diff --git a/src/ai/api/ai_rail.cpp b/src/ai/api/ai_rail.cpp
new file mode 100644
--- /dev/null
+++ b/src/ai/api/ai_rail.cpp
@@ -0,0 +1,442 @@
+/* $Id$ */
+
+/** @file ai_rail.cpp Implementation of AIRail. */
+
+#include "ai_rail.hpp"
+#include "ai_object.hpp"
+#include "ai_map.hpp"
+#include "../../openttd.h"
+#include "../../debug.h"
+#include "../../rail_map.h"
+#include "../../road_map.h"
+#include "../../command_type.h"
+#include "../../station_map.h"
+#include "../../company_func.h"
+#include "../../core/math_func.hpp"
+#include "../../waypoint.h"
+#include "../../newgrf.h"
+#include "../../newgrf_generic.h"
+#include "../../newgrf_station.h"
+#include "../../newgrf_callbacks.h"
+
+/* static */ bool AIRail::IsRailTile(TileIndex tile)
+{
+	if (!::IsValidTile(tile)) return false;
+
+	return (::IsTileType(tile, MP_RAILWAY) && !::IsRailDepot(tile)) ||
+			(::IsRailwayStationTile(tile) && !::IsStationTileBlocked(tile)) || ::IsLevelCrossingTile(tile);
+}
+
+/* static */ bool AIRail::IsLevelCrossingTile(TileIndex tile)
+{
+	if (!::IsValidTile(tile)) return false;
+
+	return ::IsLevelCrossingTile(tile);
+}
+
+/* static */ bool AIRail::IsRailDepotTile(TileIndex tile)
+{
+	if (!::IsValidTile(tile)) return false;
+
+	return ::IsRailDepotTile(tile);
+}
+
+/* static */ bool AIRail::IsRailStationTile(TileIndex tile)
+{
+	if (!::IsValidTile(tile)) return false;
+
+	return ::IsRailwayStationTile(tile);
+}
+
+/* static */ bool AIRail::IsRailWaypointTile(TileIndex tile)
+{
+	if (!::IsValidTile(tile)) return false;
+
+	return ::IsTileType(tile, MP_RAILWAY) && ::IsRailWaypointTile(tile);
+}
+
+/* static */ bool AIRail::IsRailTypeAvailable(RailType rail_type)
+{
+	if ((::RailType)rail_type < RAILTYPE_BEGIN || (::RailType)rail_type >= RAILTYPE_END) return false;
+
+	return ::HasRailtypeAvail(_current_company, (::RailType)rail_type);
+}
+
+/* static */ AIRail::RailType AIRail::GetCurrentRailType()
+{
+	return (RailType)AIObject::GetRailType();
+}
+
+/* static */ void AIRail::SetCurrentRailType(RailType rail_type)
+{
+	if (!IsRailTypeAvailable(rail_type)) return;
+
+	AIObject::SetRailType((::RailType)rail_type);
+}
+
+/* static */ bool AIRail::TrainCanRunOnRail(AIRail::RailType engine_rail_type, AIRail::RailType track_rail_type)
+{
+	if (!AIRail::IsRailTypeAvailable(engine_rail_type)) return false;
+	if (!AIRail::IsRailTypeAvailable(track_rail_type)) return false;
+
+	return ::IsCompatibleRail((::RailType)engine_rail_type, (::RailType)track_rail_type);
+}
+
+/* static */ bool AIRail::TrainHasPowerOnRail(AIRail::RailType engine_rail_type, AIRail::RailType track_rail_type)
+{\
+	if (!AIRail::IsRailTypeAvailable(engine_rail_type)) return false;
+	if (!AIRail::IsRailTypeAvailable(track_rail_type)) return false;
+
+	return ::HasPowerOnRail((::RailType)engine_rail_type, (::RailType)track_rail_type);
+}
+
+/* static */ AIRail::RailType AIRail::GetRailType(TileIndex tile)
+{
+	if (!AITile::HasTransportType(tile, AITile::TRANSPORT_RAIL)) return RAILTYPE_INVALID;
+
+	return (RailType)::GetRailType(tile);
+}
+
+/* static */ bool AIRail::ConvertRailType(TileIndex start_tile, TileIndex end_tile, AIRail::RailType convert_to)
+{
+	EnforcePrecondition(false, ::IsValidTile(start_tile));
+	EnforcePrecondition(false, ::IsValidTile(end_tile));
+	EnforcePrecondition(false, IsRailTypeAvailable(convert_to));
+
+	return AIObject::DoCommand(start_tile, end_tile, convert_to, CMD_CONVERT_RAIL);
+}
+
+/* static */ TileIndex AIRail::GetRailDepotFrontTile(TileIndex depot)
+{
+	if (!IsRailDepotTile(depot)) return INVALID_TILE;
+
+	return depot + ::TileOffsByDiagDir(::GetRailDepotDirection(depot));
+}
+
+/* static */ AIRail::RailTrack AIRail::GetRailStationDirection(TileIndex tile)
+{
+	if (!IsRailStationTile(tile)) return RAILTRACK_INVALID;
+
+	return (RailTrack)::GetRailStationTrack(tile);
+}
+
+/* static */ bool AIRail::BuildRailDepot(TileIndex tile, TileIndex front)
+{
+	EnforcePrecondition(false, tile != front);
+	EnforcePrecondition(false, ::IsValidTile(tile));
+	EnforcePrecondition(false, ::IsValidTile(front));
+	EnforcePrecondition(false, ::TileX(tile) == ::TileX(front) || ::TileY(tile) == ::TileY(front));
+	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));
+
+	uint entrance_dir = (::TileX(tile) == ::TileX(front)) ? (::TileY(tile) < ::TileY(front) ? 1 : 3) : (::TileX(tile) < ::TileX(front) ? 2 : 0);
+
+	return AIObject::DoCommand(tile, AIObject::GetRailType(), entrance_dir, CMD_BUILD_TRAIN_DEPOT);
+}
+
+/* static */ bool AIRail::BuildRailStation(TileIndex tile, RailTrack direction, uint num_platforms, uint platform_length, bool join_adjacent)
+{
+	EnforcePrecondition(false, ::IsValidTile(tile));
+	EnforcePrecondition(false, direction == RAILTRACK_NW_SE || direction == RAILTRACK_NE_SW);
+	EnforcePrecondition(false, num_platforms > 0 && num_platforms <= 0xFF);
+	EnforcePrecondition(false, platform_length > 0 && platform_length <= 0xFF);
+	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));
+
+	uint32 p1 = GetCurrentRailType() | (platform_length << 16) | (num_platforms << 8);
+	if (direction == RAILTRACK_NW_SE) p1 |= (1 << 4);
+	if (!join_adjacent) p1 |= (1 << 24);
+	return AIObject::DoCommand(tile, p1, INVALID_STATION << 16, CMD_BUILD_RAILROAD_STATION);
+}
+
+/* static */ bool AIRail::BuildNewGRFRailStation(TileIndex tile, RailTrack direction, uint num_platforms, uint platform_length, bool join_adjacent, CargoID cargo_id, IndustryType source_industry, IndustryType goal_industry, int distance, bool source_station)
+{
+	EnforcePrecondition(false, ::IsValidTile(tile));
+	EnforcePrecondition(false, direction == RAILTRACK_NW_SE || direction == RAILTRACK_NE_SW);
+	EnforcePrecondition(false, num_platforms > 0 && num_platforms <= 0xFF);
+	EnforcePrecondition(false, platform_length > 0 && platform_length <= 0xFF);
+	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));
+
+	uint32 p1 = GetCurrentRailType() | (platform_length << 16) | (num_platforms << 8);
+	if (direction == RAILTRACK_NW_SE) p1 |= 1 << 4;
+	if (!join_adjacent) p1 |= (1 << 24);
+
+	const GRFFile *file;
+	uint16 res = GetAiPurchaseCallbackResult(GSF_STATION, cargo_id, 0, source_industry, goal_industry, min(255, distance / 2), AICE_STATION_GET_STATION_ID, source_station ? 0 : 1, min(15, num_platforms) << 4 | min(15, platform_length), &file);
+	uint32 p2 = INVALID_STATION << 16;
+	if (res != CALLBACK_FAILED) {
+		extern StationClass _station_classes[STAT_CLASS_MAX];
+		const StationSpec *spec = GetCustomStationSpecByGrf(file->grfid, res);
+		int index = -1;
+		for (uint j = 0; j < _station_classes[spec->sclass].stations; j++) {
+			if (spec == _station_classes[spec->sclass].spec[j]) {
+				index = j;
+				break;
+			}
+		}
+		if (index == -1) {
+			DEBUG(grf, 1, "%s returned an invalid station ID for 'AI construction/purchase selection (18)' callback", file->filename);
+		} else {
+			p2 |= spec->sclass | index << 8;
+		}
+
+	}
+	return AIObject::DoCommand(tile, p1, p2, CMD_BUILD_RAILROAD_STATION);
+}
+
+/* static */ bool AIRail::RemoveRailStationTileRect(TileIndex tile, TileIndex tile2)
+{
+	EnforcePrecondition(false, ::IsValidTile(tile));
+	EnforcePrecondition(false, ::IsValidTile(tile2));
+
+	return AIObject::DoCommand(tile, tile2, 0, CMD_REMOVE_FROM_RAILROAD_STATION);
+}
+
+/* static */ uint AIRail::GetRailTracks(TileIndex tile)
+{
+	if (!IsRailTile(tile)) return RAILTRACK_INVALID;
+
+	if (IsRailWaypointTile(tile)) return ::GetRailWaypointBits(tile);
+	if (IsRailStationTile(tile)) return ::TrackToTrackBits(::GetRailStationTrack(tile));
+	if (IsLevelCrossingTile(tile)) return ::GetCrossingRailBits(tile);
+	return ::GetTrackBits(tile);
+}
+
+/* static */ bool AIRail::BuildRailTrack(TileIndex tile, RailTrack rail_track)
+{
+	EnforcePrecondition(false, ::IsValidTile(tile));
+	EnforcePrecondition(false, rail_track != 0);
+	EnforcePrecondition(false, (rail_track & ~::TRACK_BIT_ALL) == 0);
+	EnforcePrecondition(false, KillFirstBit((uint)rail_track) == 0);
+	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));
+
+	return AIObject::DoCommand(tile, tile, GetCurrentRailType() | (FindFirstTrack((::TrackBits)rail_track) << 4), CMD_BUILD_RAILROAD_TRACK);
+}
+
+/* static */ bool AIRail::RemoveRailTrack(TileIndex tile, RailTrack rail_track)
+{
+	EnforcePrecondition(false, ::IsValidTile(tile));
+	EnforcePrecondition(false, ::IsTileType(tile, MP_RAILWAY) && ::IsPlainRailTile(tile));
+	EnforcePrecondition(false, GetRailTracks(tile) & rail_track);
+	EnforcePrecondition(false, KillFirstBit((uint)rail_track) == 0);
+
+	return AIObject::DoCommand(tile, tile, GetCurrentRailType() | (FindFirstTrack((::TrackBits)rail_track) << 4), CMD_REMOVE_RAILROAD_TRACK);
+}
+
+/* static */ bool AIRail::AreTilesConnected(TileIndex from, TileIndex tile, TileIndex to)
+{
+	if (!IsRailTile(tile)) return false;
+	if (from == to || AIMap::DistanceManhattan(from, tile) != 1 || AIMap::DistanceManhattan(tile, to) != 1) return false;
+
+	if (to < from) ::Swap(from, to);
+
+	if (tile - from == 1) {
+		if (to - tile == 1) return (GetRailTracks(tile) & RAILTRACK_NE_SW) != 0;
+		if (to - tile == ::MapSizeX()) return (GetRailTracks(tile) & RAILTRACK_NE_SE) != 0;
+	} else if (tile - from == ::MapSizeX()) {
+		if (tile - to == 1) return (GetRailTracks(tile) & RAILTRACK_NW_NE) != 0;
+		if (to - tile == 1) return (GetRailTracks(tile) & RAILTRACK_NW_SW) != 0;
+		if (to - tile == ::MapSizeX()) return (GetRailTracks(tile) & RAILTRACK_NW_SE) != 0;
+	} else {
+		return (GetRailTracks(tile) & RAILTRACK_SW_SE) != 0;
+	}
+
+	NOT_REACHED();
+}
+
+/**
+ * Prepare the second parameter for CmdBuildRailroadTrack and CmdRemoveRailroadTrack. The direction
+ * depends on all three tiles. Sometimes the third tile needs to be adjusted.
+ */
+static uint32 SimulateDrag(TileIndex from, TileIndex tile, TileIndex *to)
+{
+	int diag_offset = abs(abs((int)::TileX(*to) - (int)::TileX(tile)) - abs((int)::TileY(*to) - (int)::TileY(tile)));
+	uint32 p2 = AIRail::GetCurrentRailType();
+	if (::TileY(from) == ::TileY(*to)) {
+		p2 |= (TRACK_X << 4);
+		*to -= Clamp((int)::TileX(*to) - (int)::TileX(tile), -1, 1);
+	} else if (::TileX(from) == ::TileX(*to)) {
+		p2 |= (TRACK_Y << 4);
+		*to -= ::MapSizeX() * Clamp((int)::TileY(*to) - (int)::TileY(tile), -1, 1);
+	} else if (::TileY(from) < ::TileY(tile)) {
+		if (::TileX(*to) < ::TileX(tile)) {
+			p2 |= (TRACK_UPPER << 4);
+		} else {
+			p2 |= (TRACK_LEFT << 4);
+		}
+		if (diag_offset) {
+			*to -= Clamp((int)::TileX(*to) - (int)::TileX(tile), -1, 1);
+		} else {
+			*to -= ::MapSizeX() * Clamp((int)::TileY(*to) - (int)::TileY(tile), -1, 1);
+		}
+	} else if (::TileY(from) > ::TileY(tile)) {
+		if (::TileX(*to) < ::TileX(tile)) {
+			p2 |= (TRACK_RIGHT << 4);
+		} else {
+			p2 |= (TRACK_LOWER << 4);
+		}
+		if (diag_offset) {
+			*to -= Clamp((int)::TileX(*to) - (int)::TileX(tile), -1, 1);
+		} else {
+			*to -= ::MapSizeX() * Clamp((int)::TileY(*to) - (int)::TileY(tile), -1, 1);
+		}
+	} else if (::TileX(from) < ::TileX(tile)) {
+		if (::TileY(*to) < ::TileY(tile)) {
+			p2 |= (TRACK_UPPER << 4);
+		} else {
+			p2 |= (TRACK_RIGHT << 4);
+		}
+		if (!diag_offset) {
+			*to -= Clamp((int)::TileX(*to) - (int)::TileX(tile), -1, 1);
+		} else {
+			*to -= ::MapSizeX() * Clamp((int)::TileY(*to) - (int)::TileY(tile), -1, 1);
+		}
+	} else if (::TileX(from) > ::TileX(tile)) {
+		if (::TileY(*to) < ::TileY(tile)) {
+			p2 |= (TRACK_LEFT << 4);
+		} else {
+			p2 |= (TRACK_LOWER << 4);
+		}
+		if (!diag_offset) {
+			*to -= Clamp((int)::TileX(*to) - (int)::TileX(tile), -1, 1);
+		} else {
+			*to -= ::MapSizeX() * Clamp((int)::TileY(*to) - (int)::TileY(tile), -1, 1);
+		}
+	}
+	return p2;
+}
+
+/* static */ bool AIRail::BuildRail(TileIndex from, TileIndex tile, TileIndex to)
+{
+	EnforcePrecondition(false, ::IsValidTile(from));
+	EnforcePrecondition(false, ::IsValidTile(tile));
+	EnforcePrecondition(false, ::IsValidTile(to));
+	EnforcePrecondition(false, ::DistanceManhattan(from, tile) == 1);
+	EnforcePrecondition(false, ::DistanceManhattan(tile,to) >= 1);
+	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));
+	int diag_offset = abs(abs((int)::TileX(to) - (int)::TileX(tile)) - abs((int)::TileY(to) - (int)::TileY(tile)));
+	EnforcePrecondition(false, diag_offset <= 1 ||
+			(::TileX(from) == ::TileX(tile) && ::TileX(tile) == ::TileX(to)) ||
+			(::TileY(from) == ::TileY(tile) && ::TileY(tile) == ::TileY(to)));
+
+	uint32 p2 = SimulateDrag(from, tile, &to);
+	return AIObject::DoCommand(tile, to, p2, CMD_BUILD_RAILROAD_TRACK);
+}
+
+/* static */ bool AIRail::RemoveRail(TileIndex from, TileIndex tile, TileIndex to)
+{
+	EnforcePrecondition(false, ::IsValidTile(from));
+	EnforcePrecondition(false, ::IsValidTile(tile));
+	EnforcePrecondition(false, ::IsValidTile(to));
+	EnforcePrecondition(false, ::DistanceManhattan(from, tile) == 1);
+	EnforcePrecondition(false, ::DistanceManhattan(tile,to) >= 1);
+	int diag_offset = abs(abs((int)::TileX(to) - (int)::TileX(tile)) - abs((int)::TileY(to) - (int)::TileY(tile)));
+	EnforcePrecondition(false, diag_offset <= 1 ||
+			(::TileX(from) == ::TileX(tile) && ::TileX(tile) == ::TileX(to)) ||
+			(::TileY(from) == ::TileY(tile) && ::TileY(tile) == ::TileY(to)));
+
+	if (!IsRailTypeAvailable(GetCurrentRailType())) SetCurrentRailType(GetRailType(tile));
+	uint32 p2 = SimulateDrag(from, tile, &to);
+	return AIObject::DoCommand(tile, to, p2, CMD_REMOVE_RAILROAD_TRACK);
+}
+
+/**
+ * Contains information about the trackdir that belongs to a track when entering
+ *   from a specific direction.
+ */
+struct AIRailSignalData {
+	Track track;        //!< The track that will be taken to travel.
+	Trackdir trackdir;  //!< The Trackdir belonging to that track.
+	uint signal_cycles; //!< How many times the signal should be cycled in order to build it in the correct direction.
+};
+
+static const int NUM_TRACK_DIRECTIONS = 3; //!< The number of directions you can go when entering a tile.
+
+/**
+ * List information about the trackdir and number of needed cycles for building signals when
+ *   entering a track from a specific direction. The first index is the difference between the
+ *   TileIndex of the previous and current tile, where (-)MapSizeX is replaced with -2 / 2 and
+ *   2 it added.
+ */
+static const AIRailSignalData _possible_trackdirs[5][NUM_TRACK_DIRECTIONS] = {
+	{{TRACK_UPPER,   TRACKDIR_UPPER_E, 0}, {TRACK_Y,       TRACKDIR_Y_SE,    0}, {TRACK_LEFT,    TRACKDIR_LEFT_S,  1}},
+	{{TRACK_RIGHT,   TRACKDIR_RIGHT_S, 1}, {TRACK_X,       TRACKDIR_X_SW,    1}, {TRACK_UPPER,   TRACKDIR_UPPER_W, 1}},
+	{{INVALID_TRACK, INVALID_TRACKDIR, 0}, {INVALID_TRACK, INVALID_TRACKDIR, 0}, {INVALID_TRACK, INVALID_TRACKDIR, 0}},
+	{{TRACK_LOWER,   TRACKDIR_LOWER_E, 0}, {TRACK_X,       TRACKDIR_X_NE,    0}, {TRACK_LEFT,    TRACKDIR_LEFT_N,  0}},
+	{{TRACK_RIGHT,   TRACKDIR_RIGHT_N, 0}, {TRACK_Y,       TRACKDIR_Y_NW,    1}, {TRACK_LOWER,   TRACKDIR_LOWER_W, 1}}
+};
+
+/* static */ AIRail::SignalType AIRail::GetSignalType(TileIndex tile, TileIndex front)
+{
+	if (AIMap::DistanceManhattan(tile, front) != 1) return SIGNALTYPE_NONE;
+	if (!::IsTileType(tile, MP_RAILWAY) || !::HasSignals(tile)) return SIGNALTYPE_NONE;
+
+	int data_index = 2 + (::TileX(front) - ::TileX(tile)) + 2 * (::TileY(front) - ::TileY(tile));
+
+	for (int i = 0; i < NUM_TRACK_DIRECTIONS; i++) {
+		const Track &track = _possible_trackdirs[data_index][i].track;
+		if (!(::TrackToTrackBits(track) & GetRailTracks(tile))) continue;
+		if (!HasSignalOnTrack(tile, track)) continue;
+		if (!HasSignalOnTrackdir(tile, _possible_trackdirs[data_index][i].trackdir)) continue;
+		SignalType st = (SignalType)::GetSignalType(tile, track);
+		if (HasSignalOnTrackdir(tile, ::ReverseTrackdir(_possible_trackdirs[data_index][i].trackdir))) st = (SignalType)(st | SIGNALTYPE_TWOWAY);
+		return st;
+	}
+
+	return SIGNALTYPE_NONE;
+}
+
+/**
+ * Check if signal_type is a valid SignalType.
+ */
+static bool IsValidSignalType(int signal_type)
+{
+	if (signal_type < AIRail::SIGNALTYPE_NORMAL || signal_type > AIRail::SIGNALTYPE_COMBO_TWOWAY) return false;
+	if (signal_type > AIRail::SIGNALTYPE_PBS_ONEWAY && signal_type < AIRail::SIGNALTYPE_NORMAL_TWOWAY) return false;
+	return true;
+}
+
+/* static */ bool AIRail::BuildSignal(TileIndex tile, TileIndex front, SignalType signal)
+{
+	EnforcePrecondition(false, AIMap::DistanceManhattan(tile, front) == 1)
+	EnforcePrecondition(false, ::IsTileType(tile, MP_RAILWAY) && ::IsPlainRailTile(tile));
+	EnforcePrecondition(false, ::IsValidSignalType(signal));
+
+	Track track = INVALID_TRACK;
+	uint signal_cycles;
+
+	int data_index = 2 + (::TileX(front) - ::TileX(tile)) + 2 * (::TileY(front) - ::TileY(tile));
+	for (int i = 0; i < NUM_TRACK_DIRECTIONS; i++) {
+		const Track &t = _possible_trackdirs[data_index][i].track;
+		if (!(::TrackToTrackBits(t) & GetRailTracks(tile))) continue;
+		track = t;
+		signal_cycles = _possible_trackdirs[data_index][i].signal_cycles;
+		break;
+	}
+	EnforcePrecondition(false, track != INVALID_TRACK);
+
+	uint p1 = track;
+	if (signal < SIGNALTYPE_TWOWAY) {
+		if (signal != SIGNALTYPE_PBS && signal != SIGNALTYPE_PBS_ONEWAY) signal_cycles++;
+		p1 |= (signal_cycles << 15);
+	}
+	p1 |= ((signal >= SIGNALTYPE_TWOWAY ? signal ^ SIGNALTYPE_TWOWAY : signal) << 5);
+
+	return AIObject::DoCommand(tile, p1, 0, CMD_BUILD_SIGNALS);
+}
+
+/* static */ bool AIRail::RemoveSignal(TileIndex tile, TileIndex front)
+{
+	EnforcePrecondition(false, AIMap::DistanceManhattan(tile, front) == 1)
+	EnforcePrecondition(false, GetSignalType(tile, front) != SIGNALTYPE_NONE);
+
+	Track track = INVALID_TRACK;
+	int data_index = 2 + (::TileX(front) - ::TileX(tile)) + 2 * (::TileY(front) - ::TileY(tile));
+	for (int i = 0; i < NUM_TRACK_DIRECTIONS; i++) {
+		const Track &t = _possible_trackdirs[data_index][i].track;
+		if (!(::TrackToTrackBits(t) & GetRailTracks(tile))) continue;
+		track = t;
+		break;
+	}
+	EnforcePrecondition(false, track != INVALID_TRACK);
+
+	return AIObject::DoCommand(tile, track, 0, CMD_REMOVE_SIGNALS);
+}