The top up of the transportation card is the transportation cost.
The transportation card is the card that you use to pay for public transportation, and what you charge into the card is, of course, the transportation fee. The transportation card is a contactless IC card that can be used for public transportation such as buses and rail transit, and is used to pay money. Just a swipe, you can pay the required money, if there is no balance, you can recharge at a nearby recharge point.