diff --git a/src/autoreplace_cmd.cpp b/src/autoreplace_cmd.cpp
--- a/src/autoreplace_cmd.cpp
+++ b/src/autoreplace_cmd.cpp
@@ -412,7 +412,7 @@ static CommandCost ReplaceChain(Vehicle 
 
 	if (old_head->type == VEH_TRAIN) {
 		/* Store the length of the old vehicle chain, rounded up to whole tiles */
-		uint16 old_total_length = (Train::From(old_head)->tcache.cached_total_length + TILE_SIZE - 1) / TILE_SIZE * TILE_SIZE;
+		uint16 old_total_length = CeilDiv(Train::From(old_head)->tcache.cached_total_length, TILE_SIZE) * TILE_SIZE;
 
 		int num_units = 0; ///< Number of units in the chain
 		for (Train *w = Train::From(old_head); w != NULL; w = w->GetNextUnit()) num_units++;