diff --git a/cv5/a_train.c b/cv5/a_train.c
index c650eea..632e564 100644
--- a/cv5/a_train.c
+++ b/cv5/a_train.c
@@ -14,9 +14,11 @@ struct car* add_car(struct car* first,const char* target) {
     
     if(first == NULL){
         strcpy(newcar->value, target);
+        newcar->next = NULL;
         return newcar;
     }
-    strcpy(newcar->value,target);    
+    strcpy(newcar->value,target);
+    newcar->next = NULL;    
     struct car *this = first;
     while(this->next != NULL){
         this = this->next;         
@@ -49,7 +51,7 @@ void cancel_train(struct car* first) {
        cancel_train(first->next);
        first->next = NULL;
     }
-    if(first->next == NULL){
+    else if(first->next == NULL){
        free(first);
       //  cancel_train(first->next);
     }
@@ -60,6 +62,9 @@ void cancel_train(struct car* first) {
 
 
 struct car* clear_train(struct car* first, const char* target) {
+    if(first == NULL){
+        return 0;
+    }
     struct car* this = first;
     while(this != NULL){
         if(this->value == target){