diff --git a/src/saveload/linkgraph_sl.cpp b/src/saveload/linkgraph_sl.cpp
--- a/src/saveload/linkgraph_sl.cpp
+++ b/src/saveload/linkgraph_sl.cpp
@@ -23,7 +23,7 @@ typedef LinkGraph::BaseEdge Edge;
 
 const SettingDesc *GetSettingDescription(uint index);
 
-static uint _num_nodes;
+static uint16 _num_nodes;
 
 /**
  * Get a SaveLoad array for a link graph.