Major breakthrough, just some artifacting to resolve

layers/transportation/layer.sql

@@ -96,6 +96,24 @@ RETURNS TABLE(osm_id bigint, geometry geometry, class text, ramp int, oneway int
         )
         UNION ALL
 
+        -- etldoc: osm_railway_linestring_gen2  ->  layer_transportation:z11"
+        SELECT
+            osm_id, geometry, NULL AS highway, railway,
+            service_value(service) AS service,
+            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, z_order
+        FROM osm_railway_linestring_gen2
+        WHERE zoom_level = 11 AND (railway='rail' AND service = '')
+        UNION ALL
+
+        -- etldoc: osm_railway_linestring_gen1  ->  layer_transportation:z12"
+        SELECT
+            osm_id, geometry, NULL AS highway, railway,
+            service_value(service) AS service,
+            is_bridge, is_tunnel, is_ford, is_ramp, is_oneway, z_order
+        FROM osm_railway_linestring_gen1
+        WHERE zoom_level = 12 AND (railway='rail' AND service = '')
+        UNION ALL
+
         -- etldoc: osm_railway_linestring       ->  layer_transportation:z13
         -- etldoc: osm_railway_linestring       ->  layer_transportation:z14_
         SELECT

layers/transportation/mapping.yaml

@@ -1,6 +1,16 @@
-
 generalized_tables:
 
+# etldoc: imposm3 -> osm_railway_linestring_gen2
+  railway_linestring_gen2:
+    source: railway_linestring_gen1
+    tolerance: 40.0
+
+# etldoc: imposm3 -> osm_railway_linestring_gen1
+  railway_linestring_gen1:
+    source: railway_linestring
+    sql_filter: railway='rail' AND service=''
+    tolerance: 20.0
+
 # etldoc: imposm3 -> osm_highway_linestring_gen4
   highway_linestring_gen4:
     source: highway_linestring_gen3