1 files changed, 3 insertions, 0 deletions
diff --git a/ttd.h b/ttd.h
index d85bd9aae..4b6a0190a 100644
--- a/ttd.h
+++ b/ttd.h
@@ -42,6 +42,9 @@ typedef struct YearMonthDay {
 * * 1 day is thus about 2 seconds (74*27 = 1998) on a machine that can run OpenTTD normally
 */
 #define DAY_TICKS 74
+#define MAX_YEAR_BEGIN_REAL 1920
+#define MAX_YEAR_END_REAL 2090
+#define MAX_YEAR_END 170
 
 #include "macros.h"