I think that is because of the vent grates on the street that have to deal more rain on the street surface because of climate change. This heat that is melting this sealant is from the train and air conditioning. But still a cool article, thanks for sending.

I'm sure you're right about storm sewers not keeping up with rain when it comes to the waterfalls coming down the entry stairways. I'm a bit skeptical about the torrents coming straight out of the ceilings. But I'm just guessing. Thanks for the exchange.