diff --git a/src/vehicle.cpp b/src/vehicle.cpp
--- a/src/vehicle.cpp
+++ b/src/vehicle.cpp
@@ -2359,7 +2359,7 @@ const GroundVehicleCache *Vehicle::GetGr
  * Calculates the set of vehicles that will be affected by a given selection.
  * @param set Set of affected vehicles.
  * @param v First vehicle of the selection.
- * @param num_vehicles Number of vehicles in the selection.
+ * @param num_vehicles Number of vehicles in the selection (not counting articulated parts).
  * @pre \c set must be empty.
  * @post \c set will contain the vehicles that will be refitted.
  */
@@ -2367,27 +2367,20 @@ void GetVehicleSet(VehicleSet &set, Vehi
 {
 	if (v->type == VEH_TRAIN) {
 		Train *u = Train::From(v);
-		/* If the first vehicle in the selection is part of an articulated vehicle, add the previous parts of the vehicle. */
-		if (u->IsArticulatedPart()) {
-			u = u->GetFirstEnginePart();
-			while (u->index != v->index) {
-				set.Include(u->index);
-				u = u->GetNextArticulatedPart();
-			}
-		}
+		/* Only include whole vehicles, so start with the first articulated part */
+		u = u->GetFirstEnginePart();
 
-		for (;u != NULL && num_vehicles > 0; num_vehicles--, u = u->Next()) {
-			/* Include current vehicle in the selection. */
-			set.Include(u->index);
+		/* Include num_vehicles vehicles, not counting articulated parts */
+		for (; u != NULL && num_vehicles > 0; num_vehicles--) {
+			do {
+				/* Include current vehicle in the selection. */
+				set.Include(u->index);
 
-			/* If the vehicle is multiheaded, add the other part too. */
-			if (u->IsMultiheaded()) set.Include(u->other_multiheaded_part->index);
-		}
+				/* If the vehicle is multiheaded, add the other part too. */
+				if (u->IsMultiheaded()) set.Include(u->other_multiheaded_part->index);
 
-		/* If the last vehicle is part of an articulated vehicle, add the following parts of the vehicle. */
-		while (u != NULL && u->IsArticulatedPart()) {
-			set.Include(u->index);
-			u = u->Next();
+				u = u->Next();
+			} while (u != NULL && u->IsArticulatedPart());
 		}
 	}
 }
diff --git a/src/vehicle_cmd.cpp b/src/vehicle_cmd.cpp
--- a/src/vehicle_cmd.cpp
+++ b/src/vehicle_cmd.cpp
@@ -245,7 +245,7 @@ static CommandCost GetRefitCost(EngineID
  * This is the vehicle-type independent part of the CmdRefitXXX functions.
  * @param v            The vehicle to refit.
  * @param only_this    Whether to only refit this vehicle, or to check the rest of them.
- * @param num_vehicles Number of vehicles to refit. Zero means the whole chain.
+ * @param num_vehicles Number of vehicles to refit (not counting articulated parts). Zero means the whole chain.
  * @param new_cid      Cargotype to refit to
  * @param new_subtype  Cargo subtype to refit to
  * @param flags        Command flags
@@ -319,7 +319,8 @@ static CommandCost RefitVehicle(Vehicle 
  * - p2 = (bit 0-4)   - New cargo type to refit to.
  * - p2 = (bit 7)     - Refit only this vehicle. Used only for cloning vehicles.
  * - p2 = (bit 8-15)  - New cargo subtype to refit to.
- * - p2 = (bit 16-23) - Number of vehicles to refit. Zero means all vehicles. Only used if "refit only this vehicle" is false.
+ * - p2 = (bit 16-23) - Number of vehicles to refit (not counting articulated parts). Zero means all vehicles.
+ *                      Only used if "refit only this vehicle" is false.
  * @param text unused
  * @return the cost of this operation or an error
  */
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -758,9 +758,14 @@ struct RefitWindow : public Window {
 						if (left_x < 0 && !start_counting) {
 							this->selected_vehicle = u->index;
 							start_counting = true;
+
+							/* Count the first vehicle, even if articulated part */
+							this->num_vehicles++;
+						} else if (start_counting && !u->IsArticulatedPart()) {
+							/* Do not count articulated parts */
+							this->num_vehicles++;
 						}
 
-						if (start_counting) this->num_vehicles++;
 						if (right_x < 0) break;
 					}
 				}