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Occupancy Blocks, or more properly named "track circuits", are portions of track having one or more Sensors to detect occupancy by Trains. These rail blocks, called OBlocks, are usually separated by gaps cut in the track which isolate the detecting sensors. However this is not always the case, since optical sensors might also be used to detect occupancy in a section of track. But whatever method is used to determine a block and the means of detecting its occupancy, there is some point that separates one block from another block. This dividing line between two blocks, whether a physical gap or an imaginary line, marks a transition from one block to another. These transition points are called Portals.
Undoubtably you created Blocks on your layout because it was important for you to know when one section of track was exited and another was entered. One or more track circuits might be grouped together to make a prototypical Block, i.e. a section of track whose use is governed by signals. This can provide Interlocking. The Signals governing a Block are logically placed at the Portal points. If you have signals on your layout, consider where they are located. Most likely they are placed near dividing points between Blocks. So regardless of the name, Portals are a significant concept.
There may be many ways to traverse an OBlock. For example, in the diagram below both
OPaths 31a and 31b traverse Block 31.
A Path within a Block will enter at one Portal and exit through another Portal. See for example Path 31b in the diagram, which enters Block 31 through Portal 2-31b and exits via Portal 31-5.
Or a Path may terminate within the Block, that is, the Path is a spur. Again, Portals are a useful concept to indicate these entrance and exit points.
Note that a Path must have at least one Portal for an entry/exit point and cannot have more than two Portals. A Path is unambiguously defined by specifying the Turnouts and their settings for a Train to proceed safely through the Block.
OBlocks, Portals and OPaths can be created and edited using the methods described below, or they can also be created and edited from a WYSIWYG graphical interface described in the Circuit Builder Help.
Circuit Builder can be used you if you have a Control Panel Editor track diagram using track icons showing your layout. Otherwise you will need to use the tables below. See Creating and Editing OBlocks, Portals and OPaths for more details on using the tables.
In JMRi Preferences > Display you can choose your preferred interface to edit these items in tables (restart required):
The information in the tables is basically the same as you find in the desktop style, but
instead of an empty bottom row. New items are added by clicking one of the [Add...] buttons
below the tables. This opens up a pane to configure all items for a new OBlock etc. Feedback
in the status bar and tooltips assists to fill in the correct information.
When you are done, click [Create] to complete the definition in JMRI, after which it shows up as an extra row in the table.
To edit an item in one of the tables, click the [Edit] button at the end of its table row.
To prevent duplication, please refer to the detailed description of all items below.
Specific help is accessible via the Window Help menu.
The tables to edit OBlocks etc are contained within a single frame that can be minimized or closed. The individual table frames can be minimized within this parent frame using the familiar OS window buttons.
Each of the tables in the Occupancy Block, Portal, Path Frame has a bottom row with blank entries. Entering data into these entries and pressing the 'Enter' key will create a new item in the table. 'Drag and Drop' and 'Copy and Paste' are implemented to provide easy ways to move text from table to table.
This table is initially sorted by the System Name of the OBlocks. This means that when a
new row is added the entry will jump to its position in the sort. After entering a new
OBlock, you may find it at the top of the window should you need to do further editing.
since 2.12You can sort the table by clicking on a column header.
Several columns are hidden in the OBlock table. To hide/unhide a column, right click in the Header portion of the table.
The Portal table has columns for the blocks each portal separates. You do not need to be concerned about the direction of travel through the portal. It does not matter which side of the portal the blocks names are entered, since the algorithms that compute train routes will decipher the correct entrance and exit points.
For each signal on your layout, make an entry in the Signal Table. This Signal will control the actions of any warranted train - changing its speed according to the Signal's indication when the train reaches the Portal where the signal is placed. That is, the Signal 'protects' the Blocks beyond the Portal. The Signal may be either a Signal Mast or a Signal Head.
A Warrant detects the signal Aspect when it's train enters the approach Block and - if needed - prepares to change the speed before it reaches the protected Block. Any speed change is ramped down to the speed required by the Signal. The Warrant calculates when the speed ramp-down should begin using the parameters involved with the Speed Profile or throttle factor of the engine (see Warrants). The point where the speed change should complete can be adjusted (+/-) by the above Length amount, should that be desirable.
Likewise, when the Signal indicates a Clear or increased speed from a stopped or reduced speed condition, the speed will be ramped up to the allowed or recorded speed.
Each Block in the Occupancy Block Table will have one or more Paths in it. Pressing the Paths button in a row of the Occupancy Block Table will open this table. Direction of the path is immaterial. 'from' and 'to' do not have to correspond to any particular side of the Block; they are just Portal names for the Path that traverses from 'this portal' to 'that portal'.
To read about how OBlocks, Portals and OPaths can be used to generate train Routes and make automated train Scripts, see Warrants.
See Creating and Editing OBlocks, Portals and OPaths for more details on using these Tables.
See Circuit Builder for creating and editing OBlocks, Portals and OPaths from a graphical representation of your track plan.
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