The most important early step in designing a tunnel and devising the conveyor belt installations, tunnel boring machines and supporting pieces is a matter of purpose; why is the tunnel being constructed and what benefits does it provide against its potential short-term and long-term disruptions?

This is at the core of the legal challenges surrounding the A303 Stonehenge tunnel, where the benefits of reducing congestion and cutting travel times by an hour are offset by the potentially irreversible damage to one of the most important historical sites in the UK.

However, in many cases, the benefits of the tunnel are so significant and impossible to ignore that the tunnel has to be constructed whenever it is feasible to do so, and nowhere is this possibly more evident than with the Lowari Tunnel, planned in 1974 and completed in 2017.

Passing The Lowari Pass

Before 2017, people attempting to travel from Peshawar to Chitral in Pakistan had few options, all of which took the better part of a day by car and none of them were particularly ideal.

The most popular of these is the Lowari Pass, a mountain road that crosses the Hinju Raj mountains, one of just four mountain passes that enter the northernmost region of Pakistan.

Because of its elevation of over 10,000 ft, snow builds so heavily between November and May that the road itself is closed for roughly half a year.

Avalanches are common, abrupt and exceedingly deadly, and this is an inherent risk of travelling the mountains at any point besides the height of summer.

The only other route to reach Chitral is to travel down the Kunar River to Jalalabad in neighbouring Afghanistan, a route that is inherently dangerous and potentially lethal for very different reasons.

The UK Government advises against all travel to Afghanistan, and the security and safety situation has been extremely volatile for at least two decades.

Because of this, the Lowari Pass remained the most popular route despite its inherent dangers but plans to create a solution to the dangers were proposed as early as 1975, just two years after the drafting of the Constitution of Pakistan.

The original proposal was for a railway tunnel between Dir and Chitral, but a year later the plans were halted due to a lack of funding, and it would take another three decades before construction would resume in 2005.

The work, part of a slate of mega highways projects under Pervez Musharraf, would regularly see delays, changes in the design and concerns about the safety of the tunnel, leading to the project stopping in 2009, the year it was meant to have been completed.

The need for the tunnel was such that the plans were modified in 2013, and finally completed in 2017, 42 years after it was originally designed.

The benefits were immediate; not only did the 6.5 miles of tunnel cut travel times by seven hours, but they allowed travel into Chitral during the winter, avoiding the need to travel to Afghanistan to access the region during half of the year.

The effects of this access led to the development of an Economic Zone in the region and a transformation in the area’s fortunes.