It's often described as India's lifeline, transporting 23 million people across the vast South Asian country each day.

India's rail network, the world's third largest, operates more than 12,600 trains carrying passengers and cargo along 115,000 kilometers (71,000 miles) of track. With more than 1.4 million employees, it is the country's largest employer.

But not all is well with state-owned Indian Railways, as was highlighted Sunday when 14 packed cars on a passenger train skidded off the tracks, killing at least 148 people in the northern state of Uttar Pradesh, after two more victims died of their injuries Tuesday.

For years, it's been clear that the much-romanticized legacy of British colonial rule, built more than 160 years ago, is badly hobbled by funding shortfalls, aging tracks, outdated signaling and communications systems and a traffic volume that has pushed these systems beyond their limits.

The weekend's deadly train tragedy, the cause of which is under investigation, has focused attention on how India can restore both efficiency and public confidence in its railways.

India's economy has boomed in recent decades, and dozens of private airlines have emerged to serve the growing upper middle class. But for tens of millions of Indians living in the hinterlands or unable to afford air travel, trains are their transportation lifeline.

It can be a dangerous lifeline. India's crime records bureau says that in 2014, the latest year for which figures are available, more than 25,000 people died in railway accidents that ranged from travelers falling from the roofs of moving trains to train collisions. In 2012, a government safety committee said about 15,000 people die every year trying to cross train tracks, which it referred to as "a massacre."

On Sunday, hours after the accident in northern Uttar Pradesh state, Railway Minister Suresh Prabhu announced an investigation and said anyone found guilty would be strictly punished.

But blame should also fall on successive governments and railway ministers that have starved the organization of funds, denying it key resources to upgrade critical equipment and pushing it to the brink of bankruptcy, said former Railway Minister Dinesh Trivedi.

Trivedi said the railways need 200 billion to 250 billion rupees ($3 billion to $3.8 billion) simply to replace old equipment.

Instead, the government approved a mere 32 billion rupees ($485 million) in the 2016 budget.

"Therefore, the much-required replacement of old assets is postponed — knowingly compromising safety," Trivedi said.

Critics of Prime Minister Narendra Modi, who came to power in 2014, say his government has concentrated too much on high-publicity rail plans, like wanting to introduce high-speed "bullet" trains, instead of boring but necessary upgrades and repairs.

"When we can barely manage train speeds as they are at present, such talk of building bullet trains on which billions of dollars are to be spent is illogical," said Basudev Acharya, a former lawmaker who headed a parliamentary committee overseeing railway operations.

"What needs immediate fixing is to ensure adequate funds for maintenance of the existing stock and, most importantly, filling up vacancies among safety workers," Acharya said.

Railway workers say decades of funding crunches have taken their toll. Passenger trains in India run at slow speeds, averaging around 50 kilometers (30 miles) an hour, while freight trains are even slower, averaging half that.

"Even at such low speeds we have a high number of deaths in railway accidents. Can you imagine the toll if the speed were any faster?" said N.B. Dutta, a railway locomotive driver and president of the All India Loco Running Staff Association, a train operators' trade union.

On Sunday, four children were killed by an intercity express train while crossing the tracks in the northeast state of Assam.

Dutta spoke of crucial safety-related positions that remained vacant, placing rail conductors under stress.

"We work four to five nights consecutively," though rules say conductors should only work two nights in a row, said Dutta.

His colleague, C. Sunish, said the stress can be immense, with drivers trying to catch sleep in railway station waiting rooms after 12- to 14-hour shifts.

Sunish said successive governments have failed to implement the recommendations of state-appointed committees on rail safety. "Every time there is an accident, the minister will order an investigation, but the outcome remains the same. No correctional measures are taken," he said.

Although the investigation into Sunday's train derailment is still underway, railway experts said it was most likely caused by tracks that had deteriorated over the years.

Most railway tracks are checked every day with ultrasonic detectors that can spot changes in track conditions. This is followed by visual inspections, railway managers say.

But with many jobs vacant, some lapses in checks should be expected, they warned.

Running the railways in India, regulating the budget, ensuring safety and managing rail traffic is done by a government-appointed Railway Board. Several former members of the panel said that although India's rail safety record has improved over the past few years, inadequate resources and political and bureaucratic apathy continue.

"Every time there is an accident or a derailment, we can't have a knee-jerk response," said Sunil Kumar, a retired safety adviser of the Railway Board, calling instead for a steady infusion of funds to replace, repair and restore railway infrastructure.

In 2015, Modi promised a staggering $137 billion to be invested over five years to revamp the railways.

Rail Minister Prabhu said the money would transform Indian Railways. Almost two years later, there's no word on how much of that money has reached the railroad.


Follow Nirmala George on Twitter at twitter.com/NirmalaGeorge1