question: protected void updateLocoPanes ( RouteLocation rl ) { if ( Setup . isPrintHeadersEnabled ( ) ) { JLabel header = new JLabel ( Tab + trainCommon . getPickupEngineHeader ( ) ) ; setLabelFont ( header ) ; pPickupLocos . add ( header ) ; JLabel headerDrop = new JLabel ( Tab + trainCommon . getDropEngineHeader ( ) ) ; setLabelFont ( headerDrop ) ; pSetoutLocos . add ( headerDrop ) ; } List < Engine > engList = engManager . getByTrainBlockingList ( _train ) ; for ( Engine engine : engList ) { if ( engine . getRouteLocation ( ) == rl && engine . getTrack ( ) != null ) { locoPane . setVisible ( true ) ; pPickupLocos . setVisible ( true ) ; rollingStock . add ( engine ) ; engine . addPropertyChangeListener ( this ) ; JCheckBox checkBox ; if ( checkBoxes . containsKey ( "ep" + engine . getId ( ) ) ) { checkBox = checkBoxes . get ( "ep" + engine . getId ( ) ) ; } else { checkBox = new JCheckBox ( trainCommon . pickupEngine ( engine ) ) ; setCheckBoxFont ( checkBox ) ; addCheckBoxAction ( checkBox ) ; checkBoxes . put ( "ep" + engine . getId ( ) , checkBox ) ; } if ( isSetMode && ! checkBox . isSelected ( ) ) { pPickupLocos . add ( addSet ( engine ) ) ; } else { pPickupLocos . add ( checkBox ) ; } } if ( engine . getRouteDestination ( ) == rl ) { locoPane . setVisible ( true ) ; pSetoutLocos . setVisible ( true ) ; rollingStock . add ( engine ) ; engine . addPropertyChangeListener ( this ) ; JCheckBox checkBox ; if ( checkBoxes . containsKey ( "es" + engine . getId ( ) ) ) { checkBox = checkBoxes . get ( "es" + engine . getId ( ) ) ; } else { checkBox = new JCheckBox ( trainCommon . dropEngine ( engine ) ) ; setCheckBoxFont ( checkBox ) ; addCheckBoxAction ( checkBox ) ; checkBoxes . put ( "es" + engine . getId ( ) , checkBox ) ; } if ( isSetMode && ! checkBox . isSelected ( ) ) { pSetoutLocos . add ( addSet ( engine ) ) ; } else { pSetoutLocos . add ( checkBox ) ; } } } pPickupLocos . add ( new JLabel ( Space ) ) ; pSetoutLocos . add ( new JLabel ( Space ) ) ; }
target:  Uses "ep" prefix to denote a checkbox with an engine pick up, and "es" for an engine set out.