Compact Layout of ICS Crossovers
BNSF has begun installing Independently Controlled Switches (ICS) at crossovers in multiple-main-track territory. These ICS plants have unique controls and indications for each turnout and, typically, an OS (TK) bit for both the normal and reverse legs of each turnout. Accurately displaying all of these OS blocks can take up a lot of real estate on a layout, and my initial attempt at depicting such a CP was rather cumbersome (see PA Jct in the Decoding Mnemonics tutorial).
When I started to create the massive layout required for BNSF's Orin Subdivision, I quickly realized that I needed a more efficient method of displaying ICS crossovers than having to use the Media:CompactICSCrossovers.tees.gif -shaped elements would permit. Thinking back to some of the TB3 skills I learned while creating simulations, I concluded that manual block connections would do the trick. (Note that I have a standard convention for laying out interlockings that takes up more space than if trackage was crammed onto the layout in the most efficient manner possible; I choose to do this for aesthetic purposes at the possible detriment of real-estate usage.)
This method uses only the Media:CompactICSCrossovers.angles.gif -shaped elements to connect the turnouts; the Media:CompactICSCrossovers.tees.gif s remain in use to subdivide adjacent OSes on the through tracks.
Laying out the interlocking
Start by laying out the interlocking in its final form, but omit the connecting elements between crossover turnouts:
Next, add only one-half of each pair of Media:CompactICSCrossovers.angles.gif elements to the crossovers:
Now, drop the other halves of the crossover connections floating in space away from their final locations:
If you haven't already done so, take a minute to go through and set all the tracks within the plant as connecting blocks.
Creating ICS crossovers
You're now ready to set up the crossovers. Mouse-over one of the one-half elements you placed earlier to find its block number:
This element is block #0701 (TB3 drops the leading zero in the status bar). Right-click on the corresponding other half of the connection and edit the General Properties. From the "Left Device Manual block" pulldown, select the block number you identified in the previous step; alternately, you can use the TAB key to highlight this field and type in the number to scroll through the list (i.e., typing 0-9-5 will take you to block 0950; if you make a mistake, simply hit an arrow key to clear the key-in memory and type the value again). The block you wish to connect to should now be highlighted:
Click Apply to assign the setting; if an error occurs, such as attempting to connect to a block that already has a connection defined, a pop-up window will display. If this happens, cancel out of the General Properties window and try to track down where the error lies (usually, File -> Create Layout will help identify problems).
Mousing over both halves of the connection should show that they are linked to each other:
Next, use the fence tool to select the floating half: Media:CompactICSCrossovers.07-west-bill.gif ...and drag it into its final position:
If you mouse-over the two halves once again, they should still have separate block numbers; note that the half which had been floating has automatically had its turnout connection assigned.
Repeat this process for the remainder of the crossovers:
Assigning component names
ICS interlockings have been observed to have either one address for the entire interlocking or one address for each through track; these varied setups exist in both ARES and ATCS territory. Regardless of how many addresses are used, I assign one station name in TB3 to the entire interlocking and assign component names for each track using appropriate prefixes (1WAK and 1EGK for MT1, 2WAK and 2EGK for MT2, etc.). Address names are in the format Interlocking Name+Track Name for each track (W Bill MT1, W Bill MT2, etc.).
Assigning TK mnemonics for connecting blocks is slightly different than for a regular approach block, and only needs to be done when there is more than one TK per through track (as shown in the Mnemonic Quick Reference, ATCSMon will automatically assign appropriate TK values to the layout based on the CP's entrance and exit signals for each track). In the General Properties window, enter the block name in the "Remote monitor name" field at bottom-right:
As with all components, only one alphanumeric prefix is allowed for each individual TK mnemonic in the form X:nTK, where n is assigned 0-9 or A-Z; thus, if there are 18 TKs within the plant, they are assigned 1TK, 2TK, ... 9TK, 0TK, ATK, ... HTK. To maintain a consistent naming convention, I assign values for n starting with 1 at top-left, proceed to the right across the first track, then left-to-right for the top half of the XO connections, then left-to-right for bottom half of the XO connections, then left-to-right for the second track, and so on. Mouse-over the Orin Sub layout in ATCSMon to see the final mnemonic layout for one of these ICS interlockings.
It is worth noting that the second and fourth turnouts on MT3 at W Bill do not have separate TK bits for the reverse legs of the turnout, while other single-switch locations on the Orin Sub (such as the South Black Thunder Mine lead at Crossover 49.2 MT1 and Cordero Rojo Mine lead at W Cordero Jct MT3) do have separate TK bits for the diverging leg. -- Main.DaveHonan - 08 Nov 2008