diff --git a/src/common/attributes/reduceproduction.c b/src/common/attributes/reduceproduction.c
index 58ece03d2..867ae1b2c 100644
--- a/src/common/attributes/reduceproduction.c
+++ b/src/common/attributes/reduceproduction.c
@@ -24,7 +24,7 @@ age_reduceproduction(attrib *a)
 	int reduce = 100 - (5 * --a->data.sa[1]);
 	if (reduce < 10) reduce = 10;
 	a->data.sa[0] = (short)reduce;
-	return a->data.sa[1];
+    return (a->data.sa[1]>0)?AT_AGE_KEEP:AT_AGE_REMOVE;
 }
 
 attrib_type at_reduceproduction = {
diff --git a/src/common/items/artrewards.c b/src/common/items/artrewards.c
index 08a0bae86..069a04e2c 100644
--- a/src/common/items/artrewards.c
+++ b/src/common/items/artrewards.c
@@ -45,7 +45,7 @@
 static int
 age_peaceimmune(attrib * a)
 {
-  return --a->data.i;
+  return (--a->data.i>0)?AT_AGE_KEEP:AT_AGE_REMOVE;
 }
 
 static attrib_type at_peaceimmune = {
diff --git a/src/common/kernel/karma.c b/src/common/kernel/karma.c
index b3e388b65..d85bf723a 100644
--- a/src/common/kernel/karma.c
+++ b/src/common/kernel/karma.c
@@ -46,7 +46,7 @@ attrib_type at_faction_special = {
 
 int
 age_prayer_timeout(attrib *a) {
-	return --a->data.sa[0];
+  return (--a->data.sa[0]>0)?AT_AGE_KEEP:AT_AGE_REMOVE;
 }
 
 attrib_type at_prayer_timeout = {
diff --git a/src/common/kernel/magic.c b/src/common/kernel/magic.c
index c540e3510..4f1df9d68 100644
--- a/src/common/kernel/magic.c
+++ b/src/common/kernel/magic.c
@@ -151,10 +151,10 @@ a_ageicastle(struct attrib * a)
     ADDMSG(&r->msgs, msg_message("icastle_dissolve", "building", b));
     /* remove_building lets units leave the building */
     remove_building(&r->buildings, b);
-    return 0;
+    return AT_AGE_REMOVE;
   }
   else data->time--;
-  return 1;
+  return AT_AGE_KEEP;
 }
 
 static void
@@ -2345,7 +2345,7 @@ age_unit(attrib * a)
 /* if unit is gone or dead, remove the attribute */
 {
   unit * u = (unit*)a->data.v;
-  return (u!=NULL && u->number>0);
+  return (u!=NULL && u->number>0)?AT_AGE_KEEP:AT_AGE_REMOVE;
 }
 
 attrib_type at_familiarmage = {
diff --git a/src/common/kernel/move.c b/src/common/kernel/move.c
index 5d3177c72..2bf08fe82 100644
--- a/src/common/kernel/move.c
+++ b/src/common/kernel/move.c
@@ -131,8 +131,7 @@ shiptrail_age(attrib *a)
 	traveldir *t = (traveldir *)(a->data.v);
 
 	t->age--;
-	if(t->age == 0) return 0;
-	return 1;
+    return (t->age>0)?AT_AGE_KEEP:AT_AGE_REMOVE;
 }
 
 static int
@@ -170,7 +169,7 @@ age_speedup(attrib *a)
   if (a->data.sa[0] > 0) {
     a->data.sa[0] = a->data.sa[0] - a->data.sa[1];
   }
-  return a->data.sa[0]>0;
+  return (a->data.sa[0]>0)?AT_AGE_KEEP:AT_AGE_REMOVE;
 }
 
 attrib_type at_speedup = {
diff --git a/src/common/kernel/region.c b/src/common/kernel/region.c
index 7bf7673f0..e81248c1c 100644
--- a/src/common/kernel/region.c
+++ b/src/common/kernel/region.c
@@ -203,11 +203,8 @@ static int
 a_agedirection(attrib *a)
 {
   spec_direction *d = (spec_direction *)(a->data.v);
-
-  if (d->duration > 0) d->duration--;
-  else d->duration = 0;
-
-  return d->duration;
+  --d->duration;
+  return (d->duration>0)?AT_AGE_KEEP:AT_AGE_REMOVE;
 }
 
 typedef struct dir_lookup {
diff --git a/src/common/kernel/unit.c b/src/common/kernel/unit.c
index b2bda127d..17059991a 100644
--- a/src/common/kernel/unit.c
+++ b/src/common/kernel/unit.c
@@ -720,7 +720,7 @@ leftship_age(struct attrib * a)
 {
   /* must be aged, so it doesn't affect report generation (cansee) */
   unused(a);
-  return 0; /* remove me */
+  return AT_AGE_REMOVE; /* remove me */
 }
 
 static attrib_type at_leftship = {
diff --git a/src/common/modules/arena.c b/src/common/modules/arena.c
index d9e5ac014..12f3c8542 100644
--- a/src/common/modules/arena.c
+++ b/src/common/modules/arena.c
@@ -197,7 +197,7 @@ age_hurting(attrib * a) {
 	building * b = (building *)a->data.v;
 	unit * u;
 	int active = 0;
-	if (b==NULL) return 0;
+	if (b==NULL) return AT_AGE_REMOVE;
 	for (u=b->region->units;u;u=u->next) {
 		if (u->building==b) {
 			if (u->faction->magiegebiet==M_CHAOS) {
@@ -213,7 +213,7 @@ age_hurting(attrib * a) {
 			ADDMSG(&b->region->msgs, msg_message("cryinpain", "unit", u));
 		}
 	}
-	return 1;
+	return AT_AGE_KEEP;
 }
 
 static void
diff --git a/src/common/modules/wormhole.c b/src/common/modules/wormhole.c
index 128ff7713..099a20a5d 100644
--- a/src/common/modules/wormhole.c
+++ b/src/common/modules/wormhole.c
@@ -98,7 +98,7 @@ wormhole_age(struct attrib * a)
   ADDMSG(&r->msgs, msg_message("wormhole_dissolve", "region", r));
 
   /* age returns 0 if the attribute needs to be removed, !=0 otherwise */
-  return -1;
+  return AT_AGE_KEEP;
 }
 
 static void
diff --git a/src/common/spells/spells.c b/src/common/spells/spells.c
index 4a5d23f5a..96dff7879 100644
--- a/src/common/spells/spells.c
+++ b/src/common/spells/spells.c
@@ -2805,10 +2805,8 @@ static int
 wall_age(border * b)
 {
   wall_data * fd = (wall_data*)b->data.v;
-  if (fd->countdown>0) {
-    if (--fd->countdown==0) return 0;
-  }
-  return fd->countdown;
+  --fd->countdown;
+  return (fd->countdown>0)?AT_AGE_KEEP:AT_AGE_REMOVE;
 }
 
 static region *
@@ -3140,7 +3138,7 @@ dc_age(struct curse * c)
   
   if (r==NULL || mage==NULL || mage->number==0) {
     /* if the mage disappears, so does the spell. */
-    return -1;
+    return AT_AGE_REMOVE;
   }
 
   up = &r->units;
@@ -3161,7 +3159,7 @@ dc_age(struct curse * c)
     if (*up==u) up=&u->next;
   }
 
-  return 0;
+  return AT_AGE_KEEP;
 }
 
 static struct curse_type ct_deathcloud = {
diff --git a/src/common/util/attrib.c b/src/common/util/attrib.c
index aa2be7ec7..e6f8e2353 100644
--- a/src/common/util/attrib.c
+++ b/src/common/util/attrib.c
@@ -242,8 +242,15 @@ a_age(attrib ** p)
 	 * hat Einfluß auf den Besitzer */
 	while(*ap) {
 		attrib * a = *ap;
-		if (a->type->age && a->type->age(a)==0) a_remove(p, a);
-		else ap = &a->next;
+        if (a->type->age) {
+          int result = a->type->age(a);
+          assert(result>=0 || !"age() returned a negative value");
+          if (result==0) {
+            a_remove(p, a);
+            continue;
+          }
+        }
+		ap = &a->next;
 	}
 	return (*p!=NULL);
 }
diff --git a/src/common/util/attrib.h b/src/common/util/attrib.h
index 28d3e3765..a4026a5b4 100644
--- a/src/common/util/attrib.h
+++ b/src/common/util/attrib.h
@@ -18,7 +18,7 @@
 extern "C" {
 #endif
 
-  struct storage;
+struct storage;
 typedef void (*afun)(void);
 
 typedef struct attrib {
@@ -80,6 +80,9 @@ extern void a_write(struct storage * store, const attrib * attribs);
 #define AT_READ_OK 0
 #define AT_READ_FAIL -1
 
+#define AT_AGE_REMOVE 0 /* remove the attribute after calling age() */
+#define AT_AGE_KEEP 1 /* keep the attribute for another turn */
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/common/util/filereader.c b/src/common/util/filereader.c
index 95e2436da..a46e6e445 100644
--- a/src/common/util/filereader.c
+++ b/src/common/util/filereader.c
@@ -217,23 +217,29 @@ getbuf_utf8(FILE * F)
       size_t size;
       int ret;
       
+      if (!quote) {
+        while (*bp==COMMENT_CHAR) {
+          /* comment begins. we need to keep going, to look for CONTINUE_CHAR */
+          comment = true;
+          ++bp;
+        }
+      }
+
       if (*bp=='\n' || *bp=='\r') {
         /* line breaks, shmine breaks */
         break;
       }
 
-      if (*bp==COMMENT_CHAR && !quote) {
-        /* comment begins. we need to keep going, to look for CONTINUE_CHAR */
-        comment = true;
-        ++bp;
-      }
       if (*bp=='"' || *bp=='\'') {
         if (quote==*bp) {
           quote = 0;
-          if (cp<fbuf+MAXLINE) *cp++ = *bp++;
+          if (cp<fbuf+MAXLINE) *cp++ = *bp;
+          ++bp;
+          continue;
         } else if (!quote) {
           quote = *bp++;
           if (cp<fbuf+MAXLINE) *cp++ = quote;
+          continue;
         }
       }
 
diff --git a/src/eressea/lua/building.cpp b/src/eressea/lua/building.cpp
index 534075ad4..2bf7c8e18 100644
--- a/src/eressea/lua/building.cpp
+++ b/src/eressea/lua/building.cpp
@@ -50,30 +50,28 @@ lc_age(struct attrib * a)
   int retval = -1;
 
   assert(b!=NULL);
-  if (fname==NULL) return -1;
-
-  lua_State * L = (lua_State *)global.vm_state;
-  if (is_function(L, fname)) {
-    try {
-      if (fparam) {
-#ifdef TUNNELS /* TODO: Why does this crash? */
-        std::string param(fparam);
-        retval = luabind::call_function<int>(L, fname, *b, param);
-#endif
-      } else {
-        retval = luabind::call_function<int>(L, fname, *b);
+  if (fname!=NULL) {
+    lua_State * L = (lua_State *)global.vm_state;
+    if (is_function(L, fname)) {
+      try {
+        if (fparam) {
+          std::string param(fparam);
+          retval = luabind::call_function<int>(L, fname, *b, param);
+        } else {
+          retval = luabind::call_function<int>(L, fname, *b);
+        }
+      }
+      catch (luabind::error& e) {
+        lua_State* L = e.state();
+        const char* error = lua_tostring(L, -1);
+        log_error(("An exception occured while %s tried to call '%s': %s.\n",
+          buildingname(b), fname, error));
+        lua_pop(L, 1);
+        /* std::terminate(); */
       }
     }
-    catch (luabind::error& e) {
-      lua_State* L = e.state();
-      const char* error = lua_tostring(L, -1);
-      log_error(("An exception occured while %s tried to call '%s': %s.\n",
-        buildingname(b), fname, error));
-      lua_pop(L, 1);
-      std::terminate();
-    }
   }
-  return retval;
+  return (retval!=0)?AT_AGE_KEEP:AT_AGE_REMOVE;
 }
 
 static int
diff --git a/src/scripts/eressea/tunnels.lua b/src/scripts/eressea/tunnels.lua
index f0b1771ed..592f6a101 100644
--- a/src/scripts/eressea/tunnels.lua
+++ b/src/scripts/eressea/tunnels.lua
@@ -30,7 +30,7 @@ end
 -- export, will be called from lc_age()
 function tunnel_action(b, param)
   local r = nil
-  print("Tunnel from " .. b .. " [" .. param .. "]")
+  print("Tunnel from " .. tostring(b) .. " [" .. param .. "]")
   if tonumber(param)~=nil then
     r = get_region_by_id(tonumber(param))
   end
@@ -43,7 +43,7 @@ function tunnel_action(b, param)
       end
       if rto~=nil then
         u.region = rto
-        print(" - teleported " .. u .. " to " .. rto)
+        print(" - teleported " .. tostring(u) .. " to " .. tostring(rto))
       end
     end
   end
diff --git a/src/scripts/run-tests.lua b/src/scripts/run-tests.lua
index 35660c497..7295e164c 100644
--- a/src/scripts/run-tests.lua
+++ b/src/scripts/run-tests.lua
@@ -94,13 +94,52 @@ function test_287()
   write_game("287.dat", "binary")
 end
 
+function tunnel_action(b, param)
+  local r = nil
+  print("Tunnel from " .. tostring(b) .. " [" .. param .. "]")
+
+  if tonumber(param)~=nil then
+    r = get_region_by_id(tonumber(param))
+  end
+  if r~=nil then
+    local units = tunnel_travelers(b)
+    for key, u in pairs(units) do
+      local rto = r
+      if r==nil then
+        rto = get_target(param)
+      end
+      if rto~=nil then
+        u.region = rto
+        print(" - teleported " .. tostring(u) .. " to " .. tostring(rto))
+      end
+    end
+  end
+  return 1 -- return 0 to destroy
+end
+
+function action(b, param)
+  print(b)
+  print(param)
+  return 1
+end
+
+function test_tunnels()
+  r = terraform(0, 0, "glacier")
+  b = add_building(r, "portal")
+  b:add_action("tunnel_action", "tnnL")
+  r2 = terraform(5, 5, "plain")
+  r2:set_key("tnnL", true)
+  process_orders()
+end
+
 loadscript("default.lua")
 run_scripts()
 -- go
 -- test_free()
 -- test_bmark()
 -- test_realloc()
-test_hse()
+-- test_hse()
+test_tunnels()
 -- test_md5()
 -- test_287()
 -- io.stdin:read("*line")