diff --git a/src/openrct2/actions/TrackDesignAction.cpp b/src/openrct2/actions/TrackDesignAction.cpp
index a6cd6017eb..534d2003dd 100644
--- a/src/openrct2/actions/TrackDesignAction.cpp
+++ b/src/openrct2/actions/TrackDesignAction.cpp
@@ -137,10 +137,10 @@ GameActions::Result TrackDesignAction::Execute() const
 
     auto& objManager = OpenRCT2::GetContext()->GetObjectManager();
     auto entryIndex = objManager.GetLoadedObjectEntryIndex(_td.vehicle_object);
-    if (entryIndex == OBJECT_ENTRY_INDEX_NULL)
+    if (entryIndex != OBJECT_ENTRY_INDEX_NULL)
     {
-        // Force a fallback if the entry is not invented yet a td6 of it is selected,
-        // which can happen in select-by-track-type mode
+        // Force a fallback if the entry is not invented yet a track design using it is selected.
+        // This can happen on rides with multiple vehicles where some have been invented and some haven’t.
         if (!ride_entry_is_invented(entryIndex) && !gCheatsIgnoreResearchStatus)
         {
             entryIndex = OBJECT_ENTRY_INDEX_NULL;
diff --git a/src/openrct2/management/Research.cpp b/src/openrct2/management/Research.cpp
index 2b780c0f9e..2d53ddeb32 100644
--- a/src/openrct2/management/Research.cpp
+++ b/src/openrct2/management/Research.cpp
@@ -549,8 +549,11 @@ bool ride_type_is_invented(uint32_t rideType)
     return RideTypeIsValid(rideType) ? _researchedRideTypes[rideType] : false;
 }
 
-bool ride_entry_is_invented(int32_t rideEntryIndex)
+bool ride_entry_is_invented(ObjectEntryIndex rideEntryIndex)
 {
+    if (rideEntryIndex >= std::size(_researchedRideEntries))
+        return false;
+
     return _researchedRideEntries[rideEntryIndex];
 }
 
@@ -562,9 +565,12 @@ void ride_type_set_invented(uint32_t rideType)
     }
 }
 
-void ride_entry_set_invented(int32_t rideEntryIndex)
+void ride_entry_set_invented(ObjectEntryIndex rideEntryIndex)
 {
-    _researchedRideEntries[rideEntryIndex] = true;
+    if (rideEntryIndex >= std::size(_researchedRideEntries))
+        log_error("Tried setting ride entry %u as invented", rideEntryIndex);
+    else
+        _researchedRideEntries[rideEntryIndex] = true;
 }
 
 bool scenery_is_invented(const ScenerySelection& sceneryItem)
diff --git a/src/openrct2/management/Research.h b/src/openrct2/management/Research.h
index cbfa059335..df78517a66 100644
--- a/src/openrct2/management/Research.h
+++ b/src/openrct2/management/Research.h
@@ -138,11 +138,11 @@ void research_insert_ride_entry(ObjectEntryIndex entryIndex, bool researched);
 bool research_insert_scenery_group_entry(ObjectEntryIndex entryIndex, bool researched);
 
 void ride_type_set_invented(uint32_t rideType);
-void ride_entry_set_invented(int32_t rideEntryIndex);
+void ride_entry_set_invented(ObjectEntryIndex rideEntryIndex);
 void scenery_set_invented(const ScenerySelection& sceneryItem);
 void scenery_set_not_invented(const ScenerySelection& sceneryItem);
 bool ride_type_is_invented(uint32_t rideType);
-bool ride_entry_is_invented(int32_t rideEntryIndex);
+bool ride_entry_is_invented(ObjectEntryIndex rideEntryIndex);
 bool scenery_group_is_invented(int32_t sgIndex);
 void scenery_group_set_invented(int32_t sgIndex);
 bool scenery_is_invented(const ScenerySelection& sceneryItem);