NEW DELHI, April 10 (Xinhua) -- The state-owned Indian Railways has issued a rare public apology for a freak incident in which 22 coaches of a passenger train travelled backward for nearly 10 km without an engine in the eastern state of Odisha last week.

"The incident is an isolated one of staff negligence that is sincerely regretted by the Indian Railways. While the concerned staff has been suspended and a high-level probe has also been ordered, the IR (Indian Railways) remains committed to ensuring highest levels of safety in train operations," the Indian Railways said in a statement.

The incident took place late Saturday night after the engine of Ahmedabad-Puri Express was detached at Titlagarh station in Odisha for attachment at the other end of the train.

India's Railway Ministry has already suspended seven officials in connection with the incident.

A senior official said Tuesday that the apology came to instill confidence in the minds of commuters, given the railways is the lifeline of India. "It's a rare apology by the Indian Railways, but it shows the mindset is changing with times," he added.

The state-owned Indian Railways is one of the world's largest train networks, criss-crossing the country from north to south. It operates some 9,000 passenger trains and carries nearly 23 million passengers every day.

However, train disasters are quite common in India as much of the colonial-era rail infrastructure is out of date. A number of people are killed in train accidents, mostly derailments, across the country every year.

In February this year, the Indian Railways had decided to sack in one go some 13,000 railway employees in a move aimed at sprucing up its performance and giving encouragement to sincere staffers.

In 2015, Indian Prime Minister Narendra Modi's government pledged 137 billion U.S. dollars over five years to modernize and expand the railways.