diff --git a/src/misc/array.hpp b/src/misc/array.hpp
index 220082da5a..a88b6cbe9b 100644
--- a/src/misc/array.hpp
+++ b/src/misc/array.hpp
@@ -68,6 +68,19 @@ public:
 		const Titem& item   = sa [idx % Tblock_size];
 		return item;
 	}
+
+	template <typename D> void Dump(D &dmp) const
+	{
+		dmp.WriteLine("capacity = %d", Tcapacity);
+		int num_items = Size();
+		dmp.WriteLine("num_items = %d", num_items);
+		CStrA name;
+		for (int i = 0; i < num_items; i++) {
+			const Titem& item = (*this)[i];
+			name.Format("item[%d]", i);
+			dmp.WriteStructT(name.Data(), &item);
+		}
+	}
 };
 
 #endif /* ARRAY_HPP */
diff --git a/src/yapf/nodelist.hpp b/src/yapf/nodelist.hpp
index 000c36659a..a174d69d83 100644
--- a/src/yapf/nodelist.hpp
+++ b/src/yapf/nodelist.hpp
@@ -127,6 +127,11 @@ public:
 
 	FORCEINLINE int TotalCount() {return m_arr.Size();}
 	FORCEINLINE Titem_& ItemAt(int idx) {return m_arr[idx];}
+
+	template <class D> void Dump(D &dmp) const
+	{
+		dmp.WriteStructT("m_arr", &m_arr);
+	}
 };
 
 #endif /* NODELIST_HPP */
diff --git a/src/yapf/yapf.hpp b/src/yapf/yapf.hpp
index 4faff60b50..2e107b0522 100644
--- a/src/yapf/yapf.hpp
+++ b/src/yapf/yapf.hpp
@@ -78,6 +78,7 @@ typedef CPerfStartFake CPerfStart;
 #include "../misc/array.hpp"
 #include "../misc/hashtable.hpp"
 #include "../misc/binaryheap.hpp"
+#include "../misc/dbg_helpers.h"
 #include "nodelist.hpp"
 #include "follow_track.hpp"
 #include "yapf_base.hpp"
diff --git a/src/yapf/yapf_base.hpp b/src/yapf/yapf_base.hpp
index ecf3842133..43dd1793b9 100644
--- a/src/yapf/yapf_base.hpp
+++ b/src/yapf/yapf_base.hpp
@@ -280,6 +280,12 @@ public:
 
 	const Vehicle* GetVehicle() const {return m_veh;}
 
+	void DumpBase(DumpTarget &dmp) const
+	{
+		dmp.WriteStructT("m_nodes", &m_nodes);
+		dmp.WriteLine("m_num_steps = %d", m_num_steps);
+	}
+
 	// methods that should be implemented at derived class Types::Tpf (derived from CYapfBaseT)
 
 #if 0
diff --git a/src/yapf/yapf_node.hpp b/src/yapf/yapf_node.hpp
index 577a40b7dd..305e848a73 100644
--- a/src/yapf/yapf_node.hpp
+++ b/src/yapf/yapf_node.hpp
@@ -20,6 +20,13 @@ struct CYapfNodeKeyExitDir {
 
 	FORCEINLINE int CalcHash() const {return m_exitdir | (m_tile << 2);}
 	FORCEINLINE bool operator == (const CYapfNodeKeyExitDir& other) const {return (m_tile == other.m_tile) && (m_exitdir == other.m_exitdir);}
+
+	void Dump(DumpTarget &dmp) const
+	{
+		dmp.WriteTile("m_tile", m_tile);
+		dmp.WriteEnumT("m_td", m_td);
+		dmp.WriteEnumT("m_exitdir", m_exitdir);
+	}
 };
 
 struct CYapfNodeKeyTrackDir : public CYapfNodeKeyExitDir
@@ -57,6 +64,14 @@ struct CYapfNodeT {
 	FORCEINLINE int GetCost() {return m_cost;}
 	FORCEINLINE int GetCostEstimate() {return m_estimate;}
 	FORCEINLINE bool operator < (const Node& other) const {return m_estimate < other.m_estimate;}
+
+	void Dump(DumpTarget &dmp) const
+	{
+		dmp.WriteStructT("m_key", &m_key);
+		dmp.WriteStructT("m_parent", m_parent);
+		dmp.WriteLine("m_cost = %d", m_cost);
+		dmp.WriteLine("m_estimate = %d", m_estimate);
+	}
 };
 
 /** Yapf Node for ships */
diff --git a/src/yapf/yapf_node_rail.hpp b/src/yapf/yapf_node_rail.hpp
index 4097fc5053..59aa696f74 100644
--- a/src/yapf/yapf_node_rail.hpp
+++ b/src/yapf/yapf_node_rail.hpp
@@ -19,6 +19,12 @@ struct CYapfRailSegmentKey
 	FORCEINLINE int32 CalcHash() const {return m_value;}
 	FORCEINLINE TileIndex GetTile() const {return (TileIndex)(m_value >> 3);}
 	FORCEINLINE bool operator == (const CYapfRailSegmentKey& other) const {return m_value == other.m_value;}
+
+	void Dump(DumpTarget &dmp) const
+	{
+		dmp.WriteTile("tile", GetTile());
+		dmp.WriteEnumT("td", GetTrackdir());
+	}
 };
 
 /* Enum used in PfCalcCost() to see why was the segment closed. */
@@ -63,7 +69,7 @@ enum EndSegmentReasonBits {
 
 	/* Additional (composite) values. */
 
-	/* What reasons mean that the target can be fond and needs to be detected. */
+	/* What reasons mean that the target can be found and needs to be detected. */
 	ESRB_POSSIBLE_TARGET = ESRB_DEPOT | ESRB_WAYPOINT | ESRB_STATION,
 
 	/* What reasons can be stored back into cached segment. */
@@ -75,6 +81,19 @@ enum EndSegmentReasonBits {
 
 DECLARE_ENUM_AS_BIT_SET(EndSegmentReasonBits);
 
+inline CStrA ValueStr(EndSegmentReasonBits bits)
+{
+	static const char* end_segment_reason_names[] = {
+		"DEAD_END", "RAIL_TYPE", "INFINITE_LOOP", "SEGMENT_TOO_LONG", "CHOICE_FOLLOWS",
+		"DEPOT", "WAYPOINT", "STATION",
+		"PATH_TOO_LONG", "FIRST_TWO_WAY_RED", "LOOK_AHEAD_END", "TARGET_REACHED"
+	};
+
+	CStrA out;
+	out.Format("0x%04X (%s)", bits, ComposeNameT(bits, end_segment_reason_names, "UNK", ESRB_NONE, "NONE").Data());
+	return out.Transfer();
+}
+
 /** cached segment cost for rail YAPF */
 struct CYapfRailSegment
 {
@@ -104,6 +123,17 @@ struct CYapfRailSegment
 	FORCEINLINE TileIndex GetTile() const {return m_key.GetTile();}
 	FORCEINLINE CYapfRailSegment* GetHashNext() {return m_hash_next;}
 	FORCEINLINE void SetHashNext(CYapfRailSegment* next) {m_hash_next = next;}
+
+	void Dump(DumpTarget &dmp) const
+	{
+		dmp.WriteStructT("m_key", &m_key);
+		dmp.WriteTile("m_last_tile", m_last_tile);
+		dmp.WriteEnumT("m_last_td", m_last_td);
+		dmp.WriteLine("m_cost = %d", m_cost);
+		dmp.WriteTile("m_last_signal_tile", m_last_signal_tile);
+		dmp.WriteEnumT("m_last_signal_td", m_last_signal_td);
+		dmp.WriteEnumT("m_end_segment_reason", m_end_segment_reason);
+	}
 };
 
 /** Yapf Node for rail YAPF */
@@ -145,6 +175,17 @@ struct CYapfRailNodeT
 	FORCEINLINE TileIndex GetLastTile() const {assert(m_segment != NULL); return m_segment->m_last_tile;}
 	FORCEINLINE Trackdir GetLastTrackdir() const {assert(m_segment != NULL); return m_segment->m_last_td;}
 	FORCEINLINE void SetLastTileTrackdir(TileIndex tile, Trackdir td) {assert(m_segment != NULL); m_segment->m_last_tile = tile; m_segment->m_last_td = td;}
+
+	void Dump(DumpTarget &dmp) const
+	{
+		base::Dump(dmp);
+		dmp.WriteStructT("m_segment", m_segment);
+		dmp.WriteLine("m_num_signals_passed = %d", m_num_signals_passed);
+		dmp.WriteLine("m_targed_seen = %s", flags_u.flags_s.m_targed_seen ? "Yes" : "No");
+		dmp.WriteLine("m_choice_seen = %s", flags_u.flags_s.m_choice_seen ? "Yes" : "No");
+		dmp.WriteLine("m_last_signal_was_red = %s", flags_u.flags_s.m_last_signal_was_red ? "Yes" : "No");
+		dmp.WriteEnumT("m_last_red_signal_type", m_last_red_signal_type);
+	}
 };
 
 // now define two major node types (that differ by key type)
diff --git a/src/yapf/yapf_rail.cpp b/src/yapf/yapf_rail.cpp
index 1437356f48..964993bf4d 100644
--- a/src/yapf/yapf_rail.cpp
+++ b/src/yapf/yapf_rail.cpp
@@ -132,6 +132,15 @@ public:
 		Trackdir result2 = pf2.ChooseRailTrack(v, tile, enterdir, tracks, path_not_found);
 		if (result1 != result2) {
 			DEBUG(yapf, 0, "CACHE ERROR: ChooseRailTrack() = [%d, %d]", result1, result2);
+			DumpTarget dmp1, dmp2;
+			pf1.DumpBase(dmp1);
+			pf2.DumpBase(dmp2);
+			FILE *f1 = fopen("C:\\yapf1.txt", "wt");
+			FILE *f2 = fopen("C:\\yapf2.txt", "wt");
+			fwrite(dmp1.m_out.Data(), 1, dmp1.m_out.Size(), f1);
+			fwrite(dmp2.m_out.Data(), 1, dmp2.m_out.Size(), f2);
+			fclose(f1);
+			fclose(f2);
 		}
 #endif