diff --git a/src/AbstractRequest.php b/src/AbstractRequest.php
index 8e587ba..3239fbe 100644
--- a/src/AbstractRequest.php
+++ b/src/AbstractRequest.php
@@ -20,7 +20,7 @@
 
 abstract class AbstractRequest implements Request
 {
-    private const BASE_URL = 'https://xmlopen.rejseplanen.dk/bin/rest.exe/';
+    protected const BASE_URL = 'https://xmlopen.rejseplanen.dk/bin/rest.exe/';
     private const API_NAME = 'rejseplan_php_api';
     private const API_VERSION = '3.0';
     private const USER_AGENT = self::API_NAME.'/'.self::API_VERSION;
@@ -126,7 +126,7 @@ abstract protected function configure(OptionsResolver $resolver): void;
 
     abstract protected function getUrl(): string;
 
-    private function makeUrl(): string
+    protected function makeUrl(): string
     {
         $query = array_merge(['format' => 'json'], $this->getQuery());
         $query = http_build_query($query);
diff --git a/src/Journey.php b/src/Journey.php
index 35a136e..2d9d968 100644
--- a/src/Journey.php
+++ b/src/Journey.php
@@ -34,6 +34,11 @@ protected function configure(OptionsResolver $resolver): void
         $resolver->setRequired(['ref']);
     }
 
+    protected function makeUrl(): string
+    {
+        return sprintf('%s%s', self::BASE_URL, $this->options['ref']);
+    }
+
     protected function getUrl(): string
     {
         return 'journeyDetails';