diff --git a/core/lib/Drupal/Core/Routing/RouteCompiler.php b/core/lib/Drupal/Core/Routing/RouteCompiler.php
index 639feff..50627c4 100644
--- a/core/lib/Drupal/Core/Routing/RouteCompiler.php
+++ b/core/lib/Drupal/Core/Routing/RouteCompiler.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Routing;
 
+use Drupal\Component\Utility\Unicode;
 use Symfony\Component\Routing\RouteCompilerInterface;
 use Symfony\Component\Routing\Route;
 use Symfony\Component\Routing\RouteCompiler as SymfonyRouteCompiler;
@@ -67,7 +68,8 @@ public static function compile(Route $route) {
    * Returns the pattern outline.
    *
    * The pattern outline is the path pattern but normalized so that all
-   * placeholders are equal strings and default values are removed.
+   * placeholders are equal strings and default values are removed, and the path
+   * is converted to lowercase.
    *
    * @param string $path
    *   The path for which we want the normalized outline.
@@ -76,7 +78,7 @@ public static function compile(Route $route) {
    *   The path pattern outline.
    */
   public static function getPatternOutline($path) {
-    return preg_replace('#\{\w+\}#', '%', $path);
+    return Unicode::strtolower(preg_replace('#\{\w+\}#', '%', $path));
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Routing/RouteProvider.php b/core/lib/Drupal/Core/Routing/RouteProvider.php
index 937cff7..a8dc186 100644
--- a/core/lib/Drupal/Core/Routing/RouteProvider.php
+++ b/core/lib/Drupal/Core/Routing/RouteProvider.php
@@ -10,6 +10,7 @@
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Cache\CacheTagsInvalidatorInterface;
+use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Path\CurrentPathStack;
 use Drupal\Core\PathProcessor\InboundPathProcessorInterface;
 use Drupal\Core\State\StateInterface;
@@ -147,7 +148,9 @@ public function __construct(Connection $connection, StateInterface $state, Curre
    */
   public function getRouteCollectionForRequest(Request $request) {
     // Cache both the system path as well as route parameters and matching
-    // routes.
+    // routes. We can not yet convert the path to lowercase since wildcard path
+    // portions may be case sensitive if they contain data like a base64 encoded
+    // token.
     $cid = 'route:' . $request->getPathInfo() . ':' .  $request->getQueryString();
     if ($cached = $this->cache->get($cid)) {
       $this->currentPath->setPath($cached->data['path'], $request);
@@ -155,14 +158,14 @@ public function getRouteCollectionForRequest(Request $request) {
       return $cached->data['routes'];
     }
     else {
-      // Just trim on the right side.
       $path = $request->getPathInfo();
-      $path = $path === '/' ? $path : rtrim($request->getPathInfo(), '/');
+      // Just trim path on the right side.
+      $path = $path === '/' ? $path : rtrim($path, '/');
       $path = $this->pathProcessor->processInbound($path, $request);
       $this->currentPath->setPath($path, $request);
       // Incoming path processors may also set query parameters.
       $query_parameters = $request->query->all();
-      $routes = $this->getRoutesByPath(rtrim($path, '/'));
+      $routes = $this->getRoutesByPath($path);
       $cache_value = [
         'path' => $path,
         'query' => $query_parameters,
@@ -317,15 +320,17 @@ public function getRoutesByPattern($pattern) {
    * Get all routes which match a certain pattern.
    *
    * @param string $path
-   *   The route pattern to search for (contains % as placeholders).
+   *   The route pattern to search for.
    *
    * @return \Symfony\Component\Routing\RouteCollection
    *   Returns a route collection of matching routes.
    */
   protected function getRoutesByPath($path) {
     // Split the path up on the slashes, ignoring multiple slashes in a row
-    // or leading or trailing slashes.
-    $parts = preg_split('@/+@', $path, NULL, PREG_SPLIT_NO_EMPTY);
+    // or leading or trailing slashes. Convert to lower case here so we can
+    // have a case insensitive match from the incoming path to the pattern
+    // outlines from \Drupal\Core\Routing\RouteCompiler::getPatternOutline()
+    $parts = preg_split('@/+@', Unicode::strtolower($path), NULL, PREG_SPLIT_NO_EMPTY);
 
     $collection = new RouteCollection();