--- a/disaster_cmd.c	Fri Aug 11 03:07:46 2006 +0000
+++ b/disaster_cmd.c	Fri Aug 11 09:42:12 2006 +0000
@@ -116,7 +116,6 @@
 static void SetDisasterVehiclePos(Vehicle *v, int x, int y, byte z)
 {
 	Vehicle *u;
-	int yt;
 
 	BeginVehicleMove(v);
 	v->x_pos = x;
@@ -129,11 +128,14 @@
 	EndVehicleMove(v);
 
 	if ( (u=v->next) != NULL) {
+		int safe_x = clamp(x, 0, MapMaxX() * TILE_SIZE);
+		int safe_y = clamp(y - 1, 0, MapMaxY() * TILE_SIZE);
 		BeginVehicleMove(u);
 
 		u->x_pos = x;
-		u->y_pos = yt = y - 1 - (max(z - GetSlopeZ(x, y-1), 0) >> 3);
-		u->z_pos = GetSlopeZ(x,yt);
+		u->y_pos = y - 1 - (max(z - GetSlopeZ(safe_x, safe_y), 0) >> 3);
+		safe_y = clamp(u->y_pos, 0, MapMaxY() * TILE_SIZE);
+		u->z_pos = GetSlopeZ(safe_x, safe_y);
 		u->direction = v->direction;
 
 		DisasterVehicleUpdateImage(u);