Comment by _delirium | Hacker News Reader

Comment by _delirium | Hacker News Reader

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Using metal does seem to be the bulk of the strategy; the chassis and carriage will be aluminum.

I agree that the article isn't very clear on why existing cars aren't recyclable, and how this improves it. I could imagine that there are subway cars being produced in the past 10-20 years that are harder to recycle due to a bunch of plastic components, perhaps. Or, there might be issues in how the cars are constructed that make separating out the recyclable components unreasonably expensive?

It does seem to be the case that, whatever the reason, subway cars often aren't recycled. For example, New York repurposed a bunch of its old cars by sinking them to make artificial reefs: http://news.nationalgeographic.com/news/2006/08/060818-subwa.... Presumably they would've recycled them instead if the metal were easily reclaimable and had significant scrap value?

Aim of a transit authority isn't to get most of the metal back, but to dispose the vehicles as cheaply as possible. To conform with environmental regulations, labor safety, etc., is quite expensive. That's why you can find so many old German trams across the eastern Europe. German authorities eagerly "sold" their old trams for pretty much any cost (like 1 euro and pick-up), rather than scrap them, which would cost money and not bring that enough in scrap.

They probably didn't recycle those cars because they were full of asbestos. There was some controversy then about sinking them, though of course fish don't get mesothelioma. (I suppose toxins are the same reason electronic recycling is harder than it seems like it should be.)

Usually the hardest part with recycling is separating out the materials, especially once you start having components that are potentially toxic. For example, you could have an all metal subway car that has asbestos insulation... now your recycling cost is huge. Probably cheaper now to just bury the whole thing.

Recycling can raise or lower the cost of disposal, depending on construction and materials. Heavy use of adhesives pretty much makes recycling a nightmare, as well as complex mixes of plastics.

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