What's the most depressing thing in America? Arriving in New York. Perhaps that answer requires some amplification. I've nothing against the city, one of the most thrilling destinations on earth. It's just the feeling you get on arriving by train from Washington DC, Boston or Philadelphia, only to be confronted by the unspeakably miserable ordeal of navigating Penn Station.
It wasn't always like that. The original 1910 station was a Beaux-Arts jewel, a monument of America's transient railway age. Its demolition exactly half a century ago might have been an act of unsurpassed architectural vandalism, but it was driven by dollars and cents. Rail traffic was declining, and there were far more lucrative uses for this supremely valuable chunk of real estate. So they flattened the old Penn Station and its soaring concourses, replacing it with a shabby, claustrophobic maze, and sticking the latest incarnation of the Madison Square Garden sports arena on top.
Alight at one of the ill-lit subterranean platforms where the trains now pull in, and the only thing missing is Charon, the ferryman of Hades, hand extended for the fare to cross the Styx. As the architectural historian Vincent Scully put it when mourning the first Penn's death, back then "you entered the city like a god. You scuttle in now like a rat."
Happily, though, change is on the horizon. The lease of Madison Square Garden – these days a tawdry also-ran alongside America's new generation of glitzy city-funded sports stadiums – is itself up for renewal, and is unlikely to be extended by the city authorities for more than 10 years.
Progress towards the most obvious solution, shifting the station to the grand United States Post Office building on the other side of Eighth Avenue, has bogged down. But just last week, four top design firms unveiled their visions of the future Penn Station. All of them were exhilarating, as different from the current one as day from night.
But happiest of all, there are still magnificent old stations dotted around the country, to remind you of the days when railways ruled. One of them, of course, is to be found in Manhattan, just a few blocks away. Grand Central Station had its own near-death experience, but escaped the wrecking ball in part because of the outcry generated by the destruction of the old Penn.
One of its champions was Jacqueline Kennedy. "If we don't care about our past, we can't have very much hope for our future," the former first lady declared at a press conference in the station's Oyster Bar in 1975, called to protest a plan to bury Grand Central under a skyscraper. The fight went all the way to the US Supreme Court. But this time, even as New York City faced bankruptcy, an irreplaceable monument was preserved.
In almost every great American city you will find a great station building. Here in Washington we have the best of both worlds, a bustling inter-city Union Station, that also happens to be a 1907 Beaux-Arts miracle, inspired by the Arch of Constantine and Baths of Caracalla of ancient Rome. The station is one of the top tourist attractions in a city brimming with them – even though the breathtaking central hall, of white granite and stucco embellished with gold leaf, is currently under partial wrap after the DC earthquake of August 2011. (Yes, it really was 5.8 on the Richter scale.)
Out in the real earthquake zone, Los Angeles has its own Union Station (so named when competing railroad companies joined forces to build a single station), replete with coloured marbles and Spanish colonial-style architecture. There's also a fine specimen in Denver – like LA a terminus for, among others, the Atchison, Topeka and Santa Fe. Did any railway on earth ever bear a finer name?
But the best of them, as you might suspect, are in the cities of the Midwest. It's the "rust belt" in today's throwaway parlance, but they were at their zenith in the early and mid 20th century, which happened also to be the zenith of the railway age. Measured by traffic, they are shadows of their former selves. Some have just a couple of trains a day; some are no longer stations at all, driven out of business by the car and the plane, stranded whales of transport history. But what buildings they are.
The working part of Pittsburgh's Union Station is now a sideshow. But the splendid rotunda that is its centrepiece remains a thing of wonder, with its marble floors and marvellous terracotta brickwork, illuminated by a colossal wrought-iron skylight.
Then there's the Union Station in St Louis, completed in 1894 and once the busiest in the entire US, but which last handled a serious train in 1978. The outside looks like a Romanesque fortress; the inside is a hotel and shopping complex, but the original Great Hall, a Moorish extravaganza, is still there, astounding visitors today no less than when St Louis hosted the World's Fair and Olympics in 1904.
My personal favourite, however, is Cincinnati, which I revisited earlier this month. The venerable Ohio river town hasn't had the best press over the years. "If the world comes to an end, I want to be in Cincinnati," Mark Twain wrote. "Everything comes there 10 years later." But its Union Station is something else, a perfectly preserved Art Deco masterpiece, its giant main hall surrounded by huge mosaic murals of the city's history. At its peak, 216 trains passed through daily. Today just a couple do, the merest afterthought for what is now Cincinnati's main museum complex.
And even in benighted Detroit, faint stirrings of railway station life can be detected. Of course, no train will ever again pass through Michigan Central, the once splendid, now derelict hulk whose abandonment and decay epitomise the city's dismal modern trajectory. Of late, though, a couple of long-broken windows have been replaced, and a few lights have appeared. The last glimmer of dusk – or herald of an improbable, still-distant rebirth for the rust belt's greatest casualty?