequence transition before the junction (having a YGY signal at about half braking distance between the last 3 aspect signal and the first 4 aspect signal (probably the junction signal) signal may be needed.
Please let me know if this does not answer the query.
Peter
I have some doubt regarding junction protection signal that which type of signal aspect should we use at junction 3 aspect or 4 aspect? which one would be best option.
If I opt 3 aspect signalling in that case at junction I need transition from 3 to 4 aspect signalling.
There is some relevant information linked in the posts above, but put simply, it depends on the situation.
You will need to provide an appropriate system for both lines - the appropriate number of aspects for each of the two lines that come together at the junction.
Depending on the relative speeds of the two lines or the points at the junction, moving from, say, 3 to 4 aspects may be simple with a 3 aspect junction signal because you may have full braking between it at Y and the next (4 aspect) signal at R. If the layout allows higher speed, then following a standard 3-4 aspect sequence transition before the junction (having a YGY signal at about half braking distance between the last 3 aspect signal and the first 4 aspect signal (probably the junction signal) signal may be needed.
Please let me know if this does not answer the query.
Peter