Higham & Strood Tunnels

Now two separate tunnels, the pair once formed a single continuous bore through a chalk ridge on the Thames & Medway Canal. The origins of this canal, much of which remains in existence to this day, can be traced back to 1799. It was at this time that consideration was given to the possibility of creating a new passage between the Thames and Medway Rivers for vessels, avoiding the need to circumnavigate the Hoo Peninsula. The project was pioneered by engineer Ralph Dodd, who produced a fourteen-page report detailing a canal between Gravesend and Strood. This was planned to be 6-miles, 7-furlongs, and 2-chains in length, and reduce the Gravesend to Strood distance for vessels by about 30-miles. The scheme received its Act of Parliament on 16th May 1800, and the ‘’Thames & Medway Canal Company’’ was incorporated, with the powers to raise £40,000 (£2,160,000 at 2008 prices) in shares of £100 value. In addition, should further sums of money be required for the canal’s completion, the company was permitted to raise another £20,000, either through mortgaging the infrastructure or by the issue of more shares.

Act of 16th May 1800: An Act for making and maintaining a navigable Canal from the River Thames, near to the town of Gravesend in the county of Kent, to the River Medway, at a place called Nicholson’s Ship Yard, in the parish of Frindsbury, in the said county; and also a certain collateral Cut from Whitewall, in said parish, to the said River Medway.

Work soon commenced on the Gravesend portion of the canal, and the major feat of engineering of the scheme was to be a tunnel through a chalk ridge, the latter blocking direct access to the shipyard at Strood. A bore 2-miles 1-furlong in length was required, but the sheer work involved prompted the company to alter its plans soon after completing the Gravesend to Denton section of the canal, in 1803. Dodd was joint engineer of the project with one Ralph Walker, and the latter proposed a deviation in the canal, which negated the requirement of a tunnel. The revised plans required a longer canal, 9-miles 1-chain-long, in order to avoid the ridge, and similar to the earlier proposals, this would traverse the natural level of the Gravesend Marshes. A second Act was passed for the new plans on 5th June 1804, and Walker estimated that a cost of £98,147 and 10 shillings (£6,900,000 at 2008 prices) would be incurred by making the deviation. This sum would, as per the original amounts of the 1800 Act, be raised by another shares issue.

Progress on the project stalled, seemingly because the promoters could not make up their minds on which course the canal should take; on 18th May 1810, a third Act was passed for yet another revised version of the canal plans. As a result of these changes, the independent canal company ran out of money, requiring a fourth Act of Parliament to be obtained on 17th March 1818. This authorised an additional £100,000 to be raised, either in the form of £50 shares or £100 bonds, the latter of which were secured on the company’s property. By this time, a tunnel was back on the agenda, but the scheme was now under the leadership of a new Civil Engineer, William Tierney Clark. Boring of the tunnel commenced in April 1919.

A fifth and final Act, dated 17th June 1824, authorised the canal company to raise £50,000 in the form of bonds of £1000 value each, in the endeavour of eradicating all existing debt. Should this amount prove insufficient, a further sum of £25,000 could be raised. After all the financial woes and building delays, the Thames and Medway Canal formally opened to traffic on 14th October 1824. The event was marked by a convoy of barges passing along the canal from Strood to Gravesend, and a formal dinner was held at the Crown Hotel, Rochester.

The canal started in the parish of Milton, and traversed a dead-level course across the Gravesend Marshes for over 4-miles, before meeting the chalk ridge. Basins and wharves were to be found at either end. The canal’s body tapered from 50-feet-wide at the top to 28-feet-wide at the bed, and held water 7-feet deep. Through the hill was bored a tunnel, requiring works of considerable magnitude. This was 4012-yards-long and followed a dead-straight course – light at each extremity of the tunnel was clearly visible from the opposite ends. The bore was 30-feet-wide, of which 24-feet was taken up by the canal and the remainder by a towpath. The solidity of the chalk through which the tunnel was excavated meant that no brick lining was incorporated within the bore, the arch of which rose over 15-feet above the level of the towpath. Furthermore, the tunnel was formed in sections of alternate curvatures, these being either parabolic or circular, the arches of which all coincided. The absence of a brick lining meant that even within the middle of the tunnel, there was never total darkness during the daytime, for light was well reflected by the exposed chalk layers. This was to the extent that print of a large size could still be read in the available light. Had the tunnel been lined throughout with brick, the absorption of light would have been so great that artificial illumination would have been required. The tunnel was wide enough only for the passage of vessels in one direction at a time. To ensure barges at either end of the tunnel did not both enter at the same time, a set of rigid times were drawn up. Thus, barges could only enter the tunnel at the specific times laid down, and the intervals were arranged so as to allow enough time for a vessel to cover the full 4012-yards. Barges had to enter the tunnel at the precise time; should they just miss it, these vessels had to wait until the next available slot.

Unfortunately, for an undertaking which took quarter of a century to finish, the canal did not reach the aspirations of its promoters. In 1831, it was already reported that the canal was little used, although it did witness brief bursts of traffic during the hop-picking season. Traders shipped their hops up the Medway from Maidstone, and use of the canal allowed the journey to the markets of London to be made in 24-hours. In those early years of moderate traffic flows, the tunnel soon became a bottleneck, for over two miles of the canal was single-track. In an attempt to improve this scenario of conflicting movements, it was decided to open the tunnel out approximately ⅓-mile from the Higham end. This gap was 151-yards-long, and allowed a short double-track section of canal to be instated to permit barges to pass each other. The work was completed in 1830 and as a result, produced two separate tunnels; Higham Tunnel, at 1529-yards-long, and Strood Tunnel, at 2332-yards-long.

Canals nationwide were soon overtaken in their usefulness by fledgling railways and, on 8th February 1844, the ‘’Gravesend & Rochester Railway & Canal Company’’ came into existence. Work began immediately on laying a single-track railway, of 4-foot 8½-inch gauge, on the southern side of the canal, running parallel with the latter for its entire extent. To take the railway through Higham and Strood Tunnels, the solution devised was novel: the single line was partly supported by the tow path and partly upon wooden piles driven into the canal bed. The incursion into the canal water was necessary to provide a wide enough track bed. Concerns of running trains through the tunnels prompted a strength test: Major General Paisley of the Board of Trade fired blank mortars within the bores to check for chalk falls. Whilst none occurred, and the chalk layers were confirmed as robust, Paisley advised that certain sections of the tunnels should receive additional brick layers. The Gravesend & Rochester Railway, which in fact terminated in Strood, formally opened on 10th February 1845. For the next couple of years existed the bizarre practice of trains and barges running side-by-side within the tunnels.

It is worth noting that the train fare along the Gravesend & Rochester Railway was sixpence in each direction. At 2008 prices, this equates to £2.02, which compares with the year 2010's single ticket price of £3.80 between Gravesend and Strood. Of course, cheap day return fares were not in existence in 1845, and 2010's off-peak return fare of £3.90 looks marginally favourable against those early prices! Passengers were intrigued by the tunnels, which prompted them to open the carriage doors as trains passed through the bores. Consequently, during the first week of railway operation in February 1845, several carriages had doors torn off their hinges, and some passengers nearly lost their heads. Thereafter, on departure from the Gravesend terminus, the carriage doors on the right-hand side of the train, nearest the tunnel wall, were locked to prevent opening. Should the train break down, the only way out for passengers was through the unlocked door into the canal!

On 17th June 1846, a General Meeting of Shareholders of the Gravesend & Rochester Railway & Canal Company was held at the George & Vulture Tavern, City of London. It was reported that traffic had been steadily increasing since opening and, to cope with projected growth, it would be necessary to order two new locomotives, in addition to more trucks to convey another 150 Third Class passengers. A short westward extension from the existing terminus at Denton was planned, to bring the railway closer to central Gravesend. On the advice of engineer Robert Stephenson, the rails within the tunnels were to be re-laid on earthwork. At the same meeting, the sale of the company to the South Eastern Railway was unanimously agreed amongst shareholders. The sale had been approved in principle in early March 1846, and on 24th April of the same year, the SER paid a £31,000 deposit to the independent concern. By Act of 16th May 1846, the SER formally took over the Gravesend & Rochester Railway & Canal Company for £310,000 (£22,400,000 at 2008 prices).

The SER’s North Kent Line Bill passed successfully through Parliament in July 1847, which authorised a double-track line of 53-miles, 1-furlong, and 213-yards in length. This would start at a junction with the London & Greenwich Railway at the Grand Surrey Canal, and take a course through Woolwich, Dartford, Gravesend, the Medway Towns and, finally, end at Chilham, where a connection with the SER’s Canterbury branch would be made. Work started on upgrading the existing Gravesend & Rochester Railway: the water within the tunnels was drained and the canal bed in-filled. The tunnel walls were trimmed back to ensure a double-track line could be accommodated comfortably, and the opportunity was taken to install more brick lining. Through running of regular services from London to Strood over the North Kent Line commenced on 30th July 1849. The original terminus at Denton was replaced with a new Gravesend station in the centre of town; the existing site at Strood was also replaced by new platforms on a revised alignment. Higham was the only station on the original route of the Gravesend & Rochester Railway to survive.

Recent Times

Whilst the northern portal of Higham Tunnel has for long been faced with brick, there was no such fascia on the southern portal of Strood Tunnel. Instead, the curved lining of the latter protruded out of the jagged chalk ridge, and a proper brick fascia was not built until about 1970. By this time, 2156-yards of the tunnels combined were lined with brick. Come the year 2000, trains using the tunnels were restricted to a speed of 20 MPH. In 1999, a landslide at the site had derailed four carriages of a passing train and soon after, a number of chalk falls within the tunnels were recorded. The latter were partly attributed to the building of the Wainscott Bypass over the chalk ridge; this was completed in the year 2000 and vibrations caused by road traffic were thought to be having an adverse effect on the tunnel lining. Drainage had also been a long-term problem, since the floors of the tunnels are at water level. Consequently, on 18th January 2004, both Higham and Strood Tunnels were closed to rail traffic for exactly one year, to allow strengthening work to take place. This involved re-lining both tunnels completely with concrete, to prevent further chalk falls and to make the bores watertight. The scheme was priced at £35,000,000. Track re-laying began on 1st November 2004 and the tunnels re-opened to regular traffic as scheduled, on 18th January of the following year. The completed works permitted a vastly increased speed limit through the tunnels of 70 MPH.

2nd June 2010

The 13:58 Faversham to St Pancras International service, formed by the customary Class 395 unit, is seen

bursting out of Higham Tunnel: next stop Gravesend. The line through the tunnels is as straight as a die,

and, indeed, on this day, light at the far end of Strood Tunnel can be seen. David Glasspool

2nd June 2010

Class 465 No. 465240 is seen forming the 14:20 Gillingham to London Charing Cross service, as it emerges

from Higham Tunnel. Today, the canal can still be traced at this point; its remnants exist behind the ''down''

platform of the station, as a narrow drainage ditch.  David Glasspool

Tunnel Flooding >>

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