Difference between revisions of "Oneway or Twoway Presignals"
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==Part 1: The Station entrance problem with two entries== | ==Part 1: The Station entrance problem with two entries== | ||
| − | [[Image: | + | |
| + | [[Image:Twoentry2.PNG|thumb|center|404px|The error]] | ||
In this station the combo presignal can make errors, but can you notice why? If presignals F-H are green then upper-right side of combo presignal C is green too. Even if presignals D and E are red, presignal A remains green. The problem is simple: Presignals calculate signal blocks, not the choosable tracks: trains cannot reach platforms F-H from A through C, but presignals CANNOT see this! | In this station the combo presignal can make errors, but can you notice why? If presignals F-H are green then upper-right side of combo presignal C is green too. Even if presignals D and E are red, presignal A remains green. The problem is simple: Presignals calculate signal blocks, not the choosable tracks: trains cannot reach platforms F-H from A through C, but presignals CANNOT see this! | ||
| − | [[Image: | + | [[Image:Twoentry.PNG|thumb|center|404px|Fix this error by making the combo a oneway signal]] |
| − | How to fix this? Just change the combo presignal C to oneway (shown | + | How to fix this? Just change the combo presignal C to oneway (shown above) or add an oneway combo presignal just after it, like below: |
| − | [[Image:Twoentry3.PNG|thumb|center|404px| | + | [[Image:Twoentry3.PNG|thumb|center|404px|Or add a oneway combo presignal is added after it]] |
| − | With this layout, entry presignal A | + | With this layout, entry presignal A won't be affected by the signals for platforms F-H. |
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[[Presignal_Basics|<< Presignal Basics]] | [[Guides:Presignals|^^ Back to Presignals Guides Index]] | [[Priority|Priority >>]] | [[Presignal_Basics|<< Presignal Basics]] | [[Guides:Presignals|^^ Back to Presignals Guides Index]] | [[Priority|Priority >>]] | ||
[[Category:Guides]] | [[Category:Guides]] | ||
Revision as of 18:24, 21 December 2011
<< Presignal Basics | ^^ Back to Presignals Guides Index | Priority >>
Oneway or Twoway Presignals?
Signals have two sides, in the basics part, the other side wasn't important, since trains can't turn back, etc. etc... But in more complex things, a badly placed twoway combo presignal can make errors in your network.
Part 1: The Station entrance problem with two entries
In this station the combo presignal can make errors, but can you notice why? If presignals F-H are green then upper-right side of combo presignal C is green too. Even if presignals D and E are red, presignal A remains green. The problem is simple: Presignals calculate signal blocks, not the choosable tracks: trains cannot reach platforms F-H from A through C, but presignals CANNOT see this!
How to fix this? Just change the combo presignal C to oneway (shown above) or add an oneway combo presignal just after it, like below:
With this layout, entry presignal A won't be affected by the signals for platforms F-H.
<< Presignal Basics | ^^ Back to Presignals Guides Index | Priority >>
