diff --git a/src/newgrf_gui.cpp b/src/newgrf_gui.cpp
index 1084e978dc..c9ac27f3cf 100644
--- a/src/newgrf_gui.cpp
+++ b/src/newgrf_gui.cpp
@@ -819,7 +819,7 @@ struct NewGRFWindow : public Window {
 				static char buff[512];
 				GRFBuildParamList(buff, this->sel, lastof(buff));
 				SetDParamStr(0, buff);
-				ShowQueryString(STR_JUST_RAW_STRING, STR_NEWGRF_SETTINGS_PARAMETER_QUERY, 63, 250, this, CS_ALPHANUMERAL, QSF_NONE);
+				ShowQueryString(STR_JUST_RAW_STRING, STR_NEWGRF_SETTINGS_PARAMETER_QUERY, 63, 250, this, CS_NUMERAL_SPACE, QSF_NONE);
 				break;
 			}
 
diff --git a/src/string.cpp b/src/string.cpp
index 6503f8fd12..d9e27857d3 100644
--- a/src/string.cpp
+++ b/src/string.cpp
@@ -194,9 +194,10 @@ void strtolower(char *str)
 bool IsValidChar(WChar key, CharSetFilter afilter)
 {
 	switch (afilter) {
-		case CS_ALPHANUMERAL: return IsPrintable(key);
-		case CS_NUMERAL:      return (key >= '0' && key <= '9');
-		case CS_ALPHA:        return IsPrintable(key) && !(key >= '0' && key <= '9');
+		case CS_ALPHANUMERAL:  return IsPrintable(key);
+		case CS_NUMERAL:       return (key >= '0' && key <= '9');
+		case CS_NUMERAL_SPACE: return (key >= '0' && key <= '9') || key == ' ';
+		case CS_ALPHA:         return IsPrintable(key) && !(key >= '0' && key <= '9');
 	}
 
 	return false;
diff --git a/src/string_type.h b/src/string_type.h
index 66b685ea39..40c1e2dc7e 100644
--- a/src/string_type.h
+++ b/src/string_type.h
@@ -18,6 +18,7 @@
 enum CharSetFilter {
 	CS_ALPHANUMERAL,      ///< Both numeric and alphabetic and spaces and stuff
 	CS_NUMERAL,           ///< Only numeric ones
+	CS_NUMERAL_SPACE,     ///< Only numbers and spaces
 	CS_ALPHA,             ///< Only alphabetic values
 };