The Iron Trunk – a 200th anniversary

One of the more interesting reads in the blogosphere is Narrow Boat Albert, maintained by Steve and Maggie Parkin. They regularly post about their journeys along our waterways, and because they are based at Yardley Gobion, often touch on subjects of Wolverton interest. I have not met the Parkins but the blog posts are always well written and accompanied by excellent photographs.

Two years ago they posted about the lock flight crossing the River Ouse between Wolverton and Cosgrove that preceded the aqueduct here. Again this month they explored the area and discovered the original cutting for the canal. New Year’s walk.

This month marks the 200th anniversary of the Iron Trunk. This is an astonishing record and a testament to early 19th century engineering. The progress to this was not easy, as I described in my December post on the Grand Junction Canal coming to Wolverton.

There were three stages to the Ouse crossing – firstly the lock system from 1792-1799, then the ill-fated wooden aqueduct that lasted until 1808, and the final solution, which is what you see today, 200 years after it was constructed.

Since I posted in December I have learned that Thomas Harrison was involved in another canal project. In 1784 he formed, along with other investors, The Flint Canal Company. The intention was to build a canal from Greenfield to Flint. The canal was never built, but they did build a new stone bridge over the river and a brass plaque, dated September 10th 1788, marks the laying of the foundation stone. This is of some interest to us because it shows that Thomas Harrison was involved in canal projects in an earlier decade and his building of the aqueduct was not a one-off project – although it was certainly his last in this field of endeavour.

The Grand Junction Canal

The late 18th century witnessed a spate of canal building across the country and the creation of these waterways was an important first step in England’s industrial revolution. In 1790 some promoters planned a canal that would join the Oxford Canal at Braunston with the River Thames at Brentford. It was to be called the Grand Junction Canal – a name it bore until quite recently when it was changed to the Grand Union Canal. The proposed new canal would cut through the northern part of the Wolverton Estate and the Radcliffe Trustees met on 14th June 1792 to consider the imploications and came to a quick conclusion in support of the plan. It was the most momentous change to the landscape since the enclosures of the 16th century.

They would not have considered the impact on the countryside since that was a concept unknown to 18th century people, but they did see the advantages of a canal to transport goods. The bisection of farms was a matter easily dealt with by the building of bridges. The canal was approved by Act of Parliament on 30th April 1793.

Work began at both ends of the canal immediately but it was to be some years before the “navigators” came to the middle section in Wolverton. The greatest challenge at Wolverton was the passage across the River Ouse. The original plan provided for four locks on the Southern bank and five locks on the Northern bank but in 1799 the engineer had second thoughts and proposed an aqueduct instead. However, because this project would add a further year of building they went ahead with temporary locks anyway. You can still find the remnants of these on the river bank.

This 1804 map of Old Wolverton shows the lock channel as it once was.

With these in place the canal opened for traffic in the autumn of 1800. Work started on the aqueduct two years later. The contractor, interestingly enough, was Thomas Harrison, the land agent for the Radcliffe Trust and resident of Wolverton House. It is doubtful that he had previous experience of engineering works on this scale but the Canal Company did award him the contract. The aqueduct was built with three arches to support a wooden trunk which was lined with clay to prevent leaks – which it did not. Boats began to use it in August 1805 but it seemed to be a perilous structure from the start. A few months later part of the embankment slipped. Repairs were effected but the Company Architect was not satisfied. Arguments about who was at fault went back and forth between Harrison and the Canal Company until February 1808 when the aqueduct spectacularly crashed overnight.

Thomas Harrison still insisted that he was blameless and the fault lay with the men who had built the aqueduct. The Canal Company sued and took matters into their own hands. They built a temporary wooden trunk in April 1808 so that traffic could resume and commissioned a permanent structure. Stone piers were built and an iron trunk was ordered from the Ketley Iron Works in Shropshire to span the piers. This time they got it right, and in January 1811, the “Iron Trunk” was opened. Next month it will have been in continuous service for 200 years.

Harrison was taken to court and found liable despite his protests and damages were set at £9,262 – a considerable sum of money in those days, but one, which Harrison was readily able to pay.

The aqueduct was not without its consequences. The Ouse was always liable to flooding but in 1823 there was a great flood which even reached Wolverton House to a level of 17 inches above the floor. A civil engineer brought in some years later concluded that the aqueduct was partly to blame because it restricted the flow of water through the piers at high spate. It was not the only reason; the mill race was also a cause.

Before the railways the canal operators more than recovered their investment, but they continued to be of importance in the commercial transport of goods. When I was a boy narrowboats, usually in pairs were still a regular feature, often carrying coal, but by 1960 commercial traffic was gone and leisure craft were increasingly using the waterways.

There were quite important wharves at Old Stratford, by The Galleon at Wolverton and by the New Inn at New Bradwell. Gradually these ceased to function. The presence of the canal and its links to the sea made it possible for the enterprising Edward Hayes to establish his bat building business at Stony Stratford. See this post on Edward Hayes.

In some ways the construction of the canal prepared Wolverton folk for the greater changes which were to come 40 years later with the railway line, and it was in part due to the presence of the canal that the London and Birmingham Railway Company decided to build their engine repair shop at Wolverton.