The journey traverses the landscapes of mountain peaks, ice rivers, glaciers and vast open green plains where herds of yaks, gazelles and wild donkeys graze. The train occasionally stops (not sure if this is genuinely for a photo/animal stop or a rest for the driver). It is said that the sky is bluer and the clouds whiter here than anywhere else.

The line is designed for travel at speeds of 100 km/h on frozen ground to 120 km/h on non-frozen ground. The cabins are supplied with oxygen because of the thin air at the high altitudes and the windows have ultra-violet filters to keep out the sun’s glare. Cooling pipes are used to ensure the ground remains unfrozen.

Tickets can only be purchased 10 days in advance so are hard to get. That is not good for tourists wishing to plan their trip so you need to have a plan B. (The ticket costs only CNY¥ 389 (£26) for hard seat, CNY¥ 813 for a lower hard sleeper or CNY¥ 1,262 (£84) for a lower soft sleeper). There is a restaurant car that seats 45 people and serves basic food. Shared toilets and open area washbasins are at both ends of the carriages and there are no showers.