(svn r3697) Rename DIAG1/DIAG2 to X resp. Y as this conveys a bit better in which direction a pieces of rail goes

8 files changed, 108 insertions, 110 deletions

diff --git a/pathfind.c b/pathfind.c
index 6da852771..9ece86052 100644
--- a/pathfind.c
+++ b/pathfind.c
@@ -623,18 +623,18 @@ static bool NtpCheck(NewTrackPathFinder *tpf, TileIndex tile, uint dir, uint len
 
 static const uint16 _is_upwards_slope[15] = {
 	0, // no tileh
-	(1 << TRACKDIR_DIAG1_SW) | (1 << TRACKDIR_DIAG2_NW), // 1
-	(1 << TRACKDIR_DIAG1_SW) | (1 << TRACKDIR_DIAG2_SE), // 2
-	(1 << TRACKDIR_DIAG1_SW), // 3
-	(1 << TRACKDIR_DIAG1_NE) | (1 << TRACKDIR_DIAG2_SE), // 4
+	(1 << TRACKDIR_X_SW) | (1 << TRACKDIR_Y_NW), // 1
+	(1 << TRACKDIR_X_SW) | (1 << TRACKDIR_Y_SE), // 2
+	(1 << TRACKDIR_X_SW), // 3
+	(1 << TRACKDIR_X_NE) | (1 << TRACKDIR_Y_SE), // 4
 	0, // 5
-	(1 << TRACKDIR_DIAG2_SE), // 6
+	(1 << TRACKDIR_Y_SE), // 6
 	0, // 7
-	(1 << TRACKDIR_DIAG1_NE) | (1 << TRACKDIR_DIAG2_NW), // 8,
-	(1 << TRACKDIR_DIAG2_NW), // 9
+	(1 << TRACKDIR_X_NE) | (1 << TRACKDIR_Y_NW), // 8,
+	(1 << TRACKDIR_Y_NW), // 9
 	0, //10
 	0, //11,
-	(1 << TRACKDIR_DIAG1_NE), //12
+	(1 << TRACKDIR_X_NE), //12
 	0, //13
 	0, //14
 };
diff --git a/rail.c b/rail.c
index 7435411b2..286bf3e49 100644
--- a/rail.c
+++ b/rail.c
@@ -30,21 +30,21 @@ const byte _signal_on_track[] = {
  * track entering in this direction (including those making 90 degree turns)
  */
 const TrackdirBits _exitdir_reaches_trackdirs[] = {
-	TRACKDIR_BIT_DIAG1_NE | TRACKDIR_BIT_LOWER_E | TRACKDIR_BIT_LEFT_N,  /* DIAGDIR_NE */
-	TRACKDIR_BIT_DIAG2_SE | TRACKDIR_BIT_LEFT_S  | TRACKDIR_BIT_UPPER_E, /* DIAGDIR_SE */
-	TRACKDIR_BIT_DIAG1_SW | TRACKDIR_BIT_UPPER_W | TRACKDIR_BIT_RIGHT_S, /* DIAGDIR_SW */
-	TRACKDIR_BIT_DIAG2_NW | TRACKDIR_BIT_RIGHT_N | TRACKDIR_BIT_LOWER_W  /* DIAGDIR_NW */
+	TRACKDIR_BIT_X_NE | TRACKDIR_BIT_LOWER_E | TRACKDIR_BIT_LEFT_N,  /* DIAGDIR_NE */
+	TRACKDIR_BIT_Y_SE | TRACKDIR_BIT_LEFT_S  | TRACKDIR_BIT_UPPER_E, /* DIAGDIR_SE */
+	TRACKDIR_BIT_X_SW | TRACKDIR_BIT_UPPER_W | TRACKDIR_BIT_RIGHT_S, /* DIAGDIR_SW */
+	TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_RIGHT_N | TRACKDIR_BIT_LOWER_W  /* DIAGDIR_NW */
 };
 
 const Trackdir _next_trackdir[] = {
-	TRACKDIR_DIAG1_NE,  TRACKDIR_DIAG2_SE,  TRACKDIR_LOWER_E, TRACKDIR_UPPER_E, TRACKDIR_RIGHT_S, TRACKDIR_LEFT_S, INVALID_TRACKDIR, INVALID_TRACKDIR,
-	TRACKDIR_DIAG1_SW,  TRACKDIR_DIAG2_NW,  TRACKDIR_LOWER_W, TRACKDIR_UPPER_W, TRACKDIR_RIGHT_N, TRACKDIR_LEFT_N
+	TRACKDIR_X_NE,  TRACKDIR_Y_SE,  TRACKDIR_LOWER_E, TRACKDIR_UPPER_E, TRACKDIR_RIGHT_S, TRACKDIR_LEFT_S, INVALID_TRACKDIR, INVALID_TRACKDIR,
+	TRACKDIR_X_SW,  TRACKDIR_Y_NW,  TRACKDIR_LOWER_W, TRACKDIR_UPPER_W, TRACKDIR_RIGHT_N, TRACKDIR_LEFT_N
 };
 
 /* Maps a trackdir to all trackdirs that make 90 deg turns with it. */
 const TrackdirBits _track_crosses_trackdirs[] = {
-	TRACKDIR_BIT_DIAG2_SE | TRACKDIR_BIT_DIAG2_NW,                                               /* TRACK_DIAG1 */
-	TRACKDIR_BIT_DIAG1_NE | TRACKDIR_BIT_DIAG1_SW,                                               /* TRACK_DIAG2 */
+	TRACKDIR_BIT_Y_SE     | TRACKDIR_BIT_Y_NW,                                                   /* TRACK_X     */
+	TRACKDIR_BIT_X_NE     | TRACKDIR_BIT_X_SW,                                                   /* TRACK_Y     */
 	TRACKDIR_BIT_RIGHT_N  | TRACKDIR_BIT_RIGHT_S  | TRACKDIR_BIT_LEFT_N  | TRACKDIR_BIT_LEFT_S,  /* TRACK_UPPER */
 	TRACKDIR_BIT_RIGHT_N  | TRACKDIR_BIT_RIGHT_S  | TRACKDIR_BIT_LEFT_N  | TRACKDIR_BIT_LEFT_S,  /* TRACK_LOWER */
 	TRACKDIR_BIT_UPPER_W  | TRACKDIR_BIT_UPPER_E  | TRACKDIR_BIT_LOWER_W | TRACKDIR_BIT_LOWER_E, /* TRACK_LEFT  */
@@ -53,8 +53,8 @@ const TrackdirBits _track_crosses_trackdirs[] = {
 
 /* Maps a track to all tracks that make 90 deg turns with it. */
 const TrackBits _track_crosses_tracks[] = {
-	TRACK_BIT_DIAG2,                   /* TRACK_DIAG1 */
-	TRACK_BIT_DIAG1,                   /* TRACK_DIAG2 */
+	TRACK_BIT_Y,                       /* TRACK_X     */
+	TRACK_BIT_X,                       /* TRACK_Y     */
 	TRACK_BIT_LEFT  | TRACK_BIT_RIGHT, /* TRACK_UPPER */
 	TRACK_BIT_LEFT  | TRACK_BIT_RIGHT, /* TRACK_LOWER */
 	TRACK_BIT_UPPER | TRACK_BIT_LOWER, /* TRACK_LEFT  */
@@ -69,8 +69,8 @@ const DiagDirection _trackdir_to_exitdir[] = {
 };
 
 const Trackdir _track_exitdir_to_trackdir[][DIAGDIR_END] = {
-	{TRACKDIR_DIAG1_NE, INVALID_TRACKDIR,  TRACKDIR_DIAG1_SW, INVALID_TRACKDIR},
-	{INVALID_TRACKDIR,  TRACKDIR_DIAG2_SE, INVALID_TRACKDIR,  TRACKDIR_DIAG2_NW},
+	{TRACKDIR_X_NE,     INVALID_TRACKDIR,  TRACKDIR_X_SW,     INVALID_TRACKDIR},
+	{INVALID_TRACKDIR,  TRACKDIR_Y_SE,     INVALID_TRACKDIR,  TRACKDIR_Y_NW},
 	{TRACKDIR_UPPER_E,  INVALID_TRACKDIR,  INVALID_TRACKDIR,  TRACKDIR_UPPER_W},
 	{INVALID_TRACKDIR,  TRACKDIR_LOWER_E,  TRACKDIR_LOWER_W,  INVALID_TRACKDIR},
 	{INVALID_TRACKDIR,  INVALID_TRACKDIR,  TRACKDIR_LEFT_S,   TRACKDIR_LEFT_N},
@@ -78,8 +78,8 @@ const Trackdir _track_exitdir_to_trackdir[][DIAGDIR_END] = {
 };
 
 const Trackdir _track_enterdir_to_trackdir[][DIAGDIR_END] = { // TODO: replace magic with enums
-	{TRACKDIR_DIAG1_NE, INVALID_TRACKDIR,  TRACKDIR_DIAG1_SW, INVALID_TRACKDIR},
-	{INVALID_TRACKDIR,  TRACKDIR_DIAG2_SE, INVALID_TRACKDIR,  TRACKDIR_DIAG2_NW},
+	{TRACKDIR_X_NE,     INVALID_TRACKDIR,  TRACKDIR_X_SW,     INVALID_TRACKDIR},
+	{INVALID_TRACKDIR,  TRACKDIR_Y_SE,     INVALID_TRACKDIR,  TRACKDIR_Y_NW},
 	{INVALID_TRACKDIR,  TRACKDIR_UPPER_E,  TRACKDIR_UPPER_W,  INVALID_TRACKDIR},
 	{TRACKDIR_LOWER_E,  INVALID_TRACKDIR,  INVALID_TRACKDIR,  TRACKDIR_LOWER_W},
 	{TRACKDIR_LEFT_N,   TRACKDIR_LEFT_S,   INVALID_TRACKDIR,  INVALID_TRACKDIR},
@@ -87,8 +87,8 @@ const Trackdir _track_enterdir_to_trackdir[][DIAGDIR_END] = { // TODO: replace m
 };
 
 const Trackdir _track_direction_to_trackdir[][DIR_END] = {
-	{INVALID_TRACKDIR, TRACKDIR_DIAG1_NE, INVALID_TRACKDIR, INVALID_TRACKDIR,  INVALID_TRACKDIR, TRACKDIR_DIAG1_SW, INVALID_TRACKDIR, INVALID_TRACKDIR},
-	{INVALID_TRACKDIR, INVALID_TRACKDIR,  INVALID_TRACKDIR, TRACKDIR_DIAG2_SE, INVALID_TRACKDIR, INVALID_TRACKDIR,  INVALID_TRACKDIR, TRACKDIR_DIAG2_NW},
+	{INVALID_TRACKDIR, TRACKDIR_X_NE,     INVALID_TRACKDIR, INVALID_TRACKDIR,  INVALID_TRACKDIR, TRACKDIR_X_SW,     INVALID_TRACKDIR, INVALID_TRACKDIR},
+	{INVALID_TRACKDIR, INVALID_TRACKDIR,  INVALID_TRACKDIR, TRACKDIR_Y_SE,     INVALID_TRACKDIR, INVALID_TRACKDIR,  INVALID_TRACKDIR, TRACKDIR_Y_NW},
 	{INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_UPPER_E, INVALID_TRACKDIR,  INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_UPPER_W, INVALID_TRACKDIR},
 	{INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_LOWER_E, INVALID_TRACKDIR,  INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_LOWER_W, INVALID_TRACKDIR},
 	{TRACKDIR_LEFT_N,  INVALID_TRACKDIR,  INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_LEFT_S,  INVALID_TRACKDIR,  INVALID_TRACKDIR, INVALID_TRACKDIR},
@@ -96,7 +96,7 @@ const Trackdir _track_direction_to_trackdir[][DIR_END] = {
 };
 
 const Trackdir _dir_to_diag_trackdir[] = {
-	TRACKDIR_DIAG1_NE, TRACKDIR_DIAG2_SE, TRACKDIR_DIAG1_SW, TRACKDIR_DIAG2_NW,
+	TRACKDIR_X_NE, TRACKDIR_Y_SE, TRACKDIR_X_SW, TRACKDIR_Y_NW,
 };
 
 const DiagDirection _reverse_diagdir[] = {
@@ -104,8 +104,8 @@ const DiagDirection _reverse_diagdir[] = {
 };
 
 const Trackdir _reverse_trackdir[] = {
-	TRACKDIR_DIAG1_SW, TRACKDIR_DIAG2_NW, TRACKDIR_UPPER_W, TRACKDIR_LOWER_W, TRACKDIR_LEFT_N, TRACKDIR_RIGHT_N, INVALID_TRACKDIR, INVALID_TRACKDIR,
-	TRACKDIR_DIAG1_NE, TRACKDIR_DIAG2_SE, TRACKDIR_UPPER_E, TRACKDIR_LOWER_E, TRACKDIR_LEFT_S, TRACKDIR_RIGHT_S
+	TRACKDIR_X_SW, TRACKDIR_Y_NW, TRACKDIR_UPPER_W, TRACKDIR_LOWER_W, TRACKDIR_LEFT_N, TRACKDIR_RIGHT_N, INVALID_TRACKDIR, INVALID_TRACKDIR,
+	TRACKDIR_X_NE, TRACKDIR_Y_SE, TRACKDIR_UPPER_E, TRACKDIR_LOWER_E, TRACKDIR_LEFT_S, TRACKDIR_RIGHT_S
 };
 
 RailType GetTileRailType(TileIndex tile, Trackdir trackdir)
diff --git a/rail.h b/rail.h
index 9938bdb7f..794a9fe9a 100644
--- a/rail.h
+++ b/rail.h
@@ -67,8 +67,8 @@ enum {
 /** These are used to specify a single track. Can be translated to a trackbit
  * with TrackToTrackbit */
 typedef enum Tracks {
-	TRACK_DIAG1 = 0,
-	TRACK_DIAG2 = 1,
+	TRACK_X     = 0,
+	TRACK_Y     = 1,
 	TRACK_UPPER = 2,
 	TRACK_LOWER = 3,
 	TRACK_LEFT  = 4,
@@ -79,8 +79,8 @@ typedef enum Tracks {
 
 /** These are the bitfield variants of the above */
 typedef enum TrackBits {
-	TRACK_BIT_DIAG1 = 1U,    // 0
-	TRACK_BIT_DIAG2 = 2U,    // 1
+	TRACK_BIT_X     = 1U,    // 0
+	TRACK_BIT_Y     = 2U,    // 1
 	TRACK_BIT_UPPER = 4U,    // 2
 	TRACK_BIT_LOWER = 8U,    // 3
 	TRACK_BIT_LEFT  = 16U,   // 4
@@ -91,16 +91,16 @@ typedef enum TrackBits {
 /** These are a combination of tracks and directions. Values are 0-5 in one
 direction (corresponding to the Track enum) and 8-13 in the other direction. */
 typedef enum Trackdirs {
-	TRACKDIR_DIAG1_NE = 0,
-	TRACKDIR_DIAG2_SE = 1,
+	TRACKDIR_X_NE = 0,
+	TRACKDIR_Y_SE = 1,
 	TRACKDIR_UPPER_E  = 2,
 	TRACKDIR_LOWER_E  = 3,
 	TRACKDIR_LEFT_S   = 4,
 	TRACKDIR_RIGHT_S  = 5,
 	/* Note the two missing values here. This enables trackdir -> track
 	 * conversion by doing (trackdir & 7) */
-	TRACKDIR_DIAG1_SW = 8,
-	TRACKDIR_DIAG2_NW = 9,
+	TRACKDIR_X_SW = 8,
+	TRACKDIR_Y_NW = 9,
 	TRACKDIR_UPPER_W  = 10,
 	TRACKDIR_LOWER_W  = 11,
 	TRACKDIR_LEFT_N   = 12,
@@ -112,15 +112,15 @@ typedef enum Trackdirs {
 /** These are a combination of tracks and directions. Values are 0-5 in one
 direction (corresponding to the Track enum) and 8-13 in the other direction. */
 typedef enum TrackdirBits {
-	TRACKDIR_BIT_DIAG1_NE = 0x1,
-	TRACKDIR_BIT_DIAG2_SE = 0x2,
+	TRACKDIR_BIT_X_NE     = 0x1,
+	TRACKDIR_BIT_Y_SE     = 0x2,
 	TRACKDIR_BIT_UPPER_E  = 0x4,
 	TRACKDIR_BIT_LOWER_E  = 0x8,
 	TRACKDIR_BIT_LEFT_S   = 0x10,
 	TRACKDIR_BIT_RIGHT_S  = 0x20,
 	/* Again, note the two missing values here. This enables trackdir -> track conversion by doing (trackdir & 0xFF) */
-	TRACKDIR_BIT_DIAG1_SW = 0x0100,
-	TRACKDIR_BIT_DIAG2_NW = 0x0200,
+	TRACKDIR_BIT_X_SW     = 0x0100,
+	TRACKDIR_BIT_Y_NW     = 0x0200,
 	TRACKDIR_BIT_UPPER_W  = 0x0400,
 	TRACKDIR_BIT_LOWER_W  = 0x0800,
 	TRACKDIR_BIT_LEFT_N   = 0x1000,
@@ -481,7 +481,7 @@ static inline DiagDirection DirToDiagdir(Direction dir) {
 }
 
 /* Checks if a given Track is diagonal */
-static inline bool IsDiagonalTrack(Track track) { return (track == TRACK_DIAG1) || (track == TRACK_DIAG2); }
+static inline bool IsDiagonalTrack(Track track) { return (track == TRACK_X) || (track == TRACK_Y); }
 
 /* Checks if a given Trackdir is diagonal. */
 static inline bool IsDiagonalTrackdir(Trackdir trackdir) { return IsDiagonalTrack(TrackdirToTrack(trackdir)); }
@@ -586,10 +586,10 @@ static inline TransportType GetCrossingTransportType(TileIndex tile, Track track
 {
 	/* XXX: Nicer way to write this? */
 	switch (track) {
-		/* When map5 bit 3 is set, the road runs in the y direction (DIAG2) */
-		case TRACK_DIAG1:
+		/* When map5 bit 3 is set, the road runs in the y direction */
+		case TRACK_X:
 			return (HASBIT(_m[tile].m5, 3) ? TRANSPORT_RAIL : TRANSPORT_ROAD);
-		case TRACK_DIAG2:
+		case TRACK_Y:
 			return (HASBIT(_m[tile].m5, 3) ? TRANSPORT_ROAD : TRANSPORT_RAIL);
 		default:
 			assert(0);
diff --git a/rail_cmd.c b/rail_cmd.c
index eb98ce8b8..6b33d4d67 100644
--- a/rail_cmd.c
+++ b/rail_cmd.c
@@ -134,22 +134,22 @@ static const byte _valid_tileh_slopes[4][15] = {
 
 // set of normal ones
 {
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
 	TRACK_BIT_RIGHT,
 	TRACK_BIT_UPPER,
-	TRACK_BIT_DIAG1,
+	TRACK_BIT_X,
 
 	TRACK_BIT_LEFT,
 	0,
-	TRACK_BIT_DIAG2,
+	TRACK_BIT_Y,
 	TRACK_BIT_LOWER,
 
 	TRACK_BIT_LOWER,
-	TRACK_BIT_DIAG2,
+	TRACK_BIT_Y,
 	0,
 	TRACK_BIT_LEFT,
 
-	TRACK_BIT_DIAG1,
+	TRACK_BIT_X,
 	TRACK_BIT_UPPER,
 	TRACK_BIT_RIGHT,
 },
@@ -159,21 +159,21 @@ static const byte _valid_tileh_slopes[4][15] = {
 	0,
 	TRACK_BIT_LEFT,
 	TRACK_BIT_LOWER,
-	TRACK_BIT_DIAG2 | TRACK_BIT_LOWER | TRACK_BIT_LEFT,
+	TRACK_BIT_Y | TRACK_BIT_LOWER | TRACK_BIT_LEFT,
 
 	TRACK_BIT_RIGHT,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
-	TRACK_BIT_DIAG1 | TRACK_BIT_LOWER | TRACK_BIT_RIGHT,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X | TRACK_BIT_LOWER | TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
 
 	TRACK_BIT_UPPER,
-	TRACK_BIT_DIAG1 | TRACK_BIT_UPPER | TRACK_BIT_LEFT,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X | TRACK_BIT_UPPER | TRACK_BIT_LEFT,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
 
-	TRACK_BIT_DIAG2 | TRACK_BIT_UPPER | TRACK_BIT_RIGHT,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_Y | TRACK_BIT_UPPER | TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
 },
 
 // allowed rail on coast tile
@@ -181,21 +181,21 @@ static const byte _valid_tileh_slopes[4][15] = {
 	0,
 	TRACK_BIT_LEFT,
 	TRACK_BIT_LOWER,
-	TRACK_BIT_DIAG2|TRACK_BIT_LEFT|TRACK_BIT_LOWER,
+	TRACK_BIT_Y|TRACK_BIT_LEFT|TRACK_BIT_LOWER,
 
 	TRACK_BIT_RIGHT,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
-	TRACK_BIT_DIAG1|TRACK_BIT_RIGHT|TRACK_BIT_LOWER,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_RIGHT|TRACK_BIT_LOWER,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
 
 	TRACK_BIT_UPPER,
-	TRACK_BIT_DIAG1|TRACK_BIT_LEFT|TRACK_BIT_UPPER,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_LEFT|TRACK_BIT_UPPER,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
 
-	TRACK_BIT_DIAG2|TRACK_BIT_RIGHT|TRACK_BIT_UPPER,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
-	TRACK_BIT_DIAG1|TRACK_BIT_DIAG2|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_Y|TRACK_BIT_RIGHT|TRACK_BIT_UPPER,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
+	TRACK_BIT_X|TRACK_BIT_Y|TRACK_BIT_UPPER|TRACK_BIT_LOWER|TRACK_BIT_LEFT|TRACK_BIT_RIGHT,
 	},
 
 	// valid railway crossings on slopes
@@ -224,8 +224,8 @@ uint GetRailFoundation(uint tileh, uint bits)
 				(i += 2, tileh == 4) ||
 				(i += 2, tileh == 8)
 			) && (
-				bits == TRACK_BIT_DIAG1 ||
-				(i++, bits == TRACK_BIT_DIAG2)
+				bits == TRACK_BIT_X ||
+				(i++, bits == TRACK_BIT_Y)
 			)) {
 		return i + 15;
 	} else {
@@ -251,7 +251,7 @@ static uint32 CheckRailSlope(uint tileh, TrackBits rail_bits, TrackBits existing
 			return 0;
 
 		if ((~_valid_tileh_slopes[1][tileh] & rail_bits) == 0 || ( // whole tile is leveled up
-					(rail_bits == TRACK_BIT_DIAG1 || rail_bits == TRACK_BIT_DIAG2) &&
+					(rail_bits == TRACK_BIT_X || rail_bits == TRACK_BIT_Y) &&
 					(tileh == 1 || tileh == 2 || tileh == 4 || tileh == 8)
 				)) { // partly up
 			if (existing != 0) {
@@ -296,7 +296,7 @@ int32 CmdBuildSingleRail(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 	switch (GetTileType(tile)) {
 		case MP_TUNNELBRIDGE:
 			if ((m5 & 0xC0) != 0xC0 || // not bridge middle part?
-					(m5 & 0x01 ? TRACK_BIT_DIAG1 : TRACK_BIT_DIAG2) != trackbit) { // wrong direction?
+					(m5 & 0x01 ? TRACK_BIT_X : TRACK_BIT_Y) != trackbit) { // wrong direction?
 				// Get detailed error message
 				return DoCommandByTile(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 			}
@@ -351,16 +351,16 @@ int32 CmdBuildSingleRail(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 			if (!EnsureNoVehicle(tile)) return CMD_ERROR;
 
 			if (GetRoadType(tile) == ROAD_NORMAL && (
-						(track == TRACK_DIAG1 && m5 == ROAD_Y) ||
-						(track == TRACK_DIAG2 && m5 == ROAD_X) // correct direction?
+						(track == TRACK_X && m5 == ROAD_Y) ||
+						(track == TRACK_Y && m5 == ROAD_X) // correct direction?
 					)) {
 				if (flags & DC_EXEC) {
-					MakeRoadCrossing(tile, GetTileOwner(tile), _current_player, (track == TRACK_DIAG1 ? AXIS_Y : AXIS_X), p1, _m[tile].m2);
+					MakeRoadCrossing(tile, GetTileOwner(tile), _current_player, (track == TRACK_X ? AXIS_Y : AXIS_X), p1, _m[tile].m2);
 				}
 				break;
 			}
 
-			if (IsLevelCrossing(tile) && (m5 & 0x08 ? TRACK_DIAG1 : TRACK_DIAG2) == track)
+			if (IsLevelCrossing(tile) && (m5 & 0x08 ? TRACK_X : TRACK_Y) == track)
 				return_cmd_error(STR_1007_ALREADY_BUILT);
 			/* FALLTHROUGH */
 
@@ -423,7 +423,7 @@ int32 CmdRemoveSingleRail(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 			if ((_m[tile].m5 & 0xF8) != 0xE0)
 				return CMD_ERROR;
 
-			if ((_m[tile].m5 & 1 ? TRACK_BIT_DIAG1 : TRACK_BIT_DIAG2) != trackbit)
+			if ((_m[tile].m5 & 1 ? TRACK_BIT_X : TRACK_BIT_Y) != trackbit)
 				return CMD_ERROR;
 
 			if (!(flags & DC_EXEC))
@@ -440,12 +440,10 @@ int32 CmdRemoveSingleRail(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 
 			/* This is a crossing, let's check if the direction is correct */
 			if (_m[tile].m5 & 8) {
-				if (track != TRACK_DIAG1)
-					return CMD_ERROR;
+				if (track != TRACK_X) return CMD_ERROR;
 				bits = ROAD_Y;
 			} else {
-				if (track != TRACK_DIAG2)
-					return CMD_ERROR;
+				if (track != TRACK_Y) return CMD_ERROR;
 				bits = ROAD_X;
 			}
 
@@ -1072,8 +1070,8 @@ static int32 ClearTile_Track(TileIndex tile, byte flags)
 	switch (GetRailTileType(tile)) {
 		/* XXX: Why the fuck do we remove these thow signals first? */
 		case RAIL_TYPE_SIGNALS:
-			if (HasSignalOnTrack(tile, TRACK_DIAG1)) {
-				ret = DoCommandByTile(tile, TRACK_DIAG1, 0, flags, CMD_REMOVE_SIGNALS);
+			if (HasSignalOnTrack(tile, TRACK_X)) {
+				ret = DoCommandByTile(tile, TRACK_X, 0, flags, CMD_REMOVE_SIGNALS);
 				if (CmdFailed(ret)) return CMD_ERROR;
 				cost += ret;
 			}
@@ -1305,22 +1303,22 @@ static void DrawTrackBits(TileInfo* ti, TrackBits track, bool earth, bool snow,
 	bool junction = false;
 
 	// Select the sprite to use.
-	(image = rti->base_sprites.track_y, track == TRACK_BIT_DIAG2) ||
-	(image++,                           track == TRACK_BIT_DIAG1) ||
+	(image = rti->base_sprites.track_y, track == TRACK_BIT_Y) ||
+	(image++,                           track == TRACK_BIT_X) ||
 	(image++,                           track == TRACK_BIT_UPPER) ||
 	(image++,                           track == TRACK_BIT_LOWER) ||
 	(image++,                           track == TRACK_BIT_RIGHT) ||
 	(image++,                           track == TRACK_BIT_LEFT) ||
-	(image++,                           track == (TRACK_BIT_DIAG1 | TRACK_BIT_DIAG2)) ||
+	(image++,                           track == (TRACK_BIT_X | TRACK_BIT_Y)) ||
 
 	(image = rti->base_sprites.track_ns, track == (TRACK_BIT_UPPER | TRACK_BIT_LOWER)) ||
 	(image++,                            track == (TRACK_BIT_LEFT | TRACK_BIT_RIGHT)) ||
 
 	(junction = true, false) ||
-	(image = rti->base_sprites.ground, !(track & (TRACK_BIT_RIGHT | TRACK_BIT_UPPER | TRACK_BIT_DIAG1))) ||
-	(image++,                          !(track & (TRACK_BIT_LEFT | TRACK_BIT_LOWER | TRACK_BIT_DIAG1))) ||
-	(image++,                          !(track & (TRACK_BIT_LEFT | TRACK_BIT_UPPER | TRACK_BIT_DIAG2))) ||
-	(image++,                          !(track & (TRACK_BIT_RIGHT | TRACK_BIT_LOWER | TRACK_BIT_DIAG2))) ||
+	(image = rti->base_sprites.ground, !(track & (TRACK_BIT_RIGHT | TRACK_BIT_UPPER | TRACK_BIT_X))) ||
+	(image++,                          !(track & (TRACK_BIT_LEFT | TRACK_BIT_LOWER | TRACK_BIT_X))) ||
+	(image++,                          !(track & (TRACK_BIT_LEFT | TRACK_BIT_UPPER | TRACK_BIT_Y))) ||
+	(image++,                          !(track & (TRACK_BIT_RIGHT | TRACK_BIT_LOWER | TRACK_BIT_Y))) ||
 	(image++, true);
 
 	if (ti->tileh != 0) {
@@ -1351,8 +1349,8 @@ static void DrawTrackBits(TileInfo* ti, TrackBits track, bool earth, bool snow,
 
 	// Draw track pieces individually for junction tiles
 	if (junction) {
-		if (track & TRACK_BIT_DIAG1) DrawGroundSprite(rti->base_sprites.single_y);
-		if (track & TRACK_BIT_DIAG2) DrawGroundSprite(rti->base_sprites.single_x);
+		if (track & TRACK_BIT_X)     DrawGroundSprite(rti->base_sprites.single_y);
+		if (track & TRACK_BIT_Y)     DrawGroundSprite(rti->base_sprites.single_x);
 		if (track & TRACK_BIT_UPPER) DrawGroundSprite(rti->base_sprites.single_n);
 		if (track & TRACK_BIT_LOWER) DrawGroundSprite(rti->base_sprites.single_s);
 		if (track & TRACK_BIT_LEFT)  DrawGroundSprite(rti->base_sprites.single_w);
@@ -1392,8 +1390,8 @@ static void DrawTile_Track(TileInfo *ti)
 #define ISON_SIGNAL(x) (m23 & (byte)(0x10 << (x)))
 #define MAYBE_DRAW_SIGNAL(x,y,z) if (HAS_SIGNAL(x)) DrawSignalHelper(ti, ISON_SIGNAL(x), ((y-0x4FB) << 4)|(z))
 
-		if (!(m5 & TRACK_BIT_DIAG2)) {
-			if (!(m5 & TRACK_BIT_DIAG1)) {
+		if (!(m5 & TRACK_BIT_Y)) {
+			if (!(m5 & TRACK_BIT_X)) {
 				if (m5 & TRACK_BIT_LEFT) {
 					MAYBE_DRAW_SIGNAL(2, 0x509, 0);
 					MAYBE_DRAW_SIGNAL(3, 0x507, 1);
@@ -1909,8 +1907,8 @@ static void TileLoop_Track(TileIndex tile)
 				PlayerID owner = GetTileOwner(tile);
 
 				if (rail == (TRACK_BIT_LOWER | TRACK_BIT_RIGHT) || (
-							!(rail & (TRACK_BIT_DIAG2 | TRACK_BIT_UPPER | TRACK_BIT_LEFT)) &&
-							(rail & TRACK_BIT_DIAG1)
+							!(rail & (TRACK_BIT_Y | TRACK_BIT_UPPER | TRACK_BIT_LEFT)) &&
+							(rail & TRACK_BIT_X)
 						)) {
 					TileIndex n = tile + TileDiffXY(0, -1);
 
@@ -1923,8 +1921,8 @@ static void TileLoop_Track(TileIndex tile)
 				}
 
 				if (rail == (TRACK_BIT_UPPER | TRACK_BIT_LEFT) || (
-							!(rail & (TRACK_BIT_DIAG2 | TRACK_BIT_LOWER | TRACK_BIT_RIGHT)) &&
-							(rail & TRACK_BIT_DIAG1)
+							!(rail & (TRACK_BIT_Y | TRACK_BIT_LOWER | TRACK_BIT_RIGHT)) &&
+							(rail & TRACK_BIT_X)
 						)) {
 					TileIndex n = tile + TileDiffXY(0, 1);
 
@@ -1938,8 +1936,8 @@ static void TileLoop_Track(TileIndex tile)
 				}
 
 				if (rail == (TRACK_BIT_LOWER | TRACK_BIT_LEFT) || (
-							!(rail & (TRACK_BIT_DIAG1 | TRACK_BIT_UPPER | TRACK_BIT_RIGHT)) &&
-							(rail & TRACK_BIT_DIAG2)
+							!(rail & (TRACK_BIT_X | TRACK_BIT_UPPER | TRACK_BIT_RIGHT)) &&
+							(rail & TRACK_BIT_Y)
 						)) {
 					TileIndex n = tile + TileDiffXY(-1, 0);
 
@@ -1952,8 +1950,8 @@ static void TileLoop_Track(TileIndex tile)
 				}
 
 				if (rail == (TRACK_BIT_UPPER | TRACK_BIT_RIGHT) || (
-							!(rail & (TRACK_BIT_DIAG1 | TRACK_BIT_LOWER | TRACK_BIT_LEFT)) &&
-							(rail & TRACK_BIT_DIAG2)
+							!(rail & (TRACK_BIT_X | TRACK_BIT_LOWER | TRACK_BIT_LEFT)) &&
+							(rail & TRACK_BIT_Y)
 						)) {
 					TileIndex n = tile + TileDiffXY(1, 0);
 
diff --git a/rail_map.h b/rail_map.h
index 35a0ddfd3..9affa2247 100644
--- a/rail_map.h
+++ b/rail_map.h
@@ -10,7 +10,7 @@
 
 static inline TrackBits GetRailWaypointBits(TileIndex t)
 {
-	return _m[t].m5 & RAIL_WAYPOINT_TRACK_MASK ? TRACK_BIT_DIAG2 : TRACK_BIT_DIAG1;
+	return _m[t].m5 & RAIL_WAYPOINT_TRACK_MASK ? TRACK_BIT_Y : TRACK_BIT_X;
 }
 
 
diff --git a/road_cmd.c b/road_cmd.c
index 3b2c8164e..152933390 100644
--- a/road_cmd.c
+++ b/road_cmd.c
@@ -239,10 +239,10 @@ int32 CmdRemoveRoad(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 
 					if (!(ti.map5 & 8)) {
 						if (pieces & ROAD_Y) goto return_error;
-						track = TRACK_BIT_DIAG2;
+						track = TRACK_BIT_Y;
 					} else {
 						if (pieces & ROAD_X) goto return_error;
-						track = TRACK_BIT_DIAG1;
+						track = TRACK_BIT_X;
 					}
 
 					cost = _price.remove_road * 2;
diff --git a/station_cmd.c b/station_cmd.c
index 98cdaf127..9ff2c3e7a 100644
--- a/station_cmd.c
+++ b/station_cmd.c
@@ -1033,7 +1033,7 @@ int32 CmdBuildRailroadStation(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 		st->build_date = _date;
 
 		tile_delta = direction ? TileDiffXY(0, 1) : TileDiffXY(1, 0);
-		track = direction ? TRACK_DIAG2 : TRACK_DIAG1;
+		track = direction ? TRACK_Y : TRACK_X;
 
 		statspec = (p2 & 0x10) != 0 ? GetCustomStation(STAT_CLASS_DFLT, p2 >> 8) : NULL;
 		layout_ptr = alloca(numtracks * plat_len);
@@ -1149,7 +1149,7 @@ int32 CmdRemoveFromRailroadStation(int x, int y, uint32 flags, uint32 p1, uint32
 
 	// if we reached here, it means we can actually delete it. do that.
 	if (flags & DC_EXEC) {
-		Track track = HASBIT(_m[tile].m5, 0) ? TRACK_DIAG2 : TRACK_DIAG1;
+		Track track = HASBIT(_m[tile].m5, 0) ? TRACK_Y : TRACK_X;
 		DoClearSquare(tile);
 		SetSignalsOnBothDir(tile, track);
 		// now we need to make the "spanned" area of the railway station smaller if we deleted something at the edges.
@@ -1228,7 +1228,7 @@ static int32 RemoveRailroadStation(Station *st, TileIndex tile, uint32 flags)
 				if (!EnsureNoVehicle(tile))
 					return CMD_ERROR;
 				if (flags & DC_EXEC) {
-					Track track = HASBIT(_m[tile].m5, 0) ? TRACK_DIAG2 : TRACK_DIAG1;
+					Track track = HASBIT(_m[tile].m5, 0) ? TRACK_Y : TRACK_X;
 					DoClearSquare(tile);
 					SetSignalsOnBothDir(tile, track);
 				}
diff --git a/waypoint.c b/waypoint.c
index dbe5728ea..a999ef2c3 100644
--- a/waypoint.c
+++ b/waypoint.c
@@ -183,8 +183,8 @@ int32 CmdBuildTrainWaypoint(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 	if (p1 >= GetNumCustomStations(STAT_CLASS_WAYP)) return CMD_ERROR;
 
 	if (!IsTileType(tile, MP_RAILWAY) || (
-				(axis = AXIS_X, _m[tile].m5 != TRACK_BIT_DIAG1) &&
-				(axis = AXIS_Y, _m[tile].m5 != TRACK_BIT_DIAG2)
+				(axis = AXIS_X, _m[tile].m5 != TRACK_BIT_X) &&
+				(axis = AXIS_Y, _m[tile].m5 != TRACK_BIT_Y)
 			)) {
 		return_cmd_error(STR_1005_NO_SUITABLE_RAILROAD_TRACK);
 	}