The company has added more comfortable seats and beds and cleaned up toilets on what it calls "high-quality" trains serving Lao Cai and the central beach town of Vinh.

It has also launched shuttle buses to take passengers from Lao Cai to Sa Pa and from Vinh to Cua Lo Beach.

Sa Pa is one of the most famous towns in Viet Nam, becoming even more popular during summer thanks to its cool climate.

In the past most tourists travelled to the town by train from Ha Noi, but since the Noi Bai-Lao Cai Expressway opened in September 2014, many find the five-hour bus ride more appealing than the eight-hour trip on the train.

Train tickets from Ha Noi to Sa Pa now cost up to $20, but the company said summer vacationers would get 10-20 percent discounts.

In the south, the HCM City-based Sai Gon Railways Company is scheduled to launch high-quality trains between Nha Trang and Hue, three months after the launch of a HCM City - Nha Trang service.

Trains accounts for 1.14 per cent of passengers transported in Viet Nam, compared to 96 percent by road and 2 percent by air, according to figures from the National Statistics Bureau.