if (rvi->flags & RVI_WAGON) return CmdBuildRailWagon(p1, tile, flags);

	value = EstimateTrainCost(rvi);

	//make sure we only pay for half a dualheaded engine if we only requested half of it

	if (rvi->flags&RVI_MULTIHEAD && HASBIT(p2,0))

		value /= 2;

	if (!(flags & DC_QUERY_COST)) {

		v = AllocateVehicle();