X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Flibmarklin%2Ftrain.cpp;h=5bc50d85ff23ee5011535e34e5e6142f6b08fccc;hb=2029c5e4220e0809a39744a28ca9e2ff22e8ad28;hp=96566a63a5f48fe89049b5c1f7c3a2a601d46e66;hpb=848a39d9cf52c7158968ba3f9af4fd5d4e2b4391;p=r2c2.git

diff --git a/source/libmarklin/train.cpp b/source/libmarklin/train.cpp
index 96566a6..5bc50d8 100644
--- a/source/libmarklin/train.cpp
+++ b/source/libmarklin/train.cpp
@@ -24,6 +24,19 @@ Distributed under the GPL
 using namespace std;
 using namespace Msp;
 
+namespace {
+
+struct SetFlag
+{
+	bool &flag;
+
+	SetFlag(bool &f): flag(f) { flag = true; }
+	~SetFlag() { flag = false; }
+};
+
+}
+
+
 namespace Marklin {
 
 Train::Train(Layout &l, const VehicleType &t, unsigned a):
@@ -31,6 +44,7 @@ Train::Train(Layout &l, const VehicleType &t, unsigned a):
 	loco_type(t),
 	address(a),
 	priority(0),
+	yielding_to(0),
 	pending_block(0),
 	reserving(false),
 	advancing(false),
@@ -41,8 +55,6 @@ Train::Train(Layout &l, const VehicleType &t, unsigned a):
 	speed_changing(false),
 	reverse(false),
 	functions(0),
-	route(0),
-	next_route(0),
 	end_of_route(false),
 	status("Unplaced"),
 	travel_dist(0),
@@ -92,6 +104,11 @@ void Train::set_priority(int p)
 	priority = p;
 }
 
+void Train::yield_to(const Train &t)
+{
+	yielding_to = &t;
+}
+
 void Train::add_vehicle(const VehicleType &vt)
 {
 	Vehicle *veh = new Vehicle(layout, vt);
@@ -188,61 +205,179 @@ void Train::set_timetable(Timetable *tt)
 
 void Train::set_route(const Route *r)
 {
-	if(!rsv_blocks.empty())
-	{
-		for(list<BlockRef>::iterator i=rsv_blocks.begin(); i!=rsv_blocks.end(); ++i)
-			if(i->block->get_sensor_id())
-			{
-				release_blocks(rsv_blocks, ++i, rsv_blocks.end());
-				break;
-			}
-	}
+	free_noncritical_blocks();
 
-	route = r;
-	next_route = 0;
+	routes.clear();
+	if(r)
+		routes.push_back(r);
 	end_of_route = false;
 
-	if(route)
+	if(r && !cur_blocks.empty())
 	{
+		BlockRef &first = cur_blocks.front();
 		BlockRef &last = (rsv_blocks.empty() ? cur_blocks.back() : rsv_blocks.back());
 		BlockRef next = last.next();
-		const Block::Endpoint &ep = next.block->get_endpoints()[next.entry];
-		if(!route->get_tracks().count(ep.track))
+		const Block::Endpoint &first_ep = first.block->get_endpoints()[first.entry];
+		const Block::Endpoint &next_ep = next.block->get_endpoints()[next.entry];
+		if(!r->has_track(*next_ep.track))
 		{
-			next_route = route;
-			route = Route::find(*ep.track, ep.track_ep, *next_route);
+			Route *lead = Route::find(*next_ep.track, next_ep.track_ep, *r);
+			create_lead_route(lead, lead);
+			routes.push_front(lead);
 		}
+		else if(!r->has_track(*first_ep.track))
+			routes.push_front(create_lead_route(0, r));
 	}
 
 	reserve_more();
 
-	signal_route_changed.emit(route);
+	signal_route_changed.emit(get_route());
 }
 
-void Train::go_to(const Track &to)
+void Train::go_to(Track &to)
 {
 	for(list<BlockRef>::const_iterator i=cur_blocks.begin(); i!=cur_blocks.end(); ++i)
-		if(i->block->get_tracks().count(const_cast<Track *>(&to)))
+		if(i->block->has_track(to))
 		{
 			signal_arrived.emit();
 			set_route(0);
 			return;
 		}
 
-	BlockRef *last = 0;
-	if(rsv_blocks.empty())
-		last = &cur_blocks.back();
+	free_noncritical_blocks();
+
+	BlockRef &last = (rsv_blocks.empty() ? cur_blocks.back() : rsv_blocks.back());
+	BlockRef next = last.next();
+	const Block::Endpoint &ep = next.block->get_endpoints()[next.entry];
+
+	Route *route = Route::find(*ep.track, ep.track_ep, to);
+	create_lead_route(route, route);
+	set_route(route);
+}
+
+bool Train::divert(Track &from)
+{
+	if(!from.get_turnout_id())
+		throw InvalidParameterValue("Can't divert from a non-turnout");
+	if(routes.empty())
+		return false;
+
+	int path = -1;
+	unsigned from_ep = 0;
+	list<RouteRef>::iterator route = routes.begin();
+	Block *block = cur_blocks.back().block;
+	unsigned entry = cur_blocks.back().entry;
+	set<const Track *> visited;
+
+	// Follow our routes to find out where we're entering the turnout
+	while(1)
+	{
+		Block *link = block->get_link(block->traverse(entry, route->route));
+		entry = link->get_endpoint_by_link(*block);
+		block = link;
+
+		const Block::Endpoint &entry_ep = block->get_endpoints()[entry];
+
+		if(visited.count(entry_ep.track))
+			return false;
+		visited.insert(entry_ep.track);
+
+		if(!advance_route(route, *entry_ep.track))
+			return false;
+
+		if(entry_ep.track==&from)
+		{
+			if(block->get_train()==this && !free_block(*block))
+				return false;
+
+			from_ep = entry_ep.track_ep;
+			path = route->route->get_turnout(from.get_turnout_id());
+			break;
+		}
+	}
+
+	// Check that more than one path is available
+	unsigned ep_paths = from.get_type().get_endpoints()[from_ep].paths;
+	if(!(ep_paths&(ep_paths-1)))
+		return false;
+
+	// Choose some other path
+	for(int i=0; ep_paths>>i; ++i)
+		if((ep_paths&(1<<i)) && i!=path)
+		{
+			path = i;
+			break;
+		}
+
+	Track *track = from.get_link(from.traverse(from_ep, path));
+	if(!track)
+		return false;
+
+	unsigned ep = track->get_endpoint_by_link(from);
+
+	set<Track *> tracks;
+	for(list<RouteRef>::iterator i=routes.begin(); i!=routes.end(); ++i)
+		tracks.insert(i->route->get_tracks().begin(), i->route->get_tracks().end());
+	Route *diversion = 0;
+	try
+	{
+		diversion = Route::find(*track, ep, tracks);
+	}
+	catch(const Msp::Exception &)
+	{
+		return false;
+	}
+
+	diversion->set_name("Diversion");
+	diversion->add_track(from);
+	diversion->set_turnout(from.get_turnout_id(), path);
+
+	if(!is_valid_diversion(*diversion, from, from_ep))
+	{
+		delete diversion;
+		return false;
+	}
+
+	// Follow the diversion route until we get back to the original route
+	list<RouteRef>::iterator end = routes.end();
+	while(1)
+	{
+		path = 0;
+		if(track->get_turnout_id())
+			path = diversion->get_turnout(track->get_turnout_id());
+		Track *next = track->get_link(track->traverse(ep, path));
+
+		for(list<RouteRef>::iterator i=route; (end==routes.end() && i!=routes.end()); ++i)
+			if(i->route->has_track(*next))
+				end = i;
+
+		if(end!=routes.end())
+			break;
+		else if(!diversion->has_track(*next))
+			throw Exception("Pathfinder returned a bad route");
+
+		ep = next->get_endpoint_by_link(*track);
+		track = next;
+	}
+
+	if(route==end)
+		// We are rejoining the same route we diverted from, duplicate it
+		routes.insert(end, *route);
 	else
 	{
-		for(list<BlockRef>::iterator i=rsv_blocks.begin(); (i!=rsv_blocks.end() && !last); ++i)
-			if(i->block->get_sensor_id())
-				last = &*i;
+		++route;
+		routes.erase(route, end);
 	}
+	routes.insert(end, RouteRef(diversion, from.get_turnout_id()));
 
-	BlockRef next = last->next();
-	const Block::Endpoint &ep = next.block->get_endpoints()[next.entry];
+	return true;
+}
 
-	set_route(Route::find(*ep.track, ep.track_ep, to));
+const Route *Train::get_route() const
+{
+	if(routes.empty())
+		return 0;
+	return routes.front().route;
 }
 
 void Train::place(Block &block, unsigned entry)
@@ -269,17 +404,38 @@ void Train::place(Block &block, unsigned entry)
 		const Block::Endpoint &bep = block.get_endpoints()[exit];
 		Track *track = bep.track->get_link(bep.track_ep);
 		unsigned ep = track->get_endpoint_by_link(*bep.track);
-		vehicles.front()->place(track, ep, 0, Vehicle::FRONT_BUFFER);
+		vehicles.front()->place(*track, ep, 0, Vehicle::FRONT_BUFFER);
 	}
 	else
 	{
 		const Block::Endpoint &bep = block.get_endpoints()[entry];
-		vehicles.back()->place(bep.track, bep.track_ep, 0, Vehicle::BACK_BUFFER);
+		vehicles.back()->place(*bep.track, bep.track_ep, 0, Vehicle::BACK_BUFFER);
 	}
 }
 
+void Train::unplace()
+{
+	if(controller->get_speed())
+		throw InvalidState("Must be stopped before unplacing");
+
+	release_blocks(rsv_blocks);
+	release_blocks(cur_blocks);
+
+	set_active(false);
+	accurate_position = false;
+
+	for(vector<Vehicle *>::iterator i=vehicles.begin(); i!=vehicles.end(); ++i)
+		(*i)->unplace();
+
+	set_status("Unplaced");
+}
+
 bool Train::free_block(Block &block)
 {
+	float margin = 10*layout.get_catalogue().get_scale();
+	if(get_reserved_distance_until(&block, false)<controller->get_braking_distance()*1.3+margin)
+		return false;
+
 	unsigned nsens = 0;
 	for(list<BlockRef>::iterator i=rsv_blocks.begin(); i!=rsv_blocks.end(); ++i)
 	{
@@ -297,64 +453,91 @@ bool Train::free_block(Block &block)
 	return false;
 }
 
-int Train::get_entry_to_block(Block &block) const
+void Train::free_noncritical_blocks()
 {
-	for(list<BlockRef>::const_iterator i=cur_blocks.begin(); i!=cur_blocks.end(); ++i)
-		if(i->block==&block)
-			return i->entry;
-	for(list<BlockRef>::const_iterator i=rsv_blocks.begin(); i!=rsv_blocks.end(); ++i)
-		if(i->block==&block)
-			return i->entry;
-	return -1;
-}
+	if(cur_blocks.empty() || rsv_blocks.empty())
+		return;
+
+	if(controller->get_speed()==0)
+	{
+		release_blocks(rsv_blocks);
+		return;
+	}
+
+	float margin = 10*layout.get_catalogue().get_scale();
+	float min_dist = controller->get_braking_distance()*1.3+margin;
 
-float Train::get_reserved_distance() const
-{
 	Vehicle &veh = *(reverse ? vehicles.back() : vehicles.front());
-	const VehicleType &vtype = veh.get_type();
 
 	Track *track = veh.get_track();
-	if(!track)
-		return 0;
-	unsigned entry = veh.get_entry();
+	list<BlockRef>::iterator block = cur_blocks.begin();
+	bool in_rsv = false;
+	while(block!=rsv_blocks.end() && !block->block->has_track(*track))
+	{
+		++block;
+		if(block==cur_blocks.end())
+		{
+			block = rsv_blocks.begin();
+			in_rsv = true;
+		}
+	}
 
-	float result = -vtype.get_length()/2;
+	unsigned entry = veh.get_entry();
+	float dist = veh.get_offset();
 	if(reverse)
-	{
 		entry = track->traverse(entry);
-		result += veh.get_offset();
-	}
 	else
-		result -= veh.get_offset();
+		dist = track->get_type().get_path_length(track->get_active_path())-dist;
+	dist -= veh.get_type().get_length()/2;
 
-	bool first = true;
-	list<BlockRef>::const_iterator block = cur_blocks.begin();
+	bool nsens = 0;
 	while(1)
 	{
-		if(!first || !reverse)
-			result += track->get_type().get_path_length(track->get_active_path());
-		first = false;
-
-		if(track->get_type().get_endpoints().size()<2)
-			return result;
-
-		unsigned exit = track->traverse(entry);
-		Track *next = track->get_link(exit);
+		Track *next = track->get_link(track->traverse(entry));
+		entry = next->get_endpoint_by_link(*track);
+		track = next;
 
-		while(!block->block->get_tracks().count(next))
+		if(!block->block->has_track(*track))
 		{
 			++block;
 			if(block==cur_blocks.end())
+			{
 				block = rsv_blocks.begin();
+				in_rsv = true;
+			}
 			if(block==rsv_blocks.end())
-				return result;
+				return;
+
+			if(dist>min_dist && nsens>0)
+			{
+				release_blocks(rsv_blocks, block, rsv_blocks.end());
+				return;
+			}
+
+			if(in_rsv && block->block->get_sensor_id())
+				++nsens;
 		}
 
-		entry = next->get_endpoint_by_link(*track);
-		track = next;
+		dist += track->get_type().get_path_length(track->get_active_path());
 	}
 }
 
+int Train::get_entry_to_block(Block &block) const
+{
+	for(list<BlockRef>::const_iterator i=cur_blocks.begin(); i!=cur_blocks.end(); ++i)
+		if(i->block==&block)
+			return i->entry;
+	for(list<BlockRef>::const_iterator i=rsv_blocks.begin(); i!=rsv_blocks.end(); ++i)
+		if(i->block==&block)
+			return i->entry;
+	return -1;
+}
+
+float Train::get_reserved_distance() const
+{
+	return get_reserved_distance_until(0, false);
+}
+
 void Train::tick(const Time::TimeStamp &t, const Time::TimeDelta &dt)
 {
 	if(!active && stop_timeout && t>=stop_timeout)
@@ -405,14 +588,13 @@ void Train::tick(const Time::TimeStamp &t, const Time::TimeDelta &dt)
 
 		bool ok = false;
 		for(list<BlockRef>::const_iterator i=cur_blocks.begin(); (!ok && i!=cur_blocks.end()); ++i)
-			ok = i->block->get_tracks().count(track);
+			ok = i->block->has_track(*track);
 
 		float d = get_real_speed(current_speed)*(dt/Time::sec);
 		if(ok)
 		{
-			advancing = true;
+			SetFlag setf(advancing);
 			vehicle.advance(reverse ? -d : d);
-			advancing = false;
 		}
 		else if(accurate_position)
 		{
@@ -426,56 +608,19 @@ void Train::tick(const Time::TimeStamp &t, const Time::TimeDelta &dt)
 	}
 	else if(end_of_route && rsv_blocks.empty())
 	{
+		set_active(false);
 		signal_arrived.emit();
 		set_route(0);
 	}
 
 	if(!cur_blocks.empty() && !cur_blocks.front().block->get_sensor_id())
 	{
-		Vehicle &veh = *(reverse ? vehicles.front() : vehicles.back());
+		float dist = get_reserved_distance_until(cur_blocks.front().block, true);
 
-		list<BlockRef>::iterator i = cur_blocks.begin();
-		const Block::Endpoint &bep = i->block->get_endpoints()[i->entry];
-
-		Track *track = bep.track;
-		unsigned entry = bep.track_ep;
-
-		bool found = false;
-		float dist = veh.get_offset();
-		if(reverse)
-			dist = veh.get_track()->get_type().get_path_length(veh.get_track()->get_active_path())-dist;
-		dist -= veh.get_type().get_length()/2;
-		while(1)
-		{
-			if(track==veh.get_track())
-			{
-				found = true;
-				break;
-			}
-
-			if(i!=cur_blocks.begin())
-			{
-				float path_len = track->get_type().get_path_length(track->get_active_path());
-				dist += path_len;
-			}
-
-			unsigned exit = track->traverse(entry);
-			Track *next = track->get_link(exit);
-			entry = next->get_endpoint_by_link(*track);
-			track = next;
-
-			if(!i->block->get_tracks().count(track))
-			{
-				++i;
-				if(i==cur_blocks.end())
-					break;
-			}
-		}
-
-		if(found && i!=cur_blocks.begin() && dist>10*layout.get_catalogue().get_scale())
+		if(dist>10*layout.get_catalogue().get_scale())
 		{
 			cur_blocks.front().block->reserve(0);
-			cur_blocks.erase(cur_blocks.begin());
+			cur_blocks.pop_front();
 		}
 	}
 }
@@ -507,12 +652,12 @@ void Train::save(list<DataFile::Statement> &st) const
 			st.push_back((DataFile::Statement("block"), i->block->get_id()));
 	}
 
-	if(route)
+	if(!routes.empty())
 	{
-		if(!route->is_temporary())
-			st.push_back((DataFile::Statement("route"), route->get_name()));
-		else if(next_route && !next_route->is_temporary())
-			st.push_back((DataFile::Statement("route"), next_route->get_name()));
+		list<RouteRef>::const_iterator i = routes.begin();
+		for(; (i!=routes.end() && i->route->is_temporary()); ++i) ;
+		if(i!=routes.end())
+			st.push_back((DataFile::Statement("route"), i->route->get_name()));
 	}
 
 	if(timetable)
@@ -605,10 +750,10 @@ void Train::sensor_event(unsigned addr, bool state)
 					{
 						Track *track = bep.track->get_link(bep.track_ep);
 						unsigned ep = track->get_endpoint_by_link(*bep.track);
-						vehicles.back()->place(track, ep, 0, Vehicle::BACK_AXLE);
+						vehicles.back()->place(*track, ep, 0, Vehicle::BACK_AXLE);
 					}
 					else
-						vehicles.front()->place(bep.track, bep.track_ep, 0, Vehicle::FRONT_AXLE);
+						vehicles.front()->place(*bep.track, bep.track_ep, 0, Vehicle::FRONT_AXLE);
 				}
 			}
 			last_entry_time = Time::now();
@@ -617,16 +762,15 @@ void Train::sensor_event(unsigned addr, bool state)
 			overshoot_dist = 0;
 
 			// Check if we've reached the next route
-			if(next_route)
+			if(routes.size()>1)
 			{
-				const set<const Track *> &rtracks = next_route->get_tracks();
+				const set<Track *> &rtracks = (++routes.begin())->route->get_tracks();
 				for(list<BlockRef>::iterator j=rsv_blocks.begin(); j!=i; ++j)
 					if(rtracks.count(j->block->get_endpoints()[j->entry].track))
 					{
-						route = next_route;
-						next_route = 0;
+						routes.pop_front();
 						// XXX Exceptions?
-						signal_route_changed.emit(route);
+						signal_route_changed.emit(routes.front().route);
 						break;
 					}
 			}
@@ -643,9 +787,14 @@ void Train::sensor_event(unsigned addr, bool state)
 	}
 	else
 	{
+		const Vehicle &veh = *(reverse ? vehicles.front() : vehicles.back());
+
 		// Find the first sensor in our current blocks that's still active
 		list<BlockRef>::iterator end = cur_blocks.begin();
 		for(list<BlockRef>::iterator i=cur_blocks.begin(); i!=cur_blocks.end(); ++i)
+		{
+			if(i->block->has_track(*veh.get_track()))
+				break;
 			if(i->block->get_sensor_id())
 			{
 				if(layout.get_driver().get_sensor(i->block->get_sensor_id()))
@@ -656,8 +805,9 @@ void Train::sensor_event(unsigned addr, bool state)
 					++end;
 				}
 			}
+		}
 		
-		if(end!=cur_blocks.begin())
+		if(end!=cur_blocks.begin() && end!=cur_blocks.end())
 			// Free blocks up to the last inactive sensor
 			release_blocks(cur_blocks, cur_blocks.begin(), end);
 	}
@@ -665,7 +815,7 @@ void Train::sensor_event(unsigned addr, bool state)
 
 void Train::turnout_event(unsigned addr, bool)
 {
-	if(pending_block)
+	if(pending_block && (!pending_block->get_train() || pending_block->get_train()==this))
 	{
 		unsigned pending_addr = pending_block->get_turnout_id();
 		bool double_addr = (*pending_block->get_tracks().begin())->get_type().is_double_address();
@@ -687,7 +837,7 @@ void Train::halt_event(bool h)
 
 void Train::block_reserved(const Block &block, const Train *train)
 {
-	if(&block==pending_block && !train)
+	if(&block==pending_block && !train && !reserving)
 		reserve_more();
 }
 
@@ -696,48 +846,61 @@ unsigned Train::reserve_more()
 	if(!active)
 		return 0;
 
-	BlockRef *last = 0;
+	BlockRef *start = 0;
 	if(!rsv_blocks.empty())
-		last = &rsv_blocks.back();
+		start = &rsv_blocks.back();
 	else if(!cur_blocks.empty())
-		last = &cur_blocks.back();
-	if(!last)
+		start = &cur_blocks.back();
+	if(!start)
 		return 0;
 
 	pending_block = 0;
 
-	// See how many sensor blocks we already have
+	// See how many sensor blocks and how much track we already have
 	unsigned nsens = 0;
+	float dist = 0;
 	for(list<BlockRef>::const_iterator i=rsv_blocks.begin(); i!=rsv_blocks.end(); ++i)
+	{
 		if(i->block->get_sensor_id())
 			++nsens;
+		if(nsens>0)
+		{
+			float length = 0;
+			i->block->traverse(i->entry, &length);
+			dist += length;
+		}
+	}
 	
 	if(end_of_route)
 		return nsens;
 
-	const Route *cur_route = 0;
-	if(route)
-	{
-		const set<Track *> &tracks = last->block->get_tracks();
-		for(set<Track *>::const_iterator i=tracks.begin(); (cur_route!=route && i!=tracks.end()); ++i)
-		{
-			if(route->get_tracks().count(*i))
-				cur_route = route;
-			else if(next_route && next_route->get_tracks().count(*i))
-				cur_route = next_route;
-		}
-	}
+	list<RouteRef>::iterator cur_route = routes.begin();
+	advance_route(cur_route, *start->block->get_endpoints()[start->entry].track);
 
-	reserving = true;
+	float approach_margin = 50*layout.get_catalogue().get_scale();
+	float min_dist = controller->get_braking_distance()*1.3+approach_margin*2;
 
-	bool got_more = false;
-	BlockRef *good = last;
+	BlockRef *last = start;
+	BlockRef *good = start;
+	Track *divert_track = 0;
+	bool try_divert = false;
 	unsigned good_sens = nsens;
-	while(good_sens<3)
+	float good_dist = dist;
+	Train *blocking_train = 0;
+	std::list<BlockRef> contested_blocks;
+
+	SetFlag setf(reserving);
+
+	while(good_sens<3 || good_dist<min_dist || !contested_blocks.empty())
 	{
 		// Traverse to the next block
-		unsigned exit = last->block->traverse(last->entry);
-		Block *link = last->block->get_link(exit);
+		float length = 0;
+		Block *link = 0;
+		{
+			const Route *route = (cur_route!=routes.end() ? cur_route->route : 0);
+			unsigned exit = last->block->traverse(last->entry, route, &length);
+			link = last->block->get_link(exit);
+		}
 		if(!link)
 			break;
 
@@ -747,48 +910,114 @@ unsigned Train::reserve_more()
 
 		const Block::Endpoint &entry_ep = link->get_endpoints()[entry];
 
-		if(cur_route)
+		if(cur_route!=routes.end())
 		{
-			if(cur_route!=next_route && next_route && next_route->get_tracks().count(entry_ep.track))
-				cur_route = next_route;
-			else if(!cur_route->get_tracks().count(entry_ep.track))
+			if(!advance_route(cur_route, *entry_ep.track))
 			{
 				// Keep the blocks if we arrived at the end of the route
-				good = last;
-				good_sens = nsens;
-				end_of_route = true;
+				if(!blocking_train)
+				{
+					good = last;
+					good_sens = nsens;
+					good_dist = dist;
+					end_of_route = true;
+				}
 				break;
 			}
 		}
-		else if(route && route->get_tracks().count(entry_ep.track))
-			cur_route = route;
+		else if(!routes.empty() && routes.front().route->has_track(*entry_ep.track))
+			cur_route = routes.begin();
 
 		if(link->get_endpoints().size()<2)
 		{
-			good = last;
-			good_sens = nsens;
+			if(!blocking_train)
+			{
+				good = last;
+				good_sens = nsens;
+				good_dist = dist;
+			}
 			break;
 		}
 
+		if(blocking_train)
+		{
+			if(link->get_train()!=blocking_train)
+			{
+				if(blocking_train->free_block(*contested_blocks.back().block))
+				{
+					// Roll back and start actually reserving the blocks
+					last = &rsv_blocks.back();
+					cur_route = routes.begin();
+					advance_route(cur_route, *last->block->get_endpoints()[last->entry].track);
+					if(blocking_train->get_priority()==priority)
+						blocking_train->yield_to(*this);
+					blocking_train = 0;
+					continue;
+				}
+				else
+				{
+					yield_to(*blocking_train);
+					pending_block = contested_blocks.front().block;
+					try_divert = divert_track;
+					break;
+				}
+			}
+			else
+			{
+				contested_blocks.push_back(BlockRef(link, entry));
+				last = &contested_blocks.back();
+				continue;
+			}
+		}
+
 		bool reserved = link->reserve(this);
 		if(!reserved)
 		{
-			// Ask a lesser priority train to free the block for us
-			if(link->get_train()->get_priority()<priority)
-				if(link->get_train()->free_block(*link))
+			/* We've found another train.  If it wants to exit the block from the
+			same endpoint we're trying to enter from or the other way around,
+			treat it as coming towards us.  Otherwise treat it as going in the
+			same direction. */
+			Train *other_train = link->get_train();
+			int other_entry = other_train->get_entry_to_block(*link);
+			if(other_entry<0)
+				throw LogicError("Block reservation inconsistency");
+
+			bool entry_conflict = (static_cast<unsigned>(entry)==link->traverse(other_entry));
+			bool exit_conflict = (link->traverse(entry)==static_cast<unsigned>(other_entry));
+			if(!entry_conflict && !last->block->get_turnout_id())
+			{
+				/* The other train is not coming to the blocks we're holding, so we
+				can keep them. */
+				good = last;
+				good_sens = nsens;
+				good_dist = dist;
+			}
+
+			int other_prio = other_train->get_priority();
+
+			if(!entry_conflict && !exit_conflict && other_prio<priority)
+			{
+				/* Ask a lesser priority train going to the same direction to free
+				the block for us */
+				if(other_train->free_block(*link))
 					reserved = link->reserve(this);
+			}
+			else if(other_train!=yielding_to && (other_prio<priority || (other_prio==priority && entry_conflict)))
+			{
+				/* A lesser priority train is coming at us, we must ask it to free
+				enough blocks to get clear of it to avoid a potential deadlock */
+				blocking_train = other_train;
+				contested_blocks.clear();
+				contested_blocks.push_back(BlockRef(link, entry));
+				last = &contested_blocks.back();
+				continue;
+			}
+			else if(divert_track && (entry_conflict || exit_conflict))
+				// We are blocked, but there's a diversion possibility
+				try_divert = true;
 
 			if(!reserved)
 			{
-				// If we found another train and it's not headed straight for us, we can keep the blocks we got
-				int other_entry = link->get_train()->get_entry_to_block(*link);
-				if(other_entry<0)
-					throw LogicError("Block reservation inconsistency");
-				if(static_cast<unsigned>(entry)!=link->traverse(other_entry))
-				{
-					good = last;
-					good_sens = nsens;
-				}
 				pending_block = link;
 				break;
 			}
@@ -797,21 +1026,29 @@ unsigned Train::reserve_more()
 		if(link->get_turnout_id())
 		{
 			const Endpoint &track_ep = entry_ep.track->get_type().get_endpoints()[entry_ep.track_ep];
+			bool multiple_paths = (track_ep.paths&(track_ep.paths-1));
 
-			// Keep the blocks reserved so far, as either us or the other train can diverge
-			good = last;
-			good_sens = nsens;
+			if(multiple_paths || !last->block->get_turnout_id())
+			{
+				/* We can keep the blocks reserved so far if we are facing the
+				points or if there was no turnout immediately before this one.
+				With multiple successive turnouts (as is common in crossovers) it's
+				best to hold at one we can divert from. */
+				good = last;
+				good_sens = nsens;
+				good_dist = dist;
+			}
 
 			// Figure out what path we'd like to take on the turnout
 			int path = -1;
-			if(cur_route)
-				path = cur_route->get_turnout(link->get_turnout_id());
+			for(list<RouteRef>::iterator i=cur_route; (path<0 && i!=routes.end()); ++i)
+				path = i->route->get_turnout(link->get_turnout_id());
 			if(path<0)
 				path = entry_ep.track->get_active_path();
-			if(!((track_ep.paths>>path)&1))
+			if(!(track_ep.paths&(1<<path)))
 			{
 				for(unsigned i=0; track_ep.paths>>i; ++i)
-					if((track_ep.paths>>i)&1)
+					if(track_ep.paths&(1<<i))
 						path = i;
 			}
 
@@ -826,27 +1063,34 @@ unsigned Train::reserve_more()
 					break;
 				}
 			}
+
+			if(multiple_paths && cur_route!=routes.end() && cur_route->diversion!=link->get_turnout_id())
+				/* There's multiple paths to be taken and we are on a route - take
+				note of the diversion possibility */
+				divert_track = entry_ep.track;
 		}
 
+		if(!contested_blocks.empty() && contested_blocks.front().block==link)
+			contested_blocks.pop_front();
+
 		rsv_blocks.push_back(BlockRef(link, entry));
 		last = &rsv_blocks.back();
 		if(last->block->get_sensor_id())
-		{
 			++nsens;
-			got_more = true;
-		}
+		if(nsens>0)
+			dist += length;
 	}
 
 	// Unreserve blocks that were not good
-	while(!rsv_blocks.empty() && last!=good)
+	while(!rsv_blocks.empty() && &rsv_blocks.back()!=good)
 	{
-		last->block->reserve(0);
-		rsv_blocks.erase(--rsv_blocks.end());
-		if(!rsv_blocks.empty())
-			last = &rsv_blocks.back();
+		rsv_blocks.back().block->reserve(0);
+		rsv_blocks.pop_back();
 	}
 
-	reserving = false;
+	if(!rsv_blocks.empty() && &rsv_blocks.back()!=start)
+		// We got some new blocks, so no longer need to yield
+		yielding_to = 0;
 
 	// Make any sensorless blocks at the beginning immediately current
 	list<BlockRef>::iterator i;
@@ -854,9 +1098,84 @@ unsigned Train::reserve_more()
 	if(i!=rsv_blocks.begin())
 		cur_blocks.splice(cur_blocks.end(), rsv_blocks, rsv_blocks.begin(), i);
 
+	if(try_divert && divert(*divert_track))
+		return reserve_more();
+
 	return good_sens;
 }
 
+float Train::get_reserved_distance_until(const Block *until_block, bool back) const
+{
+	if(cur_blocks.empty())
+		return 0;
+
+	Vehicle &veh = *(reverse!=back ? vehicles.back() : vehicles.front());
+	const VehicleType &vtype = veh.get_type();
+
+	Track *track = veh.get_track();
+	if(!track)
+		return 0;
+
+	list<BlockRef>::const_iterator block = cur_blocks.begin();
+	while(block!=rsv_blocks.end() && !block->block->has_track(*track))
+	{
+		++block;
+		if(block==cur_blocks.end())
+		{
+			if(back)
+				return 0;
+			block = rsv_blocks.begin();
+		}
+	}
+	if(block==rsv_blocks.end() || block->block==until_block)
+		return 0;
+
+	unsigned entry = veh.get_entry();
+
+	float result = veh.get_offset();
+	if(reverse!=back)
+		entry = track->traverse(entry);
+	else
+		result = track->get_type().get_path_length(track->get_active_path())-result;
+	result -= vtype.get_length()/2;
+
+	while(1)
+	{
+		if(track->get_type().get_endpoints().size()<2)
+			break;
+
+		Track *next = track->get_link(track->traverse(entry));
+
+		if(!block->block->has_track(*next))
+		{
+			if(back)
+			{
+				if(block==cur_blocks.begin())
+					break;
+				--block;
+			}
+			else
+			{
+				++block;
+				if(block==cur_blocks.end())
+					block = rsv_blocks.begin();
+				if(block==rsv_blocks.end())
+					break;
+			}
+
+			if(block->block==until_block)
+				break;
+		}
+
+		entry = next->get_endpoint_by_link(*track);
+		track = next;
+
+		result += track->get_type().get_path_length(track->get_active_path());
+	}
+
+	return result;
+}
+
 float Train::get_real_speed(unsigned i) const
 {
 	if(real_speed[i].weight)
@@ -894,9 +1213,11 @@ unsigned Train::find_speed(float real) const
 
 	unsigned low = 0;
 	unsigned high = 0;
+	unsigned last = 0;
 	for(unsigned i=0; (!high && i<=14); ++i)
 		if(real_speed[i].weight)
 		{
+			last = i;
 			if(real_speed[i].speed<real)
 				low = i;
 			else
@@ -911,7 +1232,7 @@ unsigned Train::find_speed(float real) const
 			else
 				return 0;
 		}
-		return min(static_cast<unsigned>(low*real/real_speed[low].speed), 14U);
+		return min(min(static_cast<unsigned>(low*real/real_speed[low].speed), 14U), last+3);
 	}
 
 	float f = (real-real_speed[low].speed)/(real_speed[high].speed-real_speed[low].speed);
@@ -953,6 +1274,100 @@ void Train::reverse_blocks(list<BlockRef> &blocks) const
 		i->entry = i->block->traverse(i->entry);
 }
 
+bool Train::advance_route(list<RouteRef>::iterator &iter, Track &track)
+{
+	while(iter!=routes.end() && !iter->route->has_track(track))
+		++iter;
+	if(iter==routes.end())
+		return false;
+
+	list<RouteRef>::iterator next = iter;
+	++next;
+	if(next!=routes.end() && next->diversion && next->route->has_track(track))
+		iter = next;
+
+	return true;
+}
+
+Route *Train::create_lead_route(Route *lead, const Route *target)
+{
+	if(!lead)
+	{
+		lead = new Route(layout);
+		lead->set_name("Lead");
+		lead->set_temporary(true);
+	}
+
+	set<Track *> tracks;
+	for(list<BlockRef>::iterator i=cur_blocks.begin(); i!=rsv_blocks.end(); )
+	{
+		const set<Track *> &btracks = i->block->get_tracks();
+		for(set<Track *>::const_iterator j=btracks.begin(); j!=btracks.end(); ++j)
+			if(!target || !target->has_track(**j))
+				tracks.insert(*j);
+
+		if(++i==cur_blocks.end())
+			i = rsv_blocks.begin();
+	}
+
+	lead->add_tracks(tracks);
+
+	return lead;
+}
+
+bool Train::is_valid_diversion(const Route &diversion, Track &from, unsigned from_ep)
+{
+	float diversion_len = 0;
+	Track *track = &from;
+	unsigned ep = from_ep;
+	while(diversion.has_track(*track))
+	{
+		unsigned path = 0;
+		if(track->get_turnout_id())
+			path = diversion.get_turnout(track->get_turnout_id());
+		diversion_len += track->get_type().get_path_length(path);
+
+		Track *next = track->get_link(track->traverse(ep, path));
+		ep = next->get_endpoint_by_link(*track);
+		track = next;
+
+		if(track==&from)
+			return false;
+	}
+
+	list<RouteRef>::iterator route = routes.begin();
+	if(!advance_route(route, from))
+		return false;
+
+	set<Track *> visited;
+	float route_len = 0;
+	track = &from;
+	ep = from_ep;
+	while(1)
+	{
+		unsigned path = 0;
+		if(track->get_turnout_id())
+			path = route->route->get_turnout(track->get_turnout_id());
+		route_len += track->get_type().get_path_length(path);
+
+		if(track!=&from && diversion.has_track(*track))
+			break;
+
+		if(visited.count(track))
+			return false;
+		visited.insert(track);
+
+		Track *next = track->get_link(track->traverse(ep, path));
+		ep = next->get_endpoint_by_link(*track);
+		track = next;
+
+		if(!advance_route(route, *track))
+			return false;
+	}
+
+	return diversion_len<route_len*1.2;
+}
+
 
 Train::BlockRef::BlockRef(Block *b, unsigned e):
 	block(b),
@@ -973,6 +1388,12 @@ Train::BlockRef Train::BlockRef::next() const
 }
 
 
+Train::RouteRef::RouteRef(const Route *r, unsigned d):
+	route(r),
+	diversion(d)
+{ }
+
+
 Train::RealSpeed::RealSpeed():
 	speed(0),
 	weight(0)
@@ -1006,7 +1427,8 @@ void Train::Loader::finish()
 	{
 		const BlockRef &blkref = obj.cur_blocks.front();
 		const Block::Endpoint &bep = blkref.block->get_endpoints()[blkref.entry];
-		obj.vehicles.back()->place(bep.track, bep.track_ep, 0, Vehicle::BACK_BUFFER);
+		float offset = 2*obj.layout.get_catalogue().get_scale();
+		obj.vehicles.back()->place(*bep.track, bep.track_ep, offset, Vehicle::BACK_BUFFER);
 
 		obj.set_status("Stopped");
 	}