Metro plans changes in its fare card dispensers. (Marlon Correa/The Washington Post)

The time is coming when you won’t choose paper or plastic, at least not to ride Metro.

The capital budget scheduled for approval by the Metro board on Thursday includes a plan to end the sale of paper fare cards and convert all riders to the plastic SmarTrip cards.

Most riders have made the switch already. About 93 percent of rail users are paying with SmarTrip, which saves them the $1 surcharge imposed on every ride taken with a paper card.

Under the program in the Fiscal Year 2015 capital budget, Metro would convert the newer fare-vending machines, the ones with the blue facing, so that they would dispense only the SmarTrip cards. About $8.7 million in a fund from the sale of Smartrip cards will cover the cost of retrofitting those machines. The equipment change-over would take about a year and a half, Metro spokesman Dan Stessel said. The older machines, the ones with a black facing, could be used to add value to an already purchased SmarTrip card.

Even after the conversion of the fare-vending machines, riders still would be able to use the paper cards they already had purchased. But Metro’s plan is to eventually eliminate the use of paper cards at the fare gates.

The paper cards can add to Metro’s maintenance problems by gumming up the fare gate machinery. Their use also just slows the process of getting riders through the fare gates, compared with the relatively quick tap on the top of the gate with a SmarTrip card.

A rider who wants to buy a SmarTrip card in a station today goes up to a blue machine that looks a little like R2D2, usually set off to the side of bigger fare-vending machines. Riders pay $10 at the dispenser, $2 of that is the cost of the card and the remaining $8 is fare value.