After decades of highly complex engineering work and billions of dollars in investment, India has finally connected the Himalayan region of Kashmir by rail to the rest of the country.

The train link, which was officially inaugurated on Friday, fulfilled a dream dating back to the British colonial era. Indian officials called it a transformative leap for the restive region after overcoming physically and politically treacherous terrain to build the railway. But many Kashmiris see the project less as a lifeline and more as an effort to entrench the central government’s control over Kashmir.

The formal opening of the rail connection had been repeatedly delayed, most recently because of a terrorist attack in late April on the Indian-administered side of Kashmir, which set off days of deadly conflict between India and Pakistan.

The new 170-mile line, known as the Udhampur-Srinagar-Baramulla rail link, was built at a cost of about $4.4 billion through some of the world’s most breathtaking landscapes. It includes one of the world’s tallest railway bridges and a nearly seven-mile-long tunnel through a mountain range.

Indian officials say the rail line will help Kashmir share in India’s steady economic growth, and improve connectivity between Kashmir and the rest of India. Until now, the only land connection was a single road that is frequently blocked by snow during the winter.

“This will change everything,” said Naveed Hassan, a 28-year-old entrepreneur. “Tourists can come directly from Delhi now. Our businesses will grow.”