The Longest Conveyor Belt
One can easily detect it by the phosphate spillage south of it.As a teenager I worked at the end of a delivery conveyor belt for a supermarket. This was an unusual setup for a supermarket (but maybe for industrial or factory settings it's nothing special). The supermarket is located over a major highway. It's the Star Market over the Mass Pike/I90 outside of Boston (1). Customers had to take an escalator to the second floor, and after shopping and paying, 2-3 paper grocery bags were loaded into a small numbered cart. The customers were given plastic cards with the corresponding numbers.The carts were swung onto the top level of a double-decker conveyer belt. It went down to the first floor (street level) and into a long, basement like room with a conveyer belt and a road paralleling it. Customers would drive their cars into this long room, pop the trunk, and hand me their cards. I would match up the bags, and place them in the trunk. The empty carts were placed on the bottom level of the conveyer belt, to be brought back to the Muzak-filled main level of the supermarket.The room was filled with fumes and noise from the waiting cars and the interstate tunnel that was next to it. The incessant rattling and squeaking of thousands of metal rollers on the conveyer belts was irritating, although we got used to it (one thing I just realized -- upstairs where the customers were it was an actual belt, which was quiet, but down where we were it was those damn rollers, which were like 1950s-era metal roller skate wheels). We were paid $3.65/hour (minimum wage at the time). But the things that worried us from day to day was the cry of "mix" (human error, wrong bags placed in wrong car) or a spill.Here's what happened with the spills. As the carts came from the 2f to 1f, they went through a series of turns, including at least one 90 degree turn and a full 180 at the bottom of a decline. This spot was where most of the spills took place. It was apparently unavoidable, owing to the layout of the store, the location of the slopes on the belt, the road and loading area, and the needs of the customers to get their cars loaded quickly. The nature of groceries (heavy/light loads, multiple packaging sizes, etc.) and the technology used at the time made it hard to find an easy fix to the problem. Watermelons rolling around the bottom of the carts were the worst.I don't have any profound observations about this, other than spillage is a consideration for people who design and manage conveyer belts, and that the cost can be made manageable for both small and large systems. And these belts can be designed to last years or decades. The belt that we used in that market was in use for more than 20 years by the time I started working there in the 1980s, and it (or a similar system, using the same route) is still in use today, some 50 years after it was installed.1. https://www.google.com/maps/place/Shaw's+Supermarket/@42.350...