diff --git a/ram/portal/templates/cards/roster.html b/ram/portal/templates/cards/roster.html
index 548d49f..8cd923d 100644
--- a/ram/portal/templates/cards/roster.html
+++ b/ram/portal/templates/cards/roster.html
@@ -60,7 +60,7 @@
                   </tr>
                   <tr>
                     <th scope="row">Item number</th>
-                    <td>{{ d.item.item_number }}{%if d.item.set %} | <a class="badge text-bg-primary" href="{% url 'manufacturer' manufacturer=d.item.manufacturer search=d.item.item_number %}">SET</a>{% endif %}</td>
+                    <td>{{ d.item.item_number }}{%if d.item.set %} | <a class="badge text-bg-primary" href="{% url 'manufacturer' manufacturer=d.item.manufacturer.slug search=d.item.item_number_slug %}">SET</a>{% endif %}</td>
                   </tr>
                 </tbody>
               </table>
diff --git a/ram/portal/templates/rollingstock.html b/ram/portal/templates/rollingstock.html
index 9a9e0d3..ea89540 100644
--- a/ram/portal/templates/rollingstock.html
+++ b/ram/portal/templates/rollingstock.html
@@ -120,7 +120,7 @@
                       </tr>
                       <tr>
                         <th scope="row">Item number</th>
-                        <td>{{ rolling_stock.item_number }}{%if rolling_stock.set %} | <a class="badge text-bg-primary" href="{% url 'manufacturer' manufacturer=rolling_stock.manufacturer search=rolling_stock.item_number %}">SET</a>{% endif %}</td>
+                        <td>{{ rolling_stock.item_number }}{%if rolling_stock.set %} | <a class="badge text-bg-primary" href="{% url 'manufacturer' manufacturer=rolling_stock.manufacturer.slug search=rolling_stock.item_number_slug %}">SET</a>{% endif %}</td>
                       </tr>
                     </tbody>
                   </table>
@@ -173,7 +173,7 @@
                       </tr>
                       <tr>
                         <th scope="row">Item number</th>
-                        <td>{{ rolling_stock.item_number }}{%if rolling_stock.set %} | <a class="badge text-bg-primary" href="{% url 'manufacturer' manufacturer=rolling_stock.manufacturer search=rolling_stock.item_number %}">SET</a>{% endif %}</td>
+                        <td>{{ rolling_stock.item_number }}{%if rolling_stock.set %} | <a class="badge text-bg-primary" href="{% url 'manufacturer' manufacturer=rolling_stock.manufacturer.slug search=rolling_stock.item_number_slug %}">SET</a>{% endif %}</td>
                       </tr>
                       <tr>
                         <th scope="row">Era</th>
diff --git a/ram/portal/views.py b/ram/portal/views.py
index fe6cfad..3a598e8 100644
--- a/ram/portal/views.py
+++ b/ram/portal/views.py
@@ -50,6 +50,15 @@ def get_order_by_field():
         return (fields[2], fields[0], fields[1], fields[3])
 
 
+class Render404(View):
+    def get(self, request, exception):
+        return render(
+            request,
+            "base.html",
+            {"title": "404 page not found"}
+        )
+
+
 class GetData(View):
     title = "Home"
     template = "roster.html"
@@ -229,27 +238,33 @@ class SearchObjects(View):
 
 class GetManufacturerItem(View):
     def get(self, request, manufacturer, search="all", page=1):
+        manufacturer = get_object_or_404(
+            Manufacturer,
+            slug__iexact=manufacturer
+        )
+
         if search != "all":
             rolling_stock = get_list_or_404(
                 RollingStock.objects.order_by(*get_order_by_field()),
                 Q(
-                    Q(manufacturer__name__iexact=manufacturer)
-                    & Q(item_number__exact=search)
+                    Q(manufacturer=manufacturer)
+                    & Q(item_number_slug__exact=search)
                 )
             )
             title = "{0}: {1}".format(
-                rolling_stock[0].manufacturer,
-                search
+                manufacturer,
+                # all returned records must have the same `item_number``;
+                # just pick it up the first result, otherwise `search`
+                rolling_stock[0].item_number if rolling_stock else search
             )
         else:
-            rolling_stock = get_list_or_404(
-                RollingStock.objects.order_by(*get_order_by_field()),
-                Q(rolling_class__manufacturer__slug__iexact=manufacturer)
-                | Q(manufacturer__slug__iexact=manufacturer)
-            )
-            title = "Manufacturer: {0}".format(
-                    get_object_or_404(Manufacturer, slug__iexact=manufacturer)
+            rolling_stock = (
+                RollingStock.objects.order_by(*get_order_by_field()).filter(
+                    Q(manufacturer=manufacturer)
+                    | Q(rolling_class__manufacturer=manufacturer)
                 )
+            )
+            title = "Manufacturer: {0}".format(manufacturer)
 
         data = []
         for item in rolling_stock:
diff --git a/ram/ram/__init__.py b/ram/ram/__init__.py
index 8930ac0..5d0a7f6 100644
--- a/ram/ram/__init__.py
+++ b/ram/ram/__init__.py
@@ -1,4 +1,4 @@
 from ram.utils import git_suffix
 
-__version__ = "0.12.2"
+__version__ = "0.12.3"
 __version__ += git_suffix(__file__)
diff --git a/ram/ram/urls.py b/ram/ram/urls.py
index d5c851c..52e0ff4 100644
--- a/ram/ram/urls.py
+++ b/ram/ram/urls.py
@@ -22,6 +22,9 @@ from django.contrib import admin
 from django.urls import include, path
 
 from ram.views import UploadImage
+from portal.views import Render404
+
+handler404 = Render404.as_view()
 
 urlpatterns = [
     path("", lambda r: redirect("portal/")),
diff --git a/ram/roster/migrations/0026_rollingstock_item_number_slug.py b/ram/roster/migrations/0026_rollingstock_item_number_slug.py
new file mode 100644
index 0000000..d2d37c7
--- /dev/null
+++ b/ram/roster/migrations/0026_rollingstock_item_number_slug.py
@@ -0,0 +1,31 @@
+# Generated by Django 5.0.4 on 2024-04-23 21:10
+
+from django.db import migrations, models
+from ram.utils import slugify
+
+
+def gen_item_number_slug(apps, schema_editor):
+    RollingStock = apps.get_model('roster', 'RollingStock')
+    for row in RollingStock.objects.all():
+        if row.item_number:
+            row.item_number_slug = slugify(row.item_number)
+            row.save(update_fields=['item_number_slug'])
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("roster", "0025_rollingstock_set_alter_rollingstock_era_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="rollingstock",
+            name="item_number_slug",
+            field=models.CharField(blank=True, editable=False, max_length=32),
+        ),
+        migrations.RunPython(
+            gen_item_number_slug,
+            reverse_code=migrations.RunPython.noop
+        ),
+    ]
diff --git a/ram/roster/models.py b/ram/roster/models.py
index 3cbda4e..3febde0 100644
--- a/ram/roster/models.py
+++ b/ram/roster/models.py
@@ -79,6 +79,11 @@ class RollingStock(models.Model):
         blank=True,
         help_text="Catalog item number or code",
     )
+    item_number_slug = models.CharField(
+        max_length=32,
+        blank=True,
+        editable=False
+    )
     set = models.BooleanField(
         default=False,
         help_text="Part of a set",