(CNN) Another deadly train derailment killed dozens in India on Saturday -- the latest in a string of fatal accidents to strike the so-called "lifeline of a nation."

At least 39 people were killed and 50 seriously injured after the train derailed in the Indian state of Andhra Pradesh, J P Mishra, chief public relations officer of East Coast Railway, told CNN.

He said a total of seven coaches left the tracks near Kuneru station.

"Besides the engine, the luggage van, two general coaches, two sleeper coaches, one AC three tier coach and an AC two tier coach derailed," Mishra told CNN affiliate News 18. The cause was unknown.

The derailment comes only a few months after India's deadliest rail accident since 2010 -- a tragedy that once again pulled to the fore the issue of how the country's vast rail network is funded and maintained.

Last November, at least 148 were killed in the early hours of Sunday morning when a packed train traveling from the central city of Indore to Patna in the north east went off the track.

"All of a sudden there was a massive jerk," said one survivor, Ravindra Pathak at the time. "Our heads collided with the roof of the carriage."

In the wake of the accident, former Indian rail minister Dinesh Trivedi told CNN the Indian railway system needs a "generation change."

"The present system has outlived its utility," Trivedi said.

Lifeline of a nation?

Often called "the lifeline of a nation," India's extensive rail network runs 12,000 trains a day and the full-length track could circle the globe over one and a half times.

It carries more than 23 million passengers daily, the equivalent to moving the entire population of Australia, and connects 8,000 stations across the subcontinent.

It's also one of the oldest train networks -- built roughly 163 years ago by the colonial British government -- and is chronically underfunded . The system is often criticized for being inefficient, overburdened and unsafe.

Photos: Deadly train derailment in northern India Rescue personnel work at the site of a Patna-Indore Express passenger train that derailed in Pukhrayan, India, near Kanpur, on Sunday, November 20. More than 100 people died in the crash. Hide Caption 1 of 7 Photos: Deadly train derailment in northern India Onlookers and survivors gather next to wreckage of the train that derailed on November 20. Hide Caption 2 of 7 Photos: Deadly train derailment in northern India A survivor of the derailment looks for his belongings in the wreckage. Hide Caption 3 of 7 Photos: Deadly train derailment in northern India Indian rescue workers search for survivors in the wreckage. Hide Caption 4 of 7 Photos: Deadly train derailment in northern India Rescuers lift one of the 14 coaches in the 23-car train that rolled off the track. Hide Caption 5 of 7 Photos: Deadly train derailment in northern India With her uncle at her side, a 2-year-old passenger of the derailed train gets admitted to a hospital in Pukhrayan. Hide Caption 6 of 7 Photos: Deadly train derailment in northern India A National Disaster Response Force employee works at the derailment site in Pukhrayan. Hide Caption 7 of 7

"The system is over stretched, overstressed and has a direct impact on the safety of the operations in running trains," says Debolina Kundu, associate professor at the National Institute of Urban Affairs.

She says that, to earn revenue, new trains are continuously being introduced, but proper care is not being taken to replace the "over-aged" rolling stock. And the problem isn't just with the trains themselves, but how the tracks are being maintained.

"Most of the bridges and culverts [tunnels] have outlived their lives and become weak."

She told CNN that before introducing more trains and increasing the frequency of services, in her view, there should be a proper survey of "the capacity of the infrastructure to bear the additional stress."

"Priorities of investment have to be made," she says.

Shocking numbers

Accidents are all too common.

According to data released by the National Crime Record Bureau , a staggering 27,581 people died in rail accidents in India 2014, many of whom perished after crossing the vast swathes of tracks that border communities, homes and villages.

Local people regularly cross the lines where it's most convenient and, even when there is a manned crossing, duck under the barriers.

Experts argue there's a need for an education drive on where and how the population should cross the tracks safely, but the reality is, with so many people living so close to the tracks, they're facing an uphill battle.

Comparatively, the percentage who die from derailments is relatively small.

And while the number of train accidents seems high compared to other countries, there has been a steep drop in serious incidents since in the early 1990s.

"The number of consequential train accidents decreased from 530 during 1991-92 to 131 during 2011-12," says Kundu.

"The continuous reduction in the number of train accidents per million train kilometers is indicative of sustained improvement in safety performance," she stresses.

Boys walk to school over railway tracks close to the Nizamuddin Railway Station in New Delhi, India.

'Under-investment'

A major contributor to the system's financial woes are heavily subsidized fares, which the government has shied away from increasing.

While these fares make the system accessible for millions of Indians that rely on it, the freight and goods network ends up subsidizing the passenger facilities, which experts argue leaves little left for maintenance.

Japan and Google announced major investments last year , aiming towards India's first high-speed rail link and the introduction of Wi-fi hotspots across hundreds of stations.

And in a White Paper issued in February last year, Indian Railway Minister Suresh Prabhu readily admitted the financial shortfall thus far.

Photos: A boy peers out of a window while his family travels by train in the southern Indian state of Kerala. Photographer Sara Hylton spent months traveling India's vast railway system. She said "the thing that stands out to me most about Indian trains is their intensity. ... Their scope and their culture is so much more intense than what I experienced on other trains. Everything feels multiplied." Hide Caption 1 of 12 Photos: A view of the train station in Dibrugarh, one of the main train stations in the northeastern state of Assam. India's first passenger train began running in 1853, and today the country's railway system is one of the largest in the world. Hide Caption 2 of 12 Photos: A mother rests with her baby on the third and final day of their train trip to Kerala. Hide Caption 3 of 12 Photos: A view from a train near Bhubaneswar station, the capital of the eastern state of Odisha. Despite being the second-poorest state in India, Odisha received a 30% increase in the Indian Railway budget to expand its transport system for 2016-17, Hylton said. Hide Caption 4 of 12 Photos: Passengers sit in the waiting area at Shoranur Junction, a railway station in Kerala that stands at the intersection of four railway lines connecting the east, west, south and north of the country. Hide Caption 5 of 12 Photos: A vendor shows textiles to passengers on India's longest train, the Vivek Express. Hide Caption 6 of 12 Photos: A passenger shaves before his train arrives at his final destination in Kerala. Many passengers spend several days on the train with no access to showers, and they must share common spaces such as a bathroom. Hide Caption 7 of 12 Photos: A laborer works along the railway in rural Punjab. Hide Caption 8 of 12 Photos: Workers load goods onto a train at Guwahati station in Assam. Hide Caption 9 of 12 Photos: Ravi, a food vendor at the Kota Junction train station in Rajasthan, sells bottled water and fried Indian snacks to travelers. Food options vary by state, particularly from north to south, Hylton said. Hide Caption 10 of 12 Photos: PP Singh looks out the window on the Kochuveli Express. Unlike many other Indians, Singh and his family had the luxury of traveling in second AC, which offers bedding, air conditioning and more space and privacy. Hide Caption 11 of 12 Photos: A view of the Arabian Sea as a train passes through the southern coastal state of Goa. Hide Caption 12 of 12

"Indian Railways has suffered from considerable under-investment during the last years," he wrote . He acknowledged that customer satisfaction and technological improvements had suffered as a result.

"Investments in safety have also been insufficient," he added.

As part of the budget in March last year, Indian Prime Minister Narendra Modi's government promised record investments aimed at improving safety, security and the quality of service.

But the latest crash will serve as a blunt reminder of the challenges facing his government in their attempts to deliver on this pledge.

"Despite its problems, Indian Railways is not down and out," Prabhu optimistically wrote in his White Paper last year.

"Indian Railways is perched on a precipice but is capable of flying off and attaining great heights."