Record-high volume for holiday package deliveries wasn’t enough for the U.S. Postal Service to overcome its financial troubles last quarter, as the agency more than doubled its net loss from the same period in 2014.

Overall, the agency lost $754 million, despite a 4.3 percent increase in operating revenue compared with the first quarter of last year, according to the latest USPS financial statement.

The disappointing loss overshadowed several areas of growth for the Postal Service. Package volume jumped 12.8 percent and standard mail volume increased 3.5 percent, helping the agency improve its operating revenue by nearly $800 million.

(AP/Elaine Thompson)

USPS also increased its holiday-season package deliveries by 18 percent compared with the same time in 2013, dropping off more than 524 million parcels in December.

Megan Brennan, who became postmaster general and USPS chief executive this month, touted the gains as evidence that the agency is making progress. “In broad terms, we had a tremendous amount of momentum throughout the organization,” she said during a conference call with reporters on Friday.

But several factors kept the Postal Service from earning an overall profit, including a 1.1 percent decline in first-class mail volume, which is the agency’s biggest moneymaker.

Other drags included a congressionally mandated prepayment of retiree health benefits that cost the agency $1.4 billion and an $800 million increase in workers’ compensation expenses.

USPS Chief Financial Officer Joseph Corbett said legislative action will be needed to bring the Postal Service out of the red after eight consecutive years of losses.

Postal officials and unions have called on Congress to end or restructure the prefunding requirement for retiree health benefits, which has proven to be a massive drag on the agency’s finances since the mandate took effect in 2006. USPS has defaulted on the payment for the past four years.

An agreement on comprehensive postal legislation has eluded Congress for several years, with lawmakers from both parties opposing bipartisan plans that would involve service cuts such as an end to Saturday mail delivery.

Last month, USPS scaled back its mail-delivery standards, slowing first-class mail from one-day delivery to two days. The cuts are expected to increase the average delivery time from 1.8 days to 2.1 days, according to postal officials.

The agency has also begun closing dozens of mail-processing centers nationwide as part of a plan to save an estimated $750 million annually. The move is expected to increase delivery times for first-class mail from 2.14 days to 2.25 days, according to a USPS fact sheet.

Postal unions on Friday called for an end to the service cuts.

“This is a time to strengthen – not degrade – the now-profitable networks,” said NALC president Fredric Rolando. “We hope to work with lawmakers on both sides of the aisle, with the administration and with the new postmaster general to build on the progress achieved in the last Congress, within the mailing industry and among major stakeholders on consensus postal reform that promotes a strong and vibrant Postal Service.”