diff --git a/src/newgrf.cpp b/src/newgrf.cpp
index 60ede9a40a..5b967d5ea4 100644
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -5919,6 +5919,18 @@ static bool ChangeGRFDescription(byte langid, const char *str)
 	return true;
 }
 
+/** Callback function for 'INFO'->'NPAR' to set the number of valid parameters. */
+static bool ChangeGRFNumUsedParams(size_t len, ByteReader *buf)
+{
+	if (len != 1) {
+		grfmsg(2, "StaticGRFInfo: expected only 1 byte for 'INFO'->'NPAR' but got " PRINTF_SIZE ", ignoring this field", len);
+		buf->Skip(len);
+	} else {
+		_cur_grfconfig->num_valid_params = min(buf->ReadByte(), lengthof(_cur_grfconfig->param));
+	}
+	return true;
+}
+
 typedef bool (*DataHandler)(size_t, ByteReader *);  ///< Type of callback function for binary nodes
 typedef bool (*TextHandler)(byte, const char *str); ///< Type of callback function for text nodes
 typedef bool (*BranchHandler)(ByteReader *);        ///< Type of callback function for branch nodes
@@ -6005,6 +6017,7 @@ struct AllowedSubtags {
 AllowedSubtags _tags_info[] = {
 	AllowedSubtags('NAME', ChangeGRFName),
 	AllowedSubtags('DESC', ChangeGRFDescription),
+	AllowedSubtags('NPAR', ChangeGRFNumUsedParams),
 	AllowedSubtags()
 };
 
diff --git a/src/newgrf_config.cpp b/src/newgrf_config.cpp
index 74c526b93f..d7769a394d 100644
--- a/src/newgrf_config.cpp
+++ b/src/newgrf_config.cpp
@@ -26,7 +26,8 @@
  * @param filename Set the filename of this GRFConfig to filename. The argument
  *   is copied so the original string isn't needed after the constructor.
  */
-GRFConfig::GRFConfig(const char *filename)
+GRFConfig::GRFConfig(const char *filename) :
+	num_valid_params(lengthof(param))
 {
 	if (filename != NULL) this->filename = strdup(filename);
 }
@@ -41,6 +42,7 @@ GRFConfig::GRFConfig(const GRFConfig &config) :
 	status(config.status),
 	grf_bugs(config.grf_bugs),
 	num_params(config.num_params),
+	num_valid_params(config.num_valid_params),
 	windows_paletted(config.windows_paletted)
 {
 	MemCpyT<uint8>(this->original_md5sum, config.original_md5sum, lengthof(this->original_md5sum));
diff --git a/src/newgrf_config.h b/src/newgrf_config.h
index 58e29afece..56131e766f 100644
--- a/src/newgrf_config.h
+++ b/src/newgrf_config.h
@@ -99,6 +99,7 @@ struct GRFConfig : ZeroedMemoryAllocator {
 	uint32 grf_bugs;    ///< NOSAVE: bugs in this GRF in this run, @see enum GRFBugs
 	uint32 param[0x80]; ///< GRF parameters
 	uint8 num_params;   ///< Number of used parameters
+	uint8 num_valid_params; ///< Number of valid parameters (action 0x14)
 	bool windows_paletted;  ///< Whether the NewGRF is Windows paletted or not
 
 	struct GRFConfig *next; ///< NOSAVE: Next item in the linked list