BAGHDAD — Saad al-Tammimi is in his fourth decade working for Iraq’s railroads, a career that has taken him all around his country, and around the Middle East. Nowadays, though, he can go only from Baghdad to Basra, across the relatively calm Shiite-dominated south of this war-torn country.

“If we have a problem and have to stop, it’s safe,” he said on a recent evening as he drove his regular route. “Even the Sunnis feel comfortable going to Basra.”

With so much violence, neglect and political dysfunction here, it has been years since passenger trains leaving Baghdad went anywhere other than Basra. In recent years, however, grand ambitions to link the country by railroad had begun taking shape. Freight trains shuttled goods around Iraq, and a few years ago there were test runs of a new train service between Mosul and Turkey. But as the militants of the Islamic State have advanced around the country, those efforts have halted.

At least Mr. Tammimi has a new train to drive, a sleek and shiny one built in China that glides out of the station at dusk and through the closed-in thicket of this city. It almost kisses the storefront awnings and low-slung homes that line the track as it moves past waving families, boys playing soccer and trash being burned, before reaching the rural south, past endless rows of date palms, on an overnight journey to Basra.

Inside are the luxuries of first-class rail travel, including flat-screen televisions and refrigerators in the sleeper cabins. Rowdy young army recruits, answering the call to arms from their Shiite religious leaders and on their way to basic training, crowd the brightly lit cafe car. The food is second-rate — cold fried chicken and soggy French fries — but there is a good falafel joint in Hilla, a town on the way; if you call in advance, sandwiches will be waiting at the station.

The new train is a small but noticeable sign of progress — of oil money spent in the interests of the public — in a country consumed by violence and corruption that is quickly coming apart in the face of an onslaught by the Sunni militants of the Islamic State, also called ISIS or ISIL.

It is also a reminder of what has been lost in Iraq and in the broader Middle East. Once, the region was connected by trains; building rail lines was central to the imperial ambitions of European powers — the Germans, the British and the French — to exert influence in the Middle East in the years before World War I, when the region was part of the Ottoman Empire. In more recent times, sectarian violence has torn apart diverse societies, especially in Iraq and Syria, that, for better or worse, were once held together by dictators. The areas reachable by trains have steadily shrunk, the diversity of the passengers who rode them a long-lost memory.

“Before was different,” said Ahmed Ali, who for 31 years has held various jobs for Iraqi Republic Railways, the state rail authority, and now works as a cashier in the cafe car. “I used to meet the educated people, the uneducated, the actors, the poets, the poor man. Many different groups.”

He adds, “Now, everything is gone.”

Mr. Ali recalled trips to Mosul, where on layovers he would visit the city’s famous tombs and shrines, and buy candy and pistachios and clothes to bring back to his family in Baghdad. For months now, Mosul, Iraq’s second-largest city, has been under control of the militants, and many of those historical sites have been destroyed.

On alternate evenings at dusk, the new train, which was introduced in recent months and would operate at high speed if it were not for the woeful condition of Iraq’s tracks, leaves for Basra. On the other nights, an older train, built by the French and in operation for almost three decades, makes the same 12-hour trip. That train may lack amenities, but it has an abundance of charm with its wood floors and paneling and green velvet seats in the cafe.

Riding the trains feels like an act of nostalgia — and, in some ways, an act of defiance, for the train represents connection in a place where people and communities are increasingly becoming detached from one another.

For those who have spent their lives working on Iraq’s railroads — jobs that have been passed down through generations, from father to son — each train journey is like a journey to the Iraq of their memories.

Ehab al-Shiekhly stood recently under a giant, twinkling chandelier in the grand, domed foyer of Baghdad Central Station, built by the British and opened in 1953. It is one of his favorite spots in the city.

“Sometimes I just sit here and take pictures of the dome,” said Mr. Shiekhly, 41, who has worked here for a quarter of a century, beginning as a teenager operating the telegraph machine. “It reminds me of the old days of Iraq, when it was safe.”

Standing under the chandelier, an old memory came to Mr. Shiekhly and he smiled, and pointed to a corner.

“Now you have to take tanks or jet fighters to get to these places,” said Ahmed Abdulrahman, 50, who has worked at the station since the late 1970s.

Outside, near the tracks, a banner in red and blue on a white background speaks of the present with these words, written in Arabic: “The Iraqi Railways supports the Iraqi Army against ISIS and terrorists.”

Sitting in the cafe car of the new train on a recent evening at the outset of an overnight trip to Basra, Ali Abdul Hussein, a rail worker for 24 years, recalls the old bar car, where the favorite drink during the times of rule by Saddam Hussein’s secular, but brutal, Baath Party was Grant’s whisky. There is no booze available these days on the train — nor at the station, where it once flowed freely in the V.I.P. room and in the officers’ saloon — a reflection of the religious mores that have dominated Iraqi life since 2003.

As for Mr. Hussein, he had his own train, which now sits in a railroad graveyard in an overgrown field near the station. Partially looted after the American-led invasion, it stands as a remnant of a different era.

Salam Hamid, 54, a railway worker with more than 30 years of service, showed a visitor around and shared a story of the time he was working as a technician and rode with Mr. Hussein to Mosul in the 1980s.

The day was hot, and the air-conditioner in the dictator’s cabin — which Mr. Hamid was responsible for maintaining — broke down.

One of Mr. Hussein’s aides, he recalls, said to him, “Saddam is saying it’s hot in here. Get it fixed.”

“I was really afraid,” he said. “Maybe he would just put a bullet in my head.”

Luckily, he got it fixed.

As the country is being pulled apart by the Islamic State insurgency, the men of the railways are dreaming of knitting it back together.

In his office at the station, Hamid Ali Hashim, a project manager, lays out a map on a table and traces his finger from Jalawla in the northeast, a city that has seen fierce fighting against ISIS militants, to Sulaimaniya in the Kurdish north, and across to Mosul. It is one piece of an ambitious, $60 billion rail project that at this stage feels aspirational at best — one that Mr. Hashim said, “would mean all the villages and cities in Iraq would be linked.”

“This,” he said, with a degree of optimism rare in Iraq these days, “is the goal.”

“I used to stand there waiting for a girl I liked,” he said. “I would go stand and wait for her and smile at her.”

The girl became his girlfriend, but they never married, and he still misses her.

“Her father was a high-ranking officer, and they refused because they were wealthy and I came from a poor family,” he said.

With just one departure daily, the station is mostly empty. But Mr. Shiekhly says that in his mind’s eye he can still see the girl, and everything else that once made the station such a special place to him: a nice restaurant over there; groups of men playing backgammon and dominoes; the officers’ lounge that was, he recalls, “beautiful and full of wood.”

The station itself is a time capsule. The ticket booths in the circular room are identified by destinations long out of reach to passenger trains.

One sign reads, “Booking for Mosul Train.” Another booth is where passengers once bought tickets to Turkey, Syria and Anbar Province.