Thieves are breaking into railroad containers and emptying goods onto the tracks.
Boxes upon boxes of merchandise litter the tracks.
RELATED: FedEx worker caught on surveillance camera stealing packages in SF
Once the goods have been tossed out of moving freight trains, others swoop in looking for the most valuable items.
One Amazon customer who returned an item had no idea her delivery had been interrupted.
CBS LA reporter Kristin Lazar: So there was something you sent back but you just had no idea it never made it to its intended destination?
Customer: Yeah, I don't even know what would be in that box. I buy so much from Amazon and send so much back, I wouldn't even know what it was.
Union Pacific says this stretch of track was cleaned up just 30 days ago.
RELATED: US postal inspector encourages public to stay aware of mail theft, robberies
Police say they have increased patrols along this stretch of track and are looking at other technology to stop these crimes from happening.