diff --git a/src/newgrf.cpp b/src/newgrf.cpp
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -314,7 +314,8 @@ public:
 
 typedef void (*SpecialSpriteHandler)(ByteReader *buf);
 
-static const uint NUM_STATIONS_PER_GRF = 255; ///< Number of StationSpecs per NewGRF; limited to 255 to allow extending Action3 with an extended byte later on.
+/** The maximum amount of stations a single GRF is allowed to add */
+static const uint NUM_STATIONS_PER_GRF = UINT16_MAX - 1;
 
 /** Temporary engine data used when loading only */
 struct GRFTempEngineData {
@@ -1988,7 +1989,7 @@ static ChangeInfoResult StationChangeInf
 			}
 
 			case 0x0A: { // Copy sprite layout
-				byte srcid = buf->ReadByte();
+				uint16_t srcid = buf->ReadExtendedByte();
 				const StationSpec *srcstatspec = srcid >= _cur.grffile->stations.size() ? nullptr : _cur.grffile->stations[srcid].get();
 
 				if (srcstatspec == nullptr) {
@@ -2042,7 +2043,7 @@ static ChangeInfoResult StationChangeInf
 				break;
 
 			case 0x0F: { // Copy custom layout
-				byte srcid = buf->ReadByte();
+				uint16_t srcid = buf->ReadExtendedByte();
 				const StationSpec *srcstatspec = srcid >= _cur.grffile->stations.size() ? nullptr : _cur.grffile->stations[srcid].get();
 
 				if (srcstatspec == nullptr) {
diff --git a/src/newgrf_roadstop.h b/src/newgrf_roadstop.h
--- a/src/newgrf_roadstop.h
+++ b/src/newgrf_roadstop.h
@@ -20,7 +20,7 @@
 #include "road.h"
 
 /** The maximum amount of roadstops a single GRF is allowed to add */
-static const int NUM_ROADSTOPS_PER_GRF = 255;
+static const int NUM_ROADSTOPS_PER_GRF = UINT16_MAX - 1;
 
 enum RoadStopClassID : byte {
 	ROADSTOP_CLASS_BEGIN = 0,    ///< The lowest valid value