Image: the CSX viaduct in Baltimore/David Wilson
Freight rail transport on the United States' densely packed East Coast is anchored by a single rail line belonging to the CSX corporation. There are other rail lines in the East, of course, but this one, hugging Interstate 95 from Florida to New Jersey while connecting ocean ports, population centers, and the rest of the country's goods transportation network, is truly special. When the line reaches Maryland, just a little ways south of Baltimore, it's occupying the same route that once supported America's very first (real) railway, the Baltimore and Ohio. This is about where things go to shit.
Railways are big fans of things that work, less so of things that work more safety or even things that work more efficiently. Just after crossing onto the old B&O line, CSX trains cross the Thomas Viaduct, a nearly 200 year old stone bridge that looks like a piece of ancient Rome, and not long after that they'll find themselves in the Howard Street Tunnel. The tunnel, a relic of the late 1800s, caught fire in 2001 when a train carrying loads of bad-news chemicals jumped the tracks, spilling a full tanker of triproylene and 2,554 gallons of hydrochloric acid into a poorly ventilated, difficult-to-access hole underneath the downtown hub of a major US city.
The tunnel burned for almost a full week, with wood and paper goods going up along with the chemicals, effectively shutting down the entire central Baltimore core. It was an incident waiting to happen. An article from the Baltimore Sun quotes (as cited in the linked 2001 study on the fire) an unnamed federal transportation official as saying, "... the problem would be getting in there to fight the fire... If you had an explosion, fire would shoot out of both ends like a bazooka." Nothing much has changed since the accident.
A mile or so after the tunnel comes the next artifact, a viaduct carved through a quiet residential district called Charles Village, where trains pass below street level, like a tunnel without a roof. The passage is lined on either side by stone walls about a single story tall, themselves topped with wrought iron fencing. Like the tunnel, the viaduct dates back to the late 1800s; even the fencing is a century old. Finally, after days of epic rain, a wall of the viaduct collapsed (above), taking half a city street with it. Thankfully no one was hurt. Some residents are blaming the railroad, citing an extensive history of complaints pertaining to the long-sagging wall, while the city claims it performed structural tests on the viaduct only a year before, finding it safe.
The railway was reopened in less than a day, which shouldn't actually be a surprise. There's no way around for CSX trains and the line is the backbone of freight rail on the East Coast. Who knows how long it will take to get the street fixed, and I wouldn't count on the railway doing any major upgrades on the viaduct, at least without a court order and even then. So, I'm just presenting it as an example without much comment, of when infrastructure actually fails and what that looks like. Consider it a postcard from the future.