diff -r 31fcaa5375a1 -r e72987579514 src/engine.h
--- a/src/engine.h	Fri Aug 03 19:16:36 2007 +0000
+++ b/src/engine.h	Fri Aug 03 22:09:42 2007 +0000
@@ -45,7 +45,7 @@
 	                    //       kind of visual effect to generate for a vehicle (default, steam, diesel, electric).
 	                    //       Same goes for the callback result, which atm is only used to check if a wagon is powered.
 	byte shorten_factor;   ///< length on main map for this type is 8 - shorten_factor
-	byte tractive_effort; ///< Tractive effort coefficient
+	byte tractive_effort;  ///< Tractive effort coefficient
 	byte user_def_data;    ///< Property 0x25: "User-defined bit mask" Used only for (very few) NewGRF vehicles
 };
 
@@ -262,19 +262,7 @@
  * Engine Replacement stuff
  ************************************************************************/
 
-/**
- * Struct to store engine replacements. DO NOT USE outside of engine.c. Is
- * placed here so the only exception to this rule, the saveload code, can use
- * it.
- */
-struct EngineRenew {
-	EngineRenewID index;
-	EngineID from;
-	EngineID to;
-	EngineRenew *next;
-	GroupID group_id;
-};
-
+struct EngineRenew;
 /**
  * Memory pool for engine renew elements. DO NOT USE outside of engine.c. Is
  * placed here so the only exception to this rule, the saveload code, can use
@@ -283,19 +271,23 @@
 DECLARE_OLD_POOL(EngineRenew, EngineRenew, 3, 8000)
 
 /**
- * Check if a EngineRenew really exists.
+ * Struct to store engine replacements. DO NOT USE outside of engine.c. Is
+ * placed here so the only exception to this rule, the saveload code, can use
+ * it.
  */
-static inline bool IsValidEngineRenew(const EngineRenew *er)
-{
-	return er->from != INVALID_ENGINE;
-}
+struct EngineRenew : PoolItem<EngineRenew, EngineRenewID, &_EngineRenew_pool> {
+	EngineID from;
+	EngineID to;
+	EngineRenew *next;
+	GroupID group_id;
 
-static inline void DeleteEngineRenew(EngineRenew *er)
-{
-	er->from = INVALID_ENGINE;
-}
+	EngineRenew(EngineID from = INVALID_ENGINE, EngineID to = INVALID_ENGINE) : from(from), to(to), next(NULL) {}
+	~EngineRenew() { this->from = INVALID_ENGINE; }
 
-#define FOR_ALL_ENGINE_RENEWS_FROM(er, start) for (er = GetEngineRenew(start); er != NULL; er = (er->index + 1U < GetEngineRenewPoolSize()) ? GetEngineRenew(er->index + 1U) : NULL) if (er->from != INVALID_ENGINE) if (IsValidEngineRenew(er))
+	bool IsValid() const { return this->from != INVALID_ENGINE; }
+};
+
+#define FOR_ALL_ENGINE_RENEWS_FROM(er, start) for (er = GetEngineRenew(start); er != NULL; er = (er->index + 1U < GetEngineRenewPoolSize()) ? GetEngineRenew(er->index + 1U) : NULL) if (er->IsValid())
 #define FOR_ALL_ENGINE_RENEWS(er) FOR_ALL_ENGINE_RENEWS_FROM(er, 0)
 
 
@@ -309,7 +301,7 @@
  * @param  erl The renewlist for a given player.
  * @return The new renewlist for the player.
  */
-void RemoveAllEngineReplacement(EngineRenewList* erl);
+void RemoveAllEngineReplacement(EngineRenewList *erl);
 
 /**
  * Retrieve the engine replacement in a given renewlist for an original engine type.
@@ -328,7 +320,7 @@
  * @param flags The calling command flags.
  * @return 0 on success, CMD_ERROR on failure.
  */
-CommandCost AddEngineReplacement(EngineRenewList* erl, EngineID old_engine, EngineID new_engine, GroupID group, uint32 flags);
+CommandCost AddEngineReplacement(EngineRenewList *erl, EngineID old_engine, EngineID new_engine, GroupID group, uint32 flags);
 
 /**
  * Remove an engine replacement from a given renewlist.
@@ -337,7 +329,7 @@
  * @param flags The calling command flags.
  * @return 0 on success, CMD_ERROR on failure.
  */
-CommandCost RemoveEngineReplacement(EngineRenewList* erl, EngineID engine, GroupID group, uint32 flags);
+CommandCost RemoveEngineReplacement(EngineRenewList *erl, EngineID engine, GroupID group, uint32 flags);
 
 /** When an engine is made buildable or is removed from being buildable, add/remove it from the build/autoreplace lists
  * @param type The type of engine