diff --git a/cv4/a_train.c b/cv4/a_train.c
index 3ecfbc8..8f276b8 100644
--- a/cv4/a_train.c
+++ b/cv4/a_train.c
@@ -2,13 +2,28 @@
 #include <stdio.h>
 
 struct car* add_car(struct car* first,const char* target) {
-    return NULL;
+    struct car* newcar = calloc(1,sizeof(struct car));
+    strcpy(newcar->value, target);
+    struct car* this = first;  
+    while (this->next != NULL) {  
+        this = this->next;  
+    }
+    this->next = newcar;
+    return first;
 }
 
 void print_train(struct car* first) {
+    while(first != NULL)(
+        printf("%s", first->value);
+        first->value = first->next
+    )
 }
 
 void cancel_train(struct car* first) {
+    while(first != NULL){
+        free(first->next);
+        first = first->next;
+    }
 }