By John McDevitt

PHILADELPHIA (CBS) — Technical problems have cause SEPTA to suspend its “A” and “B” express trains on the Market-Frankford subway-elevated line during rush hour commutes this week.

The transit agency had to take train cars out of service to fix two problems, according to Ron Hopkins, assistant general manager of operations for SEPTA.

“One is our doors on the Market-Frankford line,” he told KYW Newsradio today, “and we are also having some propulsion faults.    Both are known problems we have been aggressively attacking with our engineering and our maintenance  departments.    We do have the solution.”

Riders may have noticed that it’s been standing room only on rush hour trains as all stops are made.

“The trains will tend to be more crowded, but we are trying to still get people to their destinations as we are trying to work out our problems,” Hopkins said.

SEPTA hopes normal express service will be restored by tomorrow morning.