diff --git a/src/lang/english.txt b/src/lang/english.txt
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -2890,6 +2890,9 @@ STR_NEWGRF_INVALID_CARGO_QUANTITY       
 STR_NEWGRF_INVALID_ENGINE                                       :<invalid vehicle model>
 STR_NEWGRF_INVALID_INDUSTRYTYPE                                 :<invalid industry>
 
+# Placeholders for other invalid stuff, e.g. vehicles that have gone (Game Script).
+STR_INVALID_VEHICLE                                             :<invalid vehicle>
+
 # NewGRF scanning window
 STR_NEWGRF_SCAN_CAPTION                                         :{WHITE}Scanning NewGRFs
 STR_NEWGRF_SCAN_MESSAGE                                         :{BLACK}Scanning NewGRFs. Depending on the amount this can take a while...
diff --git a/src/strings.cpp b/src/strings.cpp
--- a/src/strings.cpp
+++ b/src/strings.cpp
@@ -1489,7 +1489,7 @@ static char *FormatString(char *buff, co
 
 					StringID str;
 					switch (v->type) {
-						default: NOT_REACHED();
+						default:           str = STR_INVALID_VEHICLE; break;
 						case VEH_TRAIN:    str = STR_SV_TRAIN_NAME; break;
 						case VEH_ROAD:     str = STR_SV_ROAD_VEHICLE_NAME; break;
 						case VEH_SHIP:     str = STR_SV_SHIP_NAME; break;