A new but not yet activated SmarTrip vending machine is covered with a plastic sheet at Friendship Heights metro stop. (Astrid Riecken/FOR THE WASHINGTON POST)

As part of Metro’s campaign to push riders to ditch paper Farecards, every station in the system was supposed to have a SmarTrip card vending machine by now.

The plan was to have at least one machine in each station by Sept. 1, two months after a raft of fare changes went into effect, including a $1 surcharge on trips paid for with paper Farecards.

But in nearly half of the system’s 86 stations, Metro riders still don’t have a way to buy a SmarTrip card because Metro failed to ensure that the new vending machines, which cost $12,000 a piece, complied with the Americans With Disabilities Act.

And it’s going to be months before the new machines are ready to come out from under the plastic sheets covering them at Friendship Heights, Clarendon and other stations.

That hasn’t stopped the transit agency from collecting the surcharge, which still catches some riders by surprise, despite notices on the fare machines.

“As a consumer, I was never informed that I was paying more because I am using the paper card,” Mauro Moran, a government contractor, said in a recent interview after entering the Twinbrook station using a paper card.

Moran said he had noticed that he was using up his fare value faster than usual but thought the reason was the fare increase that went into effect in July.

“Now I feel I have to switch to plastic,” he said.

Metro spokesman Dan Stessel said the agency took responsibility for the delay. “We erred in the rollout of these machines, and we apologize for any inconvenience,” he said.

The first shipment of the new machines did not have the audio and Braille features required under the Americans with Disabilities Act. But Metro thought it could roll out the machines and add the audio and Braille a couple of months later. When disability advocates raised concerns, Metro realized that going forward would violate the ADA, and the transit agency halted the rollout.

So nearly three weeks after every station was to have its own SmarTrip card dispenser, riders at nearly half of the stations in the Metrorail system are out of luck if they need to buy a card. And in the stations where they can buy cards, riders have to use older, less-reliable machines that are in line to be replaced.

The problems have marred what Metro considers an important — and so far still successful — effort to move riders away from paper Farecards.

The $1 surcharge that began in July was the first part of the push. Then came a $3 rebate for buying and registering $5 SmarTrip cards, although that did not kick off until this month, when a cheaper chip reduced the price of the cards.

And then there were the new SmarTrip card vending machines destined for stations that did not already have one of the older machines and eventually for all of the stations.

But a subcommittee meeting of Metro’s Accessibility Advisory Committee and a report last month in The Washington Post spurred questions from advocates of people with disabilities.

While the older machines have only Braille, which was sufficient when they were purchased in 2004, the new dispensers must have an audio function and Braille before they can be put into use, Stessel said.

Despite the delay, Metro’s SmarTrip push appears to be on its way to accomplishing its goal of saving money spent on printing paper cards and maintaining fare machines.

Metro sold 111,200 SmarTrip cards in August, an increase of 36 percent over the 81,563 sold during the same month last year. More than 15.2 million rides were taken with a SmarTrip in August, up from 14.2 million the year before, while paper card use was down to 2.8 million, from 3.7 million.

Samantha Barton, 29, bought her SmarTrip card the first time she saw a machine selling them at the Greenbelt station.

“I was like: ‘Finally! They’re selling these cards in the station,’ ” Barton said.

SmarTrip cards are available online and at Metro sales offices, commuter stores and multiple retail outlets. “Anyone who wants a SmarTrip has many, many options for getting one,” Stessel said.

But for a busy commuter, making a trip to a Giant or CVS solely to buy the card becomes another errand on a long to-do list.

“I’m just always in a rush,” said Malingo Namata, who still uses a paper card. “I have to get to work, or pick up my daughter. It does add up, though. I’m hoping to get a SmarTrip card some time in the near future.”

At least one rider is sticking with the paper cards by choice. Suzanne Henry of Austin still uses them because she can submit them as expenses when she’s in Washington for a conference.

“The train here is still so much cheaper” than a cab, she said in an interview at the Greenbelt station. “When I turn it in to expense it, they’re appreciative that I took the train at all. If I got a more permanent Metro pass, they wouldn’t know how to expense it anyway.”

Luz Lazo and Ted Trautman contributed to this report.