Across the five boroughs, a few remaining vintage diners still serve affordable, filling, no-frills comfort food in a city known for expensive gastronomic tastes.

At 9 am at the Cup & Saucer diner, located somewhat incongruously in the middle of New York City’s bustling Chinatown, business is brisk. High school students order breakfast sandwiches to go at the cash register, while regulars sit on stools at the white countertop, digging into plates loaded with pancakes, eggs cooked every way, sausage and hash browns. Coffee cups are filled and refilled as a chef shouts orders to the line cooks: “Silver dollars, go ahead! Eggs over easy, go ahead!”

The Cup & Saucer (89 Canal St; 212-925-3298) dates back to the 1940s, but like many vintage diners around the city that are threatened with increasing rents and an unstable economy, its future is uncertain. Last year, the building that houses the Cup & Saucer was sold, momentarily threatening the diner’s  ground floor location. “Looks like another five years at least,” said John Vasilopoulos hopefully, as he worked the register.

Staying true to the raison d’etre behind any iconic American diner – inexpensive, filling, no-frills comfort food, the Cup & Saucer serves breakfast specials from 6 am to 11 am daily for the unbeatably low price of $4.25. During lunch and dinner, customers peruse plastic-coated menus for classic greasy-spoon selections like hamburgers, French fries and club sandwiches stacked high with meat and iceberg lettuce.

The reality, however, is that in New York City, most diner food is not so cheap anymore. The term “diner” derives from the fact that these restaurants, popular not just in the Northeast but all across the United States, originally were built to resemble railroad dining cars. Though a few retain this style, such as the popular Carney’s in West Hollywood, California, nowadays diners tend to either be hole-in-the-wall luncheonettes or expansive, modern establishments with leather booths. Then there are the US’s faux “diner” chains like Denny’s and IHOP, which capture little of the spirit or flavour of the real thing.

According to the American Diner Museum in Lincoln, Rhode Island, the first diner was built in Providence, Rhode Island, in 1858, catering mostly to night workers. In that regard, things have not changed, as many diners are open 24 hours a day, seven days a week. You can often find as many customers eating tuna melts (hot grilled cheese and tuna sandwiches) at 3 am as there are eating Monte Cristos (fried ham and cheese sandwiches sprinkled with powdered sugar) at 3 pm. Diners also play an important role during every US election cycle. Candidates from both parties invariably make appearances at eateries in states like Iowa, Ohio, New Hampshire and Pennsylvania, trying to prove that they can relate to the common folk by eating a burger and slurping down a milkshake.

In New York City, across all five boroughs, one can still find many examples of classic, old school diners that, while not always dirt-cheap, provide a satisfying, comforting culinary experience that is still less expensive than many other restaurants in this venerable gastronomic city. These are, however, becoming increasingly imperilled, as property owners choose to raise rents instead of renewing vintage diners’ leases. For example, the Palace Diner, in Flushing, Queens, closed its doors last winter after nearly 40 years of service, and Manhattan’s iconic Empire Diner ceased operations in 2010 after being priced out of its location. Establishments like these might have survived by raising their prices, but that would have likely driven customers away.

Landmark Diner opened in Manhattan’s SoHo neighbourhood in 1962. It operates seven days a week, from 6 am until 6 pm. The narrow space between the grill counter and rickety tables is a bit dingy, but regulars flock here all day long for breakfast and lunch specials, coffee and burgers, served at a breakneck pace. Do not expect anything fancy; Landmark offers strictly down and dirty (metaphorically speaking) diner food, including a wide variety of omelettes, tuna salad sandwiches and grilled cheese with sliced tomatoes.

Neil’s Coffee Shop (961 Lexington Avenue; 212-628-7474) is another traditional establishment located on the Upper East Side of Manhattan, not far from museums like the Whitney and the Metropolitan Museum of Art. This diner exists in various shades of brown – tan booths, beige walls and light brown chairs. Headshots of celebrity patrons hang on a wall above the front dining room, including Liza Minnelli, George Stephanopoulos and Patrick Stewart. Neil’s opened in the 1950s, but Chris Kaloudis and his family have run the joint since 1980. “Have you looked at our prices?” he laughed when asked how business has fared as the US economy struggles. “The recession has definitely affected us,” he said. While a coffee and slice of cherry pie will set you back only $5, prices have risen over the past few years as tourism has declined and customers have been scarce. Still, Neil’s offers satisfying and sometimes greasy diner food that costs significantly less than many other Upper East Side restaurants.

In Brooklyn’s Prospect Heights neighbourhood, Tom’s Restaurant (782 Washington Avenue; 718-636-9738) has offered a quintessential diner experience since 1936. The egg creams (soda water mixed with chocolate or vanilla syrup and milk) and cherry-lime rickeys (lime juice and maraschino cherries mixed with lemon-lime soda) are not to be missed here. On weekend mornings, Tom’s is usually swarmed with customers hungry for brunch and there is often a wait, thanks to the enormous amount of breakfast dishes they have on the menu – more than 15 different types of pancakes (including sweet potato) and as many omelettes to match. In the mood for something savoury? Try the crab cakes or the excellent tuna melt, with fresh tomatoes and perfectly crisp fries – two dishes that go above and beyond the average diner fare. The interior design is a bit eccentric; Christmas lights cover the walls and a soundtrack of old-timey jazz plays as you eat.

There are, of course, classic diner experiences to be had in all corners of New York City. There’s another Tom’s Restaurant on the Upper West Side of Manhattan, which has been around since the 1940s, and was made famous by the Suzanne Vega song “Tom’s Diner” and as the exterior shots of Monk’s Diner on the TV show Seinfeld. Chelsea Square Restaurant (368 West 23rd Street; 212-691-5400) lies in the heart of Manhattan’s Chelsea neighbourhood and features many Greek dishes among the usual diner standbys.

Kellogg’s Diner (518 Metropolitan Avenue; 718-782-4502) in Brooklyn’s Williamsburg neighbourhood is another classic eatery, frequented by the young and fashionable residents who live in the area. A bit farther out, in Maspeth, Queens, the Clinton Diner and Bar (5626 Maspeth Avenue; 718-894-3475) has been around since 1935 and was prominently featured in the movie Goodfellas. A frequent stop for truck drivers, the Clinton Diner retains its retro 1950s look, with blue panelling along the outer wall and a jagged, blue structure jutting out from the rooftop.

In the Bronx, Castle Hill Diner (1506 Bronxdale Avenue; 718-828-3993) serves an eggs Benedict (poached eggs on an English muffin covered with Hollandaise sauce) that customers rave about in online reviews. Staten Island has its fair share of diners as well, including the Annadale Diner (813 Annadale Road; 718-984-3200), which features a full bar as well as dinner classics like roast chicken and broiled steaks.

It seems in every borough and neighbourhood of New York City, a grilled cheese, Western omelette, Greek salad and milkshake are just around the corner. Slide into a leather booth or sidle up to a lunch counter to enjoy an unpretentious meal while you can, because the classic diner may not be around for much longer.