diff --git a/npf.c b/npf.c
index ab7cdb5a90..786fef609d 100644
--- a/npf.c
+++ b/npf.c
@@ -369,7 +369,10 @@ int32 NPFRailPathCost(AyStar* as, AyStarNode* current, OpenListNode* parent) {
 	cost += NPFSlopeCost(current);
 
 	/* Check for turns */
-	//TODO
+	if (current->direction != parent->path.node.direction)
+		cost += _patches.npf_rail_curve_penalty;
+	//TODO, with realistic acceleration, also the amount of straight track between
+	//      curves should be taken into account, as this affects the speed limit.
 
 	/* Check for occupied track */
 	//TODO
diff --git a/settings.c b/settings.c
index ebd2eea3cb..59ac388ed7 100644
--- a/settings.c
+++ b/settings.c
@@ -949,6 +949,7 @@ const SettingDesc patch_settings[] = {
 	*/
 	{"npf_rail_station_penalty",		SDT_UINT32, (void*)(1 * NPF_TILE_LENGTH),		&_patches.npf_rail_station_penalty, 		NULL},
 	{"npf_rail_slope_penalty",			SDT_UINT32, (void*)(1 * NPF_TILE_LENGTH),		&_patches.npf_rail_slope_penalty,				NULL},
+	{"npf_rail_curve_penalty",			SDT_UINT32, (void*)(1),		&_patches.npf_rail_curve_penalty,				NULL},
 
 	{NULL,									0,					NULL,					NULL,																						NULL}
 };
diff --git a/variables.h b/variables.h
index ecc525749c..3149f827b8 100644
--- a/variables.h
+++ b/variables.h
@@ -196,6 +196,7 @@ typedef struct Patches {
 	uint32 npf_rail_lastred_penalty; /* The penalty for when the last signal is red */
 	uint32 npf_rail_station_penalty; /* The penalty for station tiles */
 	uint32 npf_rail_slope_penalty; /* The penalty for sloping upwards */
+	uint32 npf_rail_curve_penalty; /* The penalty for curves */
 
 	bool population_in_label; // Show the population of a town in his label?
 } Patches;