(svn r21800) -Fix [FS#3569]: under certain circumstances one could crash a competitor's train; take the lazy non-future proof version of the fix from the 1.0 branch as fixing the real bug is significantly more complex and might even break some backwards compatability if not done perfectly

src/train_cmd.cpp

@@ -2813,6 +2813,9 @@ static Vehicle *FindTrainCollideEnum(Vehicle *v, void *data)
 	/* not a train or in depot */
 	if (v->type != VEH_TRAIN || Train::From(v)->track == TRACK_BIT_DEPOT) return NULL;
 
+	/* do not crash into trains of another company. */
+	if (v->owner != tcc->v->owner) return NULL;
+
 	/* get first vehicle now to make most usual checks faster */
 	Train *coll = Train::From(v)->First();