Cross Harbour Tunnel proposed, construction engineering expert interviewed in 1947 newspaper article
IDJ has kindly sent an article published in the The Hongkong Telegraph on 25th January 1947 on the subject of constructing a cross harbour tunnel. The first cross harbour tunnel linking Hong Kong Island and Kowloon was actually opened on 3rd August 1972, though there were proposals for a bridge pre-WW2, see articles linked below.
HF: The copy IDJ sent was not entirely legible so I decided to retype the whole article.
HARBOUR TUNNEL FOR H.K. ADVOCATED
Practicability Emphasised by Engineering Expert
One of the most practical propositions the Hongkong Government can tackle at the present time, both from the financial and constructional point of view, is a cross harbour tunnel. This, the “Telegraph” learned from an engineering expert this week, who, in an exclusive interview, expressed the opinion that the building of a tunnel would be relatively easy, and its construction costs could be recovered by tolls in ten years.
The question of a submarine tunnel linking Kowloon with the island has long been a subject for debate. Its feasibility was explored by government before the war, although no definite official action has been taken on any suggestions then advocated.
Which is why the “Telegraph” asked the following questions and publish the answers given by an expert in constructional engineering who has made a close study of the question.
- Is there any need for improved transportation facilities in Hongkong? Yes, I think so. The present congested conditions of travel across the harbour are only in part due to the destruction of ferry facilities during the war. They are also due to the increased total number of passengers using the ferries these days. Then there is the question of improving the ferry services. Apart from the question of getting quick delivery of the necessary vessels, engines and so on, improvement will cost a great deal of money. It is part of my belief that such money could be better invested in a cross harbour tunnel thus taking advantage of the war destruction to repair and improve transport facilities. Apart from the passenger ferries, the vehicular ferry was, as reported by Sir David Owen in 1941, was rapidly reaching saturation point and he recommended the construction of a second service [?] of the naval dockyard. Here again, the money thus to be spent could be diverted to the cost of a tunnel.
- What are the possible alternatives? Ferries, a bridge and a tunnel. The ferries are relatively slow, limited in capacity (especially for vehicles), are subject to weather vagaries (for example typhoons), are expensive in maintenance, both in vessels and piers.
A bridge is feasible but a difficult engineering problem. Requirements would include sufficient clearance for passenger liners, adequate stiffness and strength to withstand typhoons; a reasonable gradient would imply access roads at some height above the shore on each side. This would also probably be the most costly of the three alternatives.
A tunnel is also feasible, by one or the other well established engineering methods. It has the advantages of a minimum cost of upkeep, immunity against typhoons, and the accomodation of the cross harbour services such as water supply, telephone and power cables, which can be serviced ‘in the dry’.
- Assuming a Harbour Tunnel was built, what would be the Engineering Methods Adopted? It is known that the harbour bed in the strait between Victoria and Tsimshatsui is “soft” earth and not solid rock at the levels at which a tunnel would have to be constructed. Tunnel methods depend on the type of soil encountered. In soft earth, two methods are available; (a) Shield, with or without compression, and progressive lining; (b) cut-and-cover in which a trench is prepared in which the tunnel is constructed, the level of the soil being made good by levelling.The second method is the one most probably best suited to Hong Kong since by this method it is not necessary to go so deep. Several tunnels in America and Europe have been successfully built by this method, which can be briefly described as follows: Sections of the tunnel are built up on shore, either in steel or reinforced concrete, the ends sealed with temporary bulkheads so as to be airtight; the . sections are then launched and floated into position. Meanwhile a trench has been dredged, deep enough to accommodate the tunnel section with due allowance for a safety depth of cover, and a bed prepared for the sections to lie on. When the sections are accurately located, they are lowered into position in the trench and joined to the preceding section. When the tunnel has been laid, and joined, with all joints watertight, the water inside is pumped out, and the internal work is completed.
- What do you propose to do about the approaches to this tunnel? This section of the tunnel would be on a slope down from each shore, with a level section in the middle; but at each end the tunnel would cross the shore at some depth. To connect this with the normal street level, a considerable length of gradual rise is required, but this need not necessarily be straight. It can also be curved into a helical shape, such as used in multi-storey garages in America and Europe. Such a “spiral” ramp could be situated close to the shore and would occupy relatively little of the expensive waterfront. By reclaiming the necessary areas, it would be quite feasible to arrange a direct access by tunnel from the lower end of Nathan Road in Kowloon to the Praya in the vicinity of Statue Square. In this connection it would be an advantage if the railway sidings along Salisbury Road were moved elsewhere.
- And what about ventilation? Tunnels under harbours and rivers normally require special ventilation. This is done by installing air ducts and pumping fresh air into the tunnel from one or both ends by means of large fans; the flow is often assisted by having other air ducts, connected by suction fans, and thus exhausting the foul air from the tunnel. The use of a tunnel by motor vehicles would produce both carbon dioxide, water and smoke, in addition to which the high humidity would make an unpleasant atmosphere. But this is cleared by forced ventilation, the air being taken in at the top of towers at each terminal.
- And drainage? The drainage of tunnels presents no special problem, except, of course, pumps have to be used to raise the water to the ends of the tunnel.
- Then there is lighting? The interior of a tunnel can be well lighted, the intensity of light in the latest tunnels being graduated to avoid a sharp contrast from outside conditions when entering or leaving. Both florescent and the sodium lighting have been installed in such tunnels, the effect being enhanced by lining the tunnels with light reflecting surfaces such as tiles, glass, and other similar materials.
- Next comes that all important question, cost? I admit it is difficult to give any reliable estimate of cost at the present. The cost would depend very considerably on the method and shape adopted, and since it would take several years to complete, prices, both of labour and materials are likely to change during the construction of the tunnel. A previous estimate of cost, however, was HK$10,000,000. In addition to this, there are operating costs, such as power, costs of ventilation, lighting, drainage, maintenance, and the cost of collecting tolls.
- How then, can a tunnel be made financially practicable? It would be necessary, at least for some years, to charge a toll for using the tunnel. If this were kept at the same charges now paid for transportation by ferry I estimate that the capital cost could be recovered within ten years, assuming that the total traffic remains at its present volume. From experience with other tunnels, and indeed all facilities provided for public use, it is common to find that improvement in facilities leads rapidly to an increased use, so that the revenue is likely to be greater than estimated.
- How do you think a harbour tunnel should be financed and operated? The construction and operation of a tunnel should be undertaken by government; a suggested method is by a Public Trust, such as the London Passenger Transport Board, with a charter from government. Finance would be provided by loan, the existing companies being invited to become shareholders so that their resources and personnel could be absorbed in the Board.
- What is your estimate of the capacity of a harbour tunnel? The total length of the tunnel would be about a mile in all, so that few foot passengers would be expected to use it. Its use by buses, or electric trolley buses is quite feasible, and such transport would facilitate the collection of tolls which would be paid by the bus companies. Most vehicular tunnels are traversed by motor cars at a considerable speed (the Holland Tunnel in New York is sign-posted ‘Minimum Speed 45 mph) but even assuming a speed of 30 mph and 50 yards between vehicles, each lane would be able to pass 1,000 vehicles per hour. The ability to transport goods by truck without additional handling costs would induce much commercial and industrial lorry traffic to use the tunnel, and the capacity of the tunnel would tend therefore, to be utilised to a profitable extent. However, I feel it would be many years before the full capacity is exceeded, even at rush hours. The engineering expert said that, after a long and close study, he was convinced, both as to the necessity and practicability of a cross harbour tunnel for Hong Kong. He felt that it was a subject that should engage the attention of the public.
- The Telegraph thinks so, also, and invites readers to contribute their ideas, if only to government a gauge of public opinion on this subject.
This article was first posted on 30th June 2020.
Related Indhhk articles:
- Cross harbour road tunnel – link to planning of Shing Mun reservoir, late 1920s?
- Sir John Douglas Clague – connected to a wide array of Hong Kong businesses and lobbyist for the first Cross Harbour tunnel
- The Cross-Harbour Tunnel – Part 1 Gestation
- The Cross-Harbour Tunnel – Part 2 Construction
- Cross Harbour bridge proposals – road 1901, tram 1920s
- Kowloon Trams – the when, the where but not the why not…and proposed cross harbour tram bridge!
- Proposed iron bridge connecting HK Island – Kowloon pre-1921