A battle is brewing over the oft-plagued roll out of Presto in the Toronto subway system, one that serves as a reminder that local transit agencies aren't so harmoniously integrated.

According to a report from the Toronto Star, the TTC is seeking $4.2 million from Metrolinx for lost revenue to malfunctioning Presto readers technology. While the Commission has already billed the provincial transit agency for the losses, it has yet to pony up payment.

Despite an agreement that stipulates Metrolinx is on the hook for lost revenue related to faulty Presto technology, one reason it hasn't compensated the TTC just yet might be that it contends that its incurred extra costs related to updating technology on old streetcars.

Those Bombardier delays really do have a huge ripple effect.

Speaking to the Star, Metrolinx spokesperson Anne-Marie Atkins explains that "There is an ongoing negotiation regarding claims Metrolinx has against TTC and TTC has against Metrolinx... we are confident that working together we can resolve it."

Fingers crossed.