diff --git a/src/linkgraph/linkgraph.cpp b/src/linkgraph/linkgraph.cpp
--- a/src/linkgraph/linkgraph.cpp
+++ b/src/linkgraph/linkgraph.cpp
@@ -65,7 +65,7 @@ void LinkGraph::ShiftDates(int interval)
 
 void LinkGraph::Compress()
 {
-	this->last_compression = (_date + this->last_compression) / 2;
+	this->last_compression = (TimerGameCalendar::date + this->last_compression) / 2;
 	for (NodeID node1 = 0; node1 < this->Size(); ++node1) {
 		this->nodes[node1].supply /= 2;
 		for (BaseEdge &edge : this->nodes[node1].edges) {
@@ -89,8 +89,8 @@ void LinkGraph::Compress()
  */
 void LinkGraph::Merge(LinkGraph *other)
 {
-	Date age = _date - this->last_compression + 1;
-	Date other_age = _date - other->last_compression + 1;
+	Date age = TimerGameCalendar::date - this->last_compression + 1;
+	Date other_age = TimerGameCalendar::date - other->last_compression + 1;
 	NodeID first = this->Size();
 	for (NodeID node1 = 0; node1 < other->Size(); ++node1) {
 		Station *st = Station::Get(other->nodes[node1].station);
@@ -172,8 +172,8 @@ void LinkGraph::BaseNode::AddEdge(NodeID
 	edge.capacity = capacity;
 	edge.usage = usage;
 	edge.travel_time_sum = static_cast<uint64>(travel_time) * capacity;
-	if (mode & EUM_UNRESTRICTED)  edge.last_unrestricted_update = _date;
-	if (mode & EUM_RESTRICTED) edge.last_restricted_update = _date;
+	if (mode & EUM_UNRESTRICTED)  edge.last_unrestricted_update = TimerGameCalendar::date;
+	if (mode & EUM_RESTRICTED) edge.last_restricted_update = TimerGameCalendar::date;
 }
 
 /**
@@ -239,8 +239,8 @@ void LinkGraph::BaseEdge::Update(uint ca
 		}
 		this->usage = std::max(this->usage, usage);
 	}
-	if (mode & EUM_UNRESTRICTED) this->last_unrestricted_update = _date;
-	if (mode & EUM_RESTRICTED) this->last_restricted_update = _date;
+	if (mode & EUM_UNRESTRICTED) this->last_unrestricted_update = TimerGameCalendar::date;
+	if (mode & EUM_RESTRICTED) this->last_restricted_update = TimerGameCalendar::date;
 }
 
 /**