diff --git a/src/linkgraph/linkgraph_gui.cpp b/src/linkgraph/linkgraph_gui.cpp
index 21105981cb..8c9be0953a 100644
--- a/src/linkgraph/linkgraph_gui.cpp
+++ b/src/linkgraph/linkgraph_gui.cpp
@@ -17,6 +17,7 @@
 #include "../date_func.h"
 #include "../viewport_func.h"
 #include "../smallmap_gui.h"
+#include "../zoom_func.h"
 #include "../core/geometry_func.hpp"
 #include "../widgets/link_graph_legend_widget.h"
 
@@ -24,6 +25,8 @@
 
 #include "../3rdparty/cpp-btree/btree_map.h"
 
+#include <algorithm>
+
 #include "../safeguards.h"
 
 /**
@@ -40,25 +43,53 @@ const uint8 LinkGraphOverlay::LINK_COLOURS[] = {
  * Get a DPI for the widget we will be drawing to.
  * @param dpi DrawPixelInfo to fill with the desired dimensions.
  */
-void LinkGraphOverlay::GetWidgetDpi(DrawPixelInfo *dpi) const
+void LinkGraphOverlay::GetWidgetDpi(DrawPixelInfo *dpi, uint margin) const
 {
 	const NWidgetBase *wi = this->window->GetWidget<NWidgetBase>(this->widget_id);
-	dpi->left = dpi->top = 0;
-	dpi->width = wi->current_x;
-	dpi->height = wi->current_y;
+	dpi->left = dpi->top = -margin;
+	dpi->width = wi->current_x + 2 * margin;
+	dpi->height = wi->current_y + 2 * margin;
+}
+
+bool LinkGraphOverlay::CacheStillValid() const
+{
+	if (this->window->viewport) {
+		const ViewPort *vp = this->window->viewport;
+		Rect region { vp->virtual_left, vp->virtual_top,
+				vp->virtual_left + vp->virtual_width, vp->virtual_top + vp->virtual_height };
+		return (region.left >= this->cached_region.left &&
+				region.right <= this->cached_region.right &&
+				region.top >= this->cached_region.top &&
+				region.bottom <= this->cached_region.bottom);
+	} else {
+		return true;
+	}
 }
 
 /**
  * Rebuild the cache and recalculate which links and stations to be shown.
  */
-void LinkGraphOverlay::RebuildCache()
+void LinkGraphOverlay::RebuildCache(bool incremental)
 {
-	this->cached_links.clear();
-	this->cached_stations.clear();
+	if (!incremental) {
+		this->cached_links.clear();
+		this->cached_stations.clear();
+	}
 	if (this->company_mask == 0) return;
 
 	DrawPixelInfo dpi;
-	this->GetWidgetDpi(&dpi);
+	bool cache_all = false;
+	if (this->window->viewport) {
+		const ViewPort *vp = this->window->viewport;
+		const int pixel_margin = 256;
+		const int vp_margin = ScaleByZoom(pixel_margin, vp->zoom);
+		this->GetWidgetDpi(&dpi, pixel_margin);
+		this->cached_region = Rect({ vp->virtual_left - vp_margin, vp->virtual_top - vp_margin,
+				vp->virtual_left + vp->virtual_width + vp_margin, vp->virtual_top + vp->virtual_height + vp_margin });
+	} else {
+		this->GetWidgetDpi(&dpi);
+		cache_all = true;
+	}
 
 	struct LinkCacheItem {
 		Point from_pt;
@@ -66,8 +97,23 @@ void LinkGraphOverlay::RebuildCache()
 		LinkProperties prop;
 	};
 	btree::btree_map<std::pair<StationID, StationID>, LinkCacheItem> link_cache_map;
+	std::vector<StationID> incremental_station_exclude;
+	std::vector<std::pair<StationID, StationID>> incremental_link_exclude;
 
-	auto AddLinks = [&](const Station *from, const Station *to, Point from_pt, Point to_pt) {
+	if (incremental) {
+		incremental_station_exclude.reserve(this->cached_stations.size());
+		for (StationSupplyList::iterator i(this->cached_stations.begin()); i != this->cached_stations.end(); ++i) {
+			incremental_station_exclude.push_back(i->id);
+		}
+		std::sort(incremental_station_exclude.begin(), incremental_station_exclude.end());
+		incremental_link_exclude.reserve(this->cached_links.size());
+		for (LinkList::iterator i(this->cached_links.begin()); i != this->cached_links.end(); ++i) {
+			incremental_link_exclude.push_back(std::make_pair(i->from_id, i->to_id));
+		}
+		std::sort(incremental_link_exclude.begin(), incremental_link_exclude.end());
+	}
+
+	auto AddLinks = [&](const Station *from, const Station *to, Point from_pt, Point to_pt, btree::btree_map<std::pair<StationID, StationID>, LinkCacheItem>::iterator insert_iter) {
 		LinkCacheItem *item = nullptr;
 		CargoID c;
 		FOR_EACH_SET_CARGO_ID(c, this->cargo_mask) {
@@ -81,11 +127,10 @@ void LinkGraphOverlay::RebuildCache()
 			ConstEdge edge = lg[ge.node][to->goods[c].node];
 			if (edge.Capacity() > 0) {
 				if (!item) {
-					item = &link_cache_map[std::make_pair(from->index, to->index)];
-					if (item->prop.capacity == 0) {
-						item->from_pt = from_pt;
-						item->to_pt = to_pt;
-					}
+					auto iter = link_cache_map.insert(insert_iter, std::make_pair(std::make_pair(from->index, to->index), LinkCacheItem()));
+					item = &(iter->second);
+					item->from_pt = from_pt;
+					item->to_pt = to_pt;
 				}
 				this->AddStats(lg.Monthly(edge.Capacity()), lg.Monthly(edge.Usage()),
 						ge.flows.GetFlowVia(to->index), from->owner == OWNER_NONE || to->owner == OWNER_NONE,
@@ -98,6 +143,8 @@ void LinkGraphOverlay::RebuildCache()
 	FOR_ALL_STATIONS(sta) {
 		if (sta->rect.IsEmpty()) continue;
 
+		if (incremental && std::binary_search(incremental_station_exclude.begin(), incremental_station_exclude.end(), sta->index)) continue;
+
 		Point pta = this->GetStationMiddle(sta);
 
 		StationID from = sta->index;
@@ -114,9 +161,8 @@ void LinkGraphOverlay::RebuildCache()
 			for (ConstEdgeIterator i = from_node.Begin(); i != from_node.End(); ++i) {
 				StationID to = lg[i->first].Station();
 				assert(from != to);
-				if (!Station::IsValidID(to) || link_cache_map.count(std::make_pair(from, to))) {
-					continue;
-				}
+				if (!Station::IsValidID(to)) continue;
+
 				const Station *stb = Station::Get(to);
 				assert(sta != stb);
 
@@ -124,19 +170,28 @@ void LinkGraphOverlay::RebuildCache()
 				if (stb->owner != OWNER_NONE && sta->owner != OWNER_NONE && !HasBit(this->company_mask, stb->owner)) continue;
 				if (stb->rect.IsEmpty()) continue;
 
+				if (incremental && std::binary_search(incremental_station_exclude.begin(), incremental_station_exclude.end(), to)) continue;
+				if (incremental && std::binary_search(incremental_link_exclude.begin(), incremental_link_exclude.end(), std::make_pair(from, to))) continue;
+
+				auto key = std::make_pair(from, to);
+				auto iter = link_cache_map.lower_bound(key);
+				if (iter != link_cache_map.end() && !(link_cache_map.key_comp()(key, iter->first))) {
+					continue;
+				}
+
 				Point ptb = this->GetStationMiddle(stb);
 
-				if (!this->IsLinkVisible(pta, ptb, &dpi)) continue;
+				if (!cache_all && !this->IsLinkVisible(pta, ptb, &dpi)) continue;
 
-				AddLinks(sta, stb, pta, ptb);
+				AddLinks(sta, stb, pta, ptb, iter);
 			}
 		}
-		if (this->IsPointVisible(pta, &dpi)) {
+		if (cache_all || this->IsPointVisible(pta, &dpi)) {
 			this->cached_stations.push_back({ from, supply, pta });
 		}
 	}
 
-	this->cached_links.reserve(link_cache_map.size());
+	this->cached_links.reserve(this->cached_links.size() + link_cache_map.size());
 	for (auto &iter : link_cache_map) {
 		this->cached_links.push_back({ iter.first.first, iter.first.second, iter.second.from_pt, iter.second.to_pt, iter.second.prop });
 	}
diff --git a/src/linkgraph/linkgraph_gui.h b/src/linkgraph/linkgraph_gui.h
index a57e573989..bffcc1b913 100644
--- a/src/linkgraph/linkgraph_gui.h
+++ b/src/linkgraph/linkgraph_gui.h
@@ -68,7 +68,8 @@ public:
 			window(w), widget_id(wid), cargo_mask(cargo_mask), company_mask(company_mask), scale(scale)
 	{}
 
-	void RebuildCache();
+	void RebuildCache(bool incremental = false);
+	bool CacheStillValid() const;
 	void Draw(const DrawPixelInfo *dpi);
 	void SetCargoMask(CargoTypes cargo_mask);
 	void SetCompanyMask(uint32 company_mask);
@@ -86,6 +87,7 @@ protected:
 	uint32 company_mask;               ///< Bitmask of companies to be displayed.
 	LinkList cached_links;             ///< Cache for links to reduce recalculation.
 	StationSupplyList cached_stations; ///< Cache for stations to be drawn.
+	Rect cached_region;                ///< Region covered by cached_links and cached_stations.
 	uint scale;                        ///< Width of link lines.
 	uint64 last_update_number = 0;     ///< Last window update number
 
@@ -97,7 +99,7 @@ protected:
 	void DrawContent(Point pta, Point ptb, const LinkProperties &cargo) const;
 	bool IsLinkVisible(Point pta, Point ptb, const DrawPixelInfo *dpi, int padding = 0) const;
 	bool IsPointVisible(Point pt, const DrawPixelInfo *dpi, int padding = 0) const;
-	void GetWidgetDpi(DrawPixelInfo *dpi) const;
+	void GetWidgetDpi(DrawPixelInfo *dpi, uint margin = 0) const;
 
 	static void AddStats(uint new_cap, uint new_usg, uint new_flow, bool new_shared, LinkProperties &cargo);
 	static void DrawVertex(int x, int y, int size, int colour, int border_colour);
diff --git a/src/main_gui.cpp b/src/main_gui.cpp
index a36ac23789..d227ac208d 100644
--- a/src/main_gui.cpp
+++ b/src/main_gui.cpp
@@ -156,7 +156,7 @@ bool DoZoomInOutWindow(ZoomStateChange how, Window *w)
 	/* Update the windows that have zoom-buttons to perhaps disable their buttons */
 	w->InvalidateData();
 	if (how != ZOOM_NONE) {
-		RebuildViewportOverlay(w);
+		RebuildViewportOverlay(w, false);
 	}
 	return true;
 }
diff --git a/src/smallmap_gui.cpp b/src/smallmap_gui.cpp
index 2853bf25fc..283dd01baa 100644
--- a/src/smallmap_gui.cpp
+++ b/src/smallmap_gui.cpp
@@ -617,8 +617,6 @@ void SmallMapWindow::SetZoomLevel(ZoomLevelChange change, const Point *zoom_pt)
 			Point new_tile = this->PixelToTile(zoom_pt->x, zoom_pt->y, &sub);
 			this->SetNewScroll(this->scroll_x + (tile.x - new_tile.x) * TILE_SIZE,
 					this->scroll_y + (tile.y - new_tile.y) * TILE_SIZE, sub);
-		} else if (this->map_type == SMT_LINKSTATS) {
-			this->overlay->RebuildCache();
 		}
 		this->SetWidgetDisabledState(WID_SM_ZOOM_IN,  this->zoom == zoomlevels[MIN_ZOOM_INDEX]);
 		this->SetWidgetDisabledState(WID_SM_ZOOM_OUT, this->zoom == zoomlevels[MAX_ZOOM_INDEX]);
@@ -1538,7 +1536,6 @@ void SmallMapWindow::SetNewScroll(int sx, int sy, int sub)
 	this->scroll_x = sx;
 	this->scroll_y = sy;
 	this->subscroll = sub;
-	if (this->map_type == SMT_LINKSTATS) this->overlay->RebuildCache();
 }
 
 /* virtual */ void SmallMapWindow::OnScroll(Point delta)
diff --git a/src/smallmap_gui.h b/src/smallmap_gui.h
index 71e7b54522..ac2e7db41c 100644
--- a/src/smallmap_gui.h
+++ b/src/smallmap_gui.h
@@ -91,7 +91,7 @@ protected:
 
 	static const uint LEGEND_BLOB_WIDTH = 8;              ///< Width of the coloured blob in front of a line text in the #WID_SM_LEGEND widget.
 	static const uint INDUSTRY_MIN_NUMBER_OF_COLUMNS = 2; ///< Minimal number of columns in the #WID_SM_LEGEND widget for the #SMT_INDUSTRY legend.
-	static const uint FORCE_REFRESH_PERIOD = 0x1F; ///< map is redrawn after that many ticks
+	static const uint FORCE_REFRESH_PERIOD = 0x5F; ///< map is redrawn after that many ticks
 	static const uint BLINK_PERIOD         = 0x0F; ///< highlight blinking interval
 
 	uint min_number_of_columns;    ///< Minimal number of columns in legends.
diff --git a/src/viewport.cpp b/src/viewport.cpp
index 66477c223f..d49e6c94c0 100644
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -429,7 +429,7 @@ static void DoSetViewportPosition(const Window *w, int left, int top, int width,
 	}
 }
 
-static void SetViewportPosition(Window *w, int x, int y)
+static void SetViewportPosition(Window *w, int x, int y, bool force_update_overlay)
 {
 	ViewPort *vp = w->viewport;
 	int old_left = vp->virtual_left;
@@ -440,6 +440,8 @@ static void SetViewportPosition(Window *w, int x, int y)
 	vp->virtual_left = x;
 	vp->virtual_top = y;
 
+	if (force_update_overlay || IsViewportOverlayOutsideCachedRegion(w)) RebuildViewportOverlay(w, true);
+
 	/* Viewport is bound to its left top corner, so it must be rounded down (UnScaleByZoomLower)
 	 * else glitch described in FS#1412 will happen (offset by 1 pixel with zoom level > NORMAL)
 	 */
@@ -2823,7 +2825,7 @@ void UpdateViewportPosition(Window *w)
 
 		w->viewport->scrollpos_x = pt.x;
 		w->viewport->scrollpos_y = pt.y;
-		SetViewportPosition(w, pt.x, pt.y);
+		SetViewportPosition(w, pt.x, pt.y, false);
 	} else {
 		/* Ensure the destination location is within the map */
 		ClampViewportToMap(vp, w->viewport->dest_scrollpos_x, w->viewport->dest_scrollpos_y);
@@ -2850,8 +2852,7 @@ void UpdateViewportPosition(Window *w)
 
 		if (_scrolling_viewport == w) UpdateActiveScrollingViewport(w);
 
-		SetViewportPosition(w, w->viewport->scrollpos_x, w->viewport->scrollpos_y);
-		if (update_overlay) RebuildViewportOverlay(w);
+		SetViewportPosition(w, w->viewport->scrollpos_x, w->viewport->scrollpos_y, update_overlay);
 	}
 }
 
@@ -3438,13 +3439,24 @@ bool HandleViewportClicked(const ViewPort *vp, int x, int y, bool double_click)
 	return result;
 }
 
-void RebuildViewportOverlay(Window *w)
+void RebuildViewportOverlay(Window *w, bool incremental)
 {
 	if (w->viewport->overlay != NULL &&
 			w->viewport->overlay->GetCompanyMask() != 0 &&
 			w->viewport->overlay->GetCargoMask() != 0) {
-		w->viewport->overlay->RebuildCache();
-		w->SetDirty();
+		w->viewport->overlay->RebuildCache(incremental);
+		if (!incremental) w->SetDirty();
+	}
+}
+
+bool IsViewportOverlayOutsideCachedRegion(Window *w)
+{
+	if (w->viewport->overlay != NULL &&
+			w->viewport->overlay->GetCompanyMask() != 0 &&
+			w->viewport->overlay->GetCargoMask() != 0) {
+		return !w->viewport->overlay->CacheStillValid();
+	} else {
+		return false;
 	}
 }
 
@@ -3477,7 +3489,7 @@ bool ScrollWindowTo(int x, int y, int z, Window *w, bool instant)
 	if (instant) {
 		w->viewport->scrollpos_x = pt.x;
 		w->viewport->scrollpos_y = pt.y;
-		RebuildViewportOverlay(w);
+		RebuildViewportOverlay(w, true);
 	}
 
 	w->viewport->dest_scrollpos_x = pt.x;
diff --git a/src/viewport_func.h b/src/viewport_func.h
index d7d0159e3f..161aa9ebee 100644
--- a/src/viewport_func.h
+++ b/src/viewport_func.h
@@ -80,7 +80,8 @@ bool ScrollWindowTo(int x, int y, int z, Window *w, bool instant = false);
 
 void UpdateActiveScrollingViewport(Window *w);
 
-void RebuildViewportOverlay(Window *w);
+void RebuildViewportOverlay(Window *w, bool incremental);
+bool IsViewportOverlayOutsideCachedRegion(Window *w);
 
 bool ScrollMainWindowToTile(TileIndex tile, bool instant = false);
 bool ScrollMainWindowTo(int x, int y, int z = -1, bool instant = false);