To display a trailer on the map, tick the checkbox on its left. As
trailers do not have their own coordinates, they borrow their location
from units to which they are bound. Click on trailer's name in the list
to center the map on its position. A bound trailer is represented by a
small icon at the bottom right corner of unit's icon. If a trailer is
not attached to any unit at the moment, its last known position is shown
(with a bigger icon). If there is no data about trailer's location (for
example, if it has never been bound to any unit), such a trailer is not
shown on the map.
Note that in order trailers to be displayed on the map you should check if the corresponding layer icon in the main menu is active.
If a trailer is bound to a unit, unit icon is displayed on the right of
trailer's name. If you place the cursor over this icon, the unit's
tooltip is displayed (the same as in the Monitoring panel).