Like many postal workers, a mail carrier in northern Minnesota makes his way through his route in a small truck with balding tires.

It’s almost three decades old and was designed to carry letters and magazines along with some parcels. But the capacity is nothing on the scale of today’s mounds of packages from Amazon, Target and other retailers.

This mail carrier offered MPR News a look into his job provided his name won’t be made public.

“There is retribution out there,” he said, expressing fear management would make his job even more difficult if they knew he was speaking out.

He’s been a letter carrier for several years. Like others who have gone to lawmakers, the media or post office brass to raise concerns about delivery volume and working conditions, he’s fed up with the U.S. Postal Service for letting things get to this point.

“Most of my concerns are just prioritization of parcels over mail. The mail is second rate,” said the letter carrier, who maintains management has taken on too many package deliveries at the expense of conventional mail.

It’s a characterization the U.S. Postal Service disputes, but also one that has caught the attention of federal lawmakers from both parties, who are pressing for more answers.The postal worker said his job — especially this time of the year — is all-consuming. He often works more than 14 hours a day.

“My wife has woken me up countless times — I’m still in my uniform — laying on the couch to tell me I need to change and come to bed,” said the mail carrier.

The carrier said supervisors coerce him and his coworkers into working on days they are supposed to be off.

“Your manager comes up to you and says that ‘Oh hey, I know you’re hitting 88 hours this week, but I heard you volunteered to come in tomorrow,’” he said, using the term he and his colleagues have attached to the requests: “voluntold.”

“If you don’t comply, you hear about it,” he said. “You get definitely intimidated the following day. You get teased. You get taunted.”

Amazon told MPR News that it does not have an agreement with the postal service to prioritize its package deliveries. Amazon, which has had a business relationship with the postal service for years, said it works to balance its needs with postal service capacity.

The Postal Service declined an MPR News interview request to talk about mail carrier allegations. Instead, it provided a written statement saying it is “strongly positioned” to handle the onslaught of holiday package and mail deliveries.

Minnesota’s U.S. senators do not buy that line.

“I’ve heard about this from all over the state,” Democratic Sen. Tina Smith said. “But most recently from the Bemidji area where we have folks on rural routes that are waiting a long time to get their mail, their mail is very inconsistent.”

The postal service wrote to Smith earlier this month saying it was trying to hire more carriers for a peak season but hasn’t yet hit its goal. That is for 112 more employees in the Minnesota-North Dakota District; 24 were hired as of early December with more in the pipeline.

“In Minnesota, permanent hiring has also been an ongoing priority and ‘hiring hubs’ in the Twin Cities have allowed the district to hire dozens of new employees since August, with dozens more in process,” wrote Michael Gordon, who is part of the U.S.P.S. government relations team. “These hiring hubs have been so successful that we are looking to replicate them in other Minnesota cities.”

Smith said national postal leaders are dismissing legitimate concerns.

“What’s really distressing is when I reach out to the Postmaster General and his team here in Washington they say, ‘Don’t worry, everything is fine,’” Smith said. “So, they clearly do not have a bead on what’s happening with service or the terrible working conditions for their employees.”

Smith and fellow DFL Sen. Amy Klobuchar are pushing legislation that would require the postal service to keep better track of delivery problems and report them.

Another mail carrier, one who works in the Twin Cities area, also shared his on-the-job experience. He, too, asked that his name be withheld out of fear of retaliation from management.

Both mail carriers who participated in this story said they are considering quitting and they said many of their colleagues are also looking for options.

The Twin Cities carrier said his life is out of balance.

“I’ve had to give up pretty much every one of my hobbies,” he said. “It takes a toll on any relationships you have, any friendships. You don’t have a life outside of this job.”

Like his colleague in northern Minnesota, the Twin Cities postal worker said he and his colleagues struggle to keep up because they are delivering so many packages.

“The Amazon packages are the big thing that’s kind of killing us,” he said. “I’ve been working 60 to 80 hours a week.”