Tourists have returned to brave the six-hour journey on the famous Khyber steam safari train from Peshawar, Pakistan to the border with Afghanistan.

Owen Bennett-Jones: Many of the invaders have left a cultural mark behind

The US missile strikes last year against the Afghanistan-based Saudi dissident Osama bin Laden provoked a tourist slump on the safari train and the service was forced to cancel.

According to Zahoor Durrani, founder of the Khyber Steam Safari: "[The strikes] created a kind of apprehension among the international travellers and tourists who believed it was unsafe. They thought there would be a second missile or a retaliation from across the border. That really damaged our tourism."

British legacy

It took 40 years for the railway to conquer this mountainous, rugged territory. The British built it to carry men and munitions to the Khyber Pass.

Two engines, one pulling, the other pushing, climbed through the lawless, tribal territories.

Colonialist legacy: It took 40 years for the British to conquer the terrain

Now, foreigners need special permission to travel to the Khyber Pass. Many who take the train are ex-patriots - aid workers and foreign diplomats who work and live in Pakistan.

From the safety of their carriage they can see parts of the country which over the centuries have proved too rugged for large armies to reach.

Throughout, the Khyber tribal agency has governed its own affairs, while the writ of the Pakistani Government extends just to the main roads.

As you approach Afghanistan, you can see thousands of smugglers hidden in the mountains, lugging anything from glasses to televisions from Afghanistan to Pakistan - a trade which carries on in times of war and peace.

Smugglers lugging TV's climb tracks that armies failed to reach

But visitors are more easily put off and stayed away after the missile strikes.

The Khyber Pass has seen many invaders come and go, each leaving something of their culture behind and creating a diversion for visitors at one of the many stops the train makes as it makes its ascent.

Tim Ekin, a tourist, said: "It's a romantic place and it's got so much history. If you're based in Pakistan or just visiting, it's one of the places on the map to say that you've been to."

Six hours after the journey begins you are at the end of the line, and gazing over the famous gateway to Afghanistan and central Asia beyond.