If a carrier is going around on the line and does not enter the expected station.
Start by opening carrier history and entering the id of the carrier. The most recent events of that carrier might contain a clue as to why the carrier is not unloading.
Rail Overload
A carrier will not enter a rail or a bridge that has the overload sensor activated. To check this, open the station in the station settings, expand the setting to view the rail(s) and check if the overload switch has been activated.
Missing Routing
Using the Carrier Status Page, you can enter a carrier number and determine where it is heading. Check that the carrier is heading to the expected rail. If there is a routing error for the carrier, that will also be shown on this page.
Sequenced Unloading
Open Station Settings for the target station. Check if the Sequenced Unloading setting is activated.
If this is the case, you can use the terminal command
Show what carrier is next expected to the first rail of the current station.
Current station must have sequenced unloading enabled.
on the target station to check what is the next expected carrier, it might be a different number than the carrier you are expecting to enter.
You can also use carrier search to find all carriers heading to the same rail. If you sort the search results on the sequence, you should be able to see the "oldest" article/order line and where they are in the system.
Blocking Buffer Calls
If you are using blocking buffer calls, the rail may not be accepting carrier because it needs to wait for earlier buffer calls to arrive first. Check the Buffer Calls page to determine if there are blocking calls heading to this rail.
Line Reader not working / Bad Tag
There may be a problem with a station RFID reader. You can enable the line reporting to check that the reader is correctly scanning carriers.
If the station is reading carriers properly, except the carrier you are interested in, there may be a problem with a bad tag on that carrier. In that case, manually take the carrier down from the line, or use test mode to force it to enter a rail.
Incorrect unloading delay
If the rail unloading arm is opening and closing too early or too late, that would most likely be due to an incorrectly configured unloading delay.
Non functional unloading arm
Use test mode to verify that the unloading arm is functioning correctly.