"We don't yet have comparable numbers for Ventra," Chase said.
Officials at Pace, which provides an average of 124,000 rides on its fixed routes on an average weekday, compared with 1.7 million daily rides on the CTA, said they have figured out the error rate to some degree.
In September, the suburban bus agency recorded 3,675 cases in which a rider was unable to pay because of malfunctioning equipment, versus 3,075 such instances in September 2012, Pace spokesman Patrick Wilmot said. That's a 19.5 percent increase this year since Ventra was offered to all Pace and CTA riders Sept. 9, after a phase-in period involving Ventra student passes in late August.
Ventra is being used on about 40 percent of CTA trips and 22 percent of Pace bus trips.
Although CTA and Pace don't yet have a lot of information to disclose, the transit agencies did hint at an answer regarding a question about uncollected Ventra fares that the Tribune has been asking for several weeks: Is Cubic being penalized for lost fare revenue caused by system malfunctions?
"We anticipate there will be penalties for Cubic for September," Chase said. "We're still going through the data and examining the many very technical performance standards that must be met."
Wilmot, the Pace spokesman, said the agency has a process to report lost revenue to Cubic.
"We don't believe this will be a significant amount of money relative to our overall revenue collection, but as a public agency we believe it's very important to have the ability to be reimbursed," Wilmot said.
The rough transition to the new system that CTA President Forrest Claypool and CTA board Chairman Terry Peterson promised would be simple and a joy to use continued last week for customers who said they waited on hold for more than 30 minutes when they called the toll-free Ventra customer service line for help.
Claypool said Oct. 9 that he ordered Cubic to beef up staffing at the service center, from 100 to 300 customer agents, a process that he said would take three weeks. This week marks three weeks.
Fang, the overcharged CTA rider, said Friday that he finally did receive a callback from Ventra about his complaint.
"The lady this time was very nice, and she refunded all the extra fares I got charged for," he said. "I asked her how to avoid this double-tapping/charge issue, and she just said if you find out you get double-charged, call us and we will refund the fare. Obviously there's no solution yet."
Meanwhile, the CTA will soon announce a mail-in program for customers to transfer balances to their Ventra cards from their old, soon-to-expire fare cards, Chase said.
Details are still being worked out, she said. But the mail-in program will be extended to regular-fare and reduced-fare customers, including senior citizens who have card balances they can't use up before Dec. 15, when the old fare cards will no longer be accepted on trains and buses.
The CTA value-transfer offer will be similar to a mail-in program that Pace announced last week for commuters who have unused and unexpired Pace 10-ride Plus tickets (both the regular and reduced-fare versions) and Commuter Club Cards. More information, including a balance-transfer form, is available at pacebus.com/ventra. The deadline for mailing the form is Dec. 31.
The CTA is also holding balance-transfer events. Fare cards eligible for balance transfers include CTA and Pace stored-value magnetic stripe full-fare and reduced-fare cards and Chicago Cards. Chicago Card Plus, period passes, reduced-fare passes, passes sold in bulk and expired fare cards cannot be transferred.
A calendar of the balance-transfer events is at bit.ly/1eUndN5.
More events are planned, Chase said. But turnout has been light — an average attendance of 45 people — at the 21 events held so far.
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