CHICAGO (CBS) — Delayed several months by glitches with the new Ventra fare system, the CTA has begun phasing out its old fare cards, with an eye towards a full switchover to Ventra by July 1.

CTA officials said 86 percent of its fares are now paid with a Ventra card, and the agency is pushing the last of its riders to make the switch to Ventra. Pace riders have been slower to make the change, with about 60 percent of the suburban bus agency’s fares paid with Ventra cards.

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Starting Thursday, CTA and Pace riders can no longer purchase the old magnetic stripe fare cards, which are used by about 12 percent of CTA customers. The 2 percent of users who still rely on the Chicago Card and Chicago Card Plus will no longer be allowed to add value to their cards.

On June 1, anyone with a magnetic stripe card will no longer be able to add value to those cards, and the CTA will stop accepting fares from both types of Chicago Cards.

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By July 1, all CTA and Pace customers must pay their fares with a Ventra card, or cash.

The CTA began phasing out its old fare cards in October, but because of multiple glitches with the Ventra system, officials reversed course until the Ventra contractor, Cubic Transportation Systems, fixed the system.

When the CTA began rolling out Ventra in earnest in October, many customers had problems activating their new cards, and Ventra hotlines were overwhelmed by complaint calls. In addition, many Ventra card readers malfunctioned, leading to thousands of customers getting free rides because the machines would not read their cards. Other riders often had their cards charged multiple times for a single ride.

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However, the CTA said Cubic – the private contractor which was paid nearly half a billion dollars to manage the new fare system – has met most of the performance standards in its contract since January.