Five new payment kiosks for parking at the Sharon commuter rail station could be operating by the end of the week, Finance Director William Fowler said. The kiosks will accept debit, credit, and “smart” cards. The smart cards work like subway fare cards, but must be purchased from the town in advance. Riders can also pay by phone after boarding the train. Under the existing system, riders who do not have a quarterly pass have to stuff $4 in cash into a slot that corresponds to the parking spot. Fowler said the new system will eliminate the risks inherent in unloading dollar bills from the collection box in an unsecured parking lot, and will make fraud more difficult. Some riders wrap a dollar bill around something else — on several occasions, it was a Dora the Explorer game card — to make the slot appear full, he said.