A couple weeks ago, I toured the Amazon fulfillment center in Tracy, CA. Some observations:

It was very impressive. Watching the yellow plastic tubs flying around on conveyor belts, being sorted into different tracks automatically. It reminded me of the scene in "Monsters, Inc." where are the bedroom doors are flying around on different tracks.

Work was divided into different stages:

1. Taking delivery from supply trucks, checking that contents were correct and in good shape. Contents placed into tubs that were conveyed to multiple different areas of the warehouse.

2. Storing items. Tubs of incoming items were delivered to a storage station. Robots brought storage pods (6-7 feet tall) with many cubbies up to the station. Different pods had different sized cubbies. A storage worker would scan each item from the tubs, and choose some cubby to put the item into. It looked like a camera watched which cubby they stored into to record it. cubbies could hold multiple different items. Apparently they are careful to never put two similar items in the same cubby, to make it easier for the next stage:

3. Picking items from storage. When an order needs to be fulfilled, the robots would bring a line of pods up to a person who would pick the needed item out of the correct cubby of each pod. All the items would go into a tub, to be conveyed to somewhere else for packing.

4. Packing the items for shipment. A person gets the items out of the tub, puts them in the correct sizes box, adds the air pockets for protection and seals up the box, which is then conveyed to another machine that weighs them and labels them for shipment.

5. Outgoing shipping distributed to different trucks based on geo location to ship to.

We walked around the warehouse with a few guides, and headphones to be able to listen to them. Our guide was excellent in being able to explain things and genuinely enthusiastic about the whole process. At the end they gave us branded water bottles too.

I asked our guide what he thought would happen as they began to automate more and more of the jobs. He said that they would shift people over to new roles and gave an example of a time in the past when they automated some job and instead split up roles to have a separate person do QA / checking of orders where before the same person had to fill an order and check it. He also spoke of another fulfillment center in Southern California where they automated a job, then later reversed course and went back to all manual because the people at that center decided that it was done better that way for them. I was surprised that decisions over automation were made locally at each center.

We hung around the building afterward, and bought lunch from a taco truck outside, and ate at some picnic tables where many employees also ate. I talked to some of them to try to get a less biased perspective from the employees. When I asked them how they liked working there, the most common answer I got was "It's a job." They said that expectations were high and they had to work hard. Some shifts were more desirable than others. One man said that it was tough, but he was very loyal because a year before Amazon had chosen to pay for his cancer treatment and he said they didn't have to. I left with a positive impression of the operation.

I'd recommend taking the tour if there's a fulfillment center nearby. You need to register in advance for a time, but it's all free.