--- common/unit.c.orig	Thu Jan 28 12:50:28 1999
+++ common/unit.c	Thu Jan 28 12:53:28 1999
@@ -669,24 +669,20 @@
   switch(activity)  {
   case ACTIVITY_POLLUTION:
     return unit_flag(punit->type, F_SETTLERS) && punit->moves_left &&
-           (ptile->special&S_POLLUTION) &&
-	   !is_unit_activity_on_tile(ACTIVITY_POLLUTION, punit->x, punit->y);
+           (ptile->special&S_POLLUTION);
 
   case ACTIVITY_ROAD:
     return unit_flag(punit->type, F_SETTLERS) && punit->moves_left &&
            !(ptile->special&S_ROAD) && ptile->terrain!=T_OCEAN &&
 	   (ptile->terrain!=T_RIVER || 
-	    get_invention(pplayer, A_BRIDGE)==TECH_KNOWN) &&
-	   !is_unit_activity_on_tile(ACTIVITY_ROAD, punit->x, punit->y);
+	    get_invention(pplayer, A_BRIDGE)==TECH_KNOWN);
 
   case ACTIVITY_MINE:
     return unit_flag(punit->type, F_SETTLERS) && punit->moves_left &&
-           type->mining_result!=T_LAST && !(ptile->special&S_MINE) &&
-	   !is_unit_activity_on_tile(ACTIVITY_MINE, punit->x, punit->y);
+           type->mining_result!=T_LAST && !(ptile->special&S_MINE);
 
   case ACTIVITY_IRRIGATE:
     return unit_flag(punit->type, F_SETTLERS) && punit->moves_left &&
-           !is_unit_activity_on_tile(ACTIVITY_IRRIGATE, punit->x, punit->y) &&
 	   !(ptile->special&S_IRRIGATION) &&
 	   ( (ptile->terrain==type->irrigation_result && 
 	      is_water_adjacent_to_tile(punit->x, punit->y)) ||
@@ -700,8 +696,7 @@
   case ACTIVITY_FORTRESS:
     return unit_flag(punit->type, F_SETTLERS) && punit->moves_left &&
            get_invention(pplayer, A_CONSTRUCTION) == TECH_KNOWN &&
-	   !(ptile->special&S_FORTRESS) && ptile->terrain!=T_OCEAN &&
-	   !is_unit_activity_on_tile(ACTIVITY_FORTRESS, punit->x, punit->y);
+	   !(ptile->special&S_FORTRESS) && ptile->terrain!=T_OCEAN;
 
   case ACTIVITY_SENTRY:
     return 1;
@@ -710,8 +705,7 @@
     /* if the tile has road, the terrain must be ok.. */
     return unit_flag(punit->type, F_SETTLERS) && punit->moves_left &&
            (ptile->special&S_ROAD) && !(ptile->special&S_RAILROAD) &&
-	   get_invention(&game.players[punit->owner], A_RAILROAD)==TECH_KNOWN &&
-	   !is_unit_activity_on_tile(ACTIVITY_RAILROAD, punit->x, punit->y);
+	   get_invention(&game.players[punit->owner], A_RAILROAD)==TECH_KNOWN;
 
   case ACTIVITY_PILLAGE:
     return is_ground_unit(punit) && punit->moves_left &&
--- server/unitfunc.c.orig	Thu Jan 28 06:33:06 1999
+++ server/unitfunc.c	Thu Jan 28 11:39:46 1999
@@ -1128,6 +1128,23 @@
 }
 
 /**************************************************************************
+  Calculate the total amount of activity performed by all units on a tile
+  for a given task.
+**************************************************************************/
+int total_activity (int x, int y, enum unit_activity act)
+{
+  struct tile *ptile;
+  int total = 0;
+
+  ptile = map_get_tile (x, y);
+  unit_list_iterate (ptile->units, punit)
+    if (punit->activity == act)
+      total += punit->activity_count;
+  unit_list_iterate_end;
+  return total;
+}
+
+/**************************************************************************
   progress settlers in their current tasks, 
   and units that is pillaging.
   also move units that is on a goto.
@@ -1157,47 +1174,73 @@
     set_unit_activity(punit, ACTIVITY_IDLE);
    }
 
-  if(punit->activity==ACTIVITY_POLLUTION && punit->activity_count>=3) {
-    map_clear_special(punit->x, punit->y, S_POLLUTION);
-    send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
-    set_unit_activity(punit, ACTIVITY_IDLE);
+  if(punit->activity==ACTIVITY_POLLUTION) {
+    if (total_activity (punit->x, punit->y, ACTIVITY_POLLUTION) >= 3) {
+      map_clear_special(punit->x, punit->y, S_POLLUTION);
+      send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
+      unit_list_iterate (map_get_tile (punit->x, punit->y)->units, punit2)
+        if (punit2->activity == ACTIVITY_POLLUTION)
+          set_unit_activity(punit2, ACTIVITY_IDLE);
+      unit_list_iterate_end;
+    }
   }
 
-  if(punit->activity==ACTIVITY_FORTRESS && punit->activity_count>=3) {
-    map_set_special(punit->x, punit->y, S_FORTRESS);
-    send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
-    set_unit_activity(punit, ACTIVITY_IDLE);
+  if(punit->activity==ACTIVITY_FORTRESS) {
+    if (total_activity (punit->x, punit->y, ACTIVITY_FORTRESS) >= 3) {
+      map_set_special(punit->x, punit->y, S_FORTRESS);
+      send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
+      unit_list_iterate (map_get_tile (punit->x, punit->y)->units, punit2)
+        if (punit2->activity == ACTIVITY_FORTRESS)
+          set_unit_activity(punit2, ACTIVITY_IDLE);
+      unit_list_iterate_end;
+    }
   }
   
-  if(punit->activity==ACTIVITY_IRRIGATE && 
-     punit->activity_count>=map_build_irrigation_time(punit->x, punit->y)) {
-    map_irrigate_tile(punit->x, punit->y);
-    send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
-    punit->activity=ACTIVITY_IDLE;
-    set_unit_activity(punit, ACTIVITY_IDLE);
+  if(punit->activity==ACTIVITY_IRRIGATE) {
+    if (total_activity (punit->x, punit->y, ACTIVITY_IRRIGATE) >=
+        map_build_irrigation_time(punit->x, punit->y)) {
+      map_irrigate_tile(punit->x, punit->y);
+      send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
+      unit_list_iterate (map_get_tile (punit->x, punit->y)->units, punit2)
+        if (punit2->activity == ACTIVITY_IRRIGATE)
+          set_unit_activity(punit2, ACTIVITY_IDLE);
+      unit_list_iterate_end;
+    }
   }
 
-  if(punit->activity==ACTIVITY_ROAD && 
-     punit->activity_count>map_build_road_time(punit->x, punit->y)) {
-    map_set_special(punit->x, punit->y, S_ROAD);
-    send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
-    punit->activity=ACTIVITY_IDLE;
-    set_unit_activity(punit, ACTIVITY_IDLE);
+  if(punit->activity==ACTIVITY_ROAD) {
+    if (total_activity (punit->x, punit->y, ACTIVITY_ROAD) >	/* not >= ? */
+        map_build_road_time(punit->x, punit->y)) {
+      map_set_special(punit->x, punit->y, S_ROAD);
+      send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
+      unit_list_iterate (map_get_tile (punit->x, punit->y)->units, punit2)
+        if (punit2->activity == ACTIVITY_ROAD)
+          set_unit_activity(punit2, ACTIVITY_IDLE);
+      unit_list_iterate_end;
+    }
   }
 
-  if(punit->activity==ACTIVITY_RAILROAD && punit->activity_count>=3) {
-    map_set_special(punit->x, punit->y, S_RAILROAD);
-    send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
-    punit->activity=ACTIVITY_IDLE;
-    handle_unit_activity_request(pplayer, punit, ACTIVITY_IDLE);
-    set_unit_activity(punit, ACTIVITY_IDLE);
+  if(punit->activity==ACTIVITY_RAILROAD) {
+    if (total_activity (punit->x, punit->x, ACTIVITY_RAILROAD) >= 3) {
+      map_set_special(punit->x, punit->y, S_RAILROAD);
+      send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
+      unit_list_iterate (map_get_tile (punit->x, punit->y)->units, punit2)
+        if (punit2->activity == ACTIVITY_RAILROAD)
+          set_unit_activity(punit2, ACTIVITY_IDLE);
+      unit_list_iterate_end;
+    }
   }
   
-  if(punit->activity==ACTIVITY_MINE && 
-     punit->activity_count>=map_build_mine_time(punit->x, punit->y)) {
-    map_mine_tile(punit->x, punit->y);
-    send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
-    set_unit_activity(punit, ACTIVITY_IDLE);
+  if(punit->activity==ACTIVITY_MINE) {
+    if (total_activity (punit->x, punit->y, ACTIVITY_MINE) >=
+        map_build_mine_time(punit->x, punit->y)) {
+      map_mine_tile(punit->x, punit->y);
+      send_tile_info(0, punit->x, punit->y, TILE_KNOWN);
+      unit_list_iterate (map_get_tile (punit->x, punit->y)->units, punit2)
+        if (punit2->activity == ACTIVITY_MINE)
+          set_unit_activity(punit2, ACTIVITY_IDLE);
+      unit_list_iterate_end;
+    }
   }
 
   if(punit->activity==ACTIVITY_GOTO) {