Beacon Hill Tunnel is a tunnel

Tunnel

A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...

 in Hong Kong

Hong Kong

Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...

, China

People's Republic of China

China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...

 on the original Kowloon-Canton Railway

Kowloon-Canton Railway

The Kowloon–Canton Railway refers to a railway network in Hong Kong which is now combined with the MTR railway system, comprising rapid transit services, a light rail system and feeder bus routes within Hong Kong, and intercity passenger and freight train services to the rest of China...

 from Kowloon

Kowloon

Kowloon is an urban area in Hong Kong comprising the Kowloon Peninsula and New Kowloon. It is bordered by the Lei Yue Mun strait in the east, Mei Foo Sun Chuen and Stonecutter's Island in the west, Tate's Cairn and Lion Rock in the north, and Victoria Harbour in the south. It had a population of...

 to Canton

Guangzhou

Guangzhou , known historically as Canton or Kwangchow, is the capital and largest city of the Guangdong province in the People's Republic of China. Located in southern China on the Pearl River, about north-northwest of Hong Kong, Guangzhou is a key national transportation hub and trading port...

, linking Kowloon Tong

Kowloon Tong

Kowloon Tong , formerly Kau Lung Tong, is an area in Hong Kong. Within New Kowloon, it is administratively divided by Kowloon City District and Sham Shui Po District...

 to its south and Sha Tin

Sha Tin

Sha Tin, also spelled Shatin, is an area around the Shing Mun River in the New Territories of Hong Kong. Administratively, it is part of the Sha Tin District.-Geography:...

 to its north, between Kowloon Tong and Tai Wai stations. Services through the tunnel are provided by MTR

MTR

Mass Transit Railway is the rapid transit railway system in Hong Kong. Originally opened in 1979, the system now includes 211.6 km of rail with 155 stations, including 86 railway stations and 69 light rail stops...

.

History

A team of surveyors

Surveying

See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...

 were commissioned to survey the route for the KCR British Section in 1905. Two routes have been proposed:

1. Construction of a tunnel 1.5 mile (2.4 km) long through Beacon Hill
   Beacon Hill, Hong Kong
   Beacon Hill is a hill in the Kowloon Tong area of Hong Kong's Kowloon peninsula. It is the 65th highest hill of Hong Kong. It is 457 m tall.Beacon Hill is located within the Lion Rock Country Park.-Name:...
   
    then following the west coast of Tolo Harbour
   Tolo Harbour
   Tolo Harbour , or Tai Po Hoi is a sheltered harbour in northeast New Territories of Hong Kong.-Geography:Tide Cove aka...
   
   
2. Routing through Western New Territories
   New Territories
   New Territories is one of the three main regions of Hong Kong, alongside Hong Kong Island and the Kowloon Peninsula. It makes up 86.2% of Hong Kong's territory. Historically, it is the region described in The Convention for the Extension of Hong Kong Territory...
   
    and Castle Peak Bay
   Castle Peak Bay
   Castle Peak Bay is a bay outside Tuen Mun. Tuen Mun River empties into the bay. In the past, large amount of Tanka fishermen harboured at the bay....
   
   

Although option 2 was less of an engineering challenge, the overall route was longer, and passed through less economically

Economics

Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...

 active areas; therefore option 1 was selected. Works on the 35.4 kilometres (22 mi) railway

Rail transport

Rail transport is a means of conveyance of passengers and goods by way of wheeled vehicles running on rail tracks. In contrast to road transport, where vehicles merely run on a prepared surface, rail vehicles are also directionally guided by the tracks they run on...

 to the border started early 1906. Construction of the tunnel, referred to as Tunnel No.2 in the plan (since it was the second tunnel starting from Kowloon), was the greatest engineering

Engineering

Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

 project in Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 of its time.

The tunnel opened with rest of the line in October 1910, together with four smaller tunnels. It accommodated a single standard track with a standard gauge

Standard gauge

The standard gauge is a widely-used track gauge . Approximately 60% of the world's existing railway lines are built to this gauge...

 of . It has, however, been notorious for its fume problems throughout its operating life; due to its steep gradient

Slope

In mathematics, the slope or gradient of a line describes its steepness, incline, or grade. A higher slope value indicates a steeper incline....

 of 1%.

A double tracked, electrified

Railway electrification system

A railway electrification system supplies electrical energy to railway locomotives and multiple units as well as trams so that they can operate without having an on-board prime mover. There are several different electrification systems in use throughout the world...

 tunnel was built to 30 to 40 metres west of the original one as part of the modernisation of the KCR. Work started in 1978, and was completed by 1981, the railway now the MTR East Rail Line. The original tunnel was closed upon completion of the new tunnel, and is now occupied by a 750 mm diameter town gas pipeline.

First tunnel

• single track.
• 2.2 km long.
• horseshoe shaped, 5.2 metres width by 5.8 metres high above rail level.
• up to 427 metres below ground.
• tunnel lining upgraded in 1982 and 2008.

Second tunnel

• double track.
• 2.3 km long.
• horseshoe shaped, 11 metres width by 9 metres high.