Roman roaming

This presented another problem for the early railway builders: when they tried to get the legs of their tall, slender viaducts to stand up straight, they found that the ground beneath their feet had been, quite literally, undermined.

To overcome these obstacles, they turned for inspiration to a great lost civilisation.

Let’s follow them, and go roamin’ after the Romans.

Wemet Thomas Elliott Harrison in Memories 97: he was the genius engineer who, between 1854 and 1857, designed the line from Bishop Auckland to Durham City. It included three great stone viaducts over the River Wear: the nine arches at Newton Cap; the 11 arches through Durham City, and then nine more arches at Belmont.

But this line was not the first time Sunderland-born Harrison had tackled the deep valley of the Wear. Indeed, one of his first major projects, begun when he was only 26, was to build a Wear viaduct that includes what is still the largest span of a masonry railway bridge in England.

It was for the DurhamJunction Railway. In 1834, it was planned to run southwards from the Stanhope and Tyne Railway in Washington, cross the Wear between Fatfield and Penshaw, and then wander off in to central Durham where the proprietors hoped to link up with one ofthe lines being built northwards from the docks of Hartlepool or Port Clarence.

At first, young Harrison planned to span theWear with a huge iron bridge, but then he consulted the president of the Institution of Civil Engineers, JamesWalker,who suggested a masonry structure based on the Alcantara bridge in Spain.

This is a Roman bridge, built over the River Tagus in about AD100 by order of Emperor Trajan.

However, the Roman Emperor’s men didn’t have the problems to contend with that Harrison had. Around and beneath the Wear at Penshaw were old mine workings.

Harrison had planned to have two identical-sized central spans, but he discovered that the only way he could plant the legs on secure foundations was by increasing one span to 160ft and decreasing the other to 147ft.

Lopsided, work began on March 17, 1836, and the last stone was laid on August 28, 1838 – the day of Queen Victoria’s coronation.

Nowadays, we get two bank holidays when the chap who may one day be heir to the throne gets married; back in 1838, they were hard at work on Coronation day itself.They did, though, mark the royal occasion by naming it Victoria Viaduct.

When it opened in 1839, it was one of the great engineering feats of its day – and it remains so.

“The main span of the viaduct remains the largest for a masonry railway bridge in England – not a bad achievement for the first major structure to be constructed under the supervision of an engineer still in his twenties,” say John Addyman and Bill Fawcett in their biography of Harrison.

Renowned architectural historian Nikolaus Pevsner went further. In the early 1950s, he visited the viaduct, looked up at the Penshaw Monument – built in 1848 as a half-size copy of the temple of Theseum in Athens – and asked: “Is there any other place where one can stand beneath a ‘Roman’ viaduct and see a ‘Greek’ temple nearby?”

The viaduct carried the main line until 1872, when it was diverted through Durham City. The viaduct then carried the “Leamside line”.The 1960s Beeching Axe removed passengers from its trains; it closed to freight in 1991.

There is regular talk of it reopening, but now even the rails of the Leamside line are being lifted. T HOMAS HARRISON, , faced similar foundation difficulties when building the line between Bishop Auckland and Durham City in the 1850s.

The river bed atNewton Cap was so unstable, the footings were sunk 20ft down. To steady Durham’s stupendous viaduct, “piles of great length had to be driven through peatmoss, quicksand etc by steampower,” and uncharted mine workings at Belmont meant the footings had to go down 80ft.

And, reported the Darlington and Stockton Times approvingly on opening day, Mr Harrisonhadused “Romancement” to hold the Belmont viaduct together. Quite probably all of the stones in his other Durham viaducts were stuck to one another by “Roman cement”.

But what, asked Memories 99, is “Roman cement”?

Terence Gilligan, of Darlington, knew, as did Eric Barker, of Sedgefield, Peter Baker, of Gainford, Charles McNab, of Hurworth, Peter Appleton in email-land and Charles Morris, on Teesside, who sent an eight-page essay entitled 160 Years of Cement Manufacturing in Cleveland.

Itwasunputdownable, as an essay on cement-making should be. And it contained plenty of, ahem, concrete details.

For thousands of years,man has known that if you burn l i m e s t o n e in 1,000- d e g r e e temperatures in a kiln and t h e n slake it with water, it will expand and then crumble into a powder – there are tumbledown lime kilns in dales all over the North-East.

If you add this powder to sand and water, you create a gluey mortar.

The Romans discovered a sandwhichcontainedvolcanic ash near the town of Pozzuoli.

When added to the mix, it created a pretty pink mortar that set under water. This magical property of “pozzolana” was because the ash contained silica and alumina.

When away from volcanic places,the Romans ground up bricks,tiles and pottery which contained the same compounds.

But when the Romans left, the Britishforgothowtomake this special cement.

In 1790,the Reverend James Parker of Kent tried to recreate the Romans’ recipe, and started selling “Parker’s Roman Cement” to canalbuilders.

Once people realised what the recipe required,they started looking for thenaturally occuring minerals among their local rocks. As luck would have it, they found them in “cementstone” – a kind of limestone – amid the layers of the North-East coastal cliffs.

In fact, miners were throwing cementstone away as they dug in search of shales containing alum.

Other people then discoveredtons of cementstone lying on the beach where it had fallen out of the cliffs.

In 1811, Lord Normanby started the Mulgrave Cement Works atSandsend,nearWhitby: he had a large kiln for burning the stone, and a watermill for grinding it into powder. In 1817, a steampowered cementworkswas opened atLoftus,further up the coast.

For at least the first half of the 19th Century, the output was sold as “Roman Cement” – the amazing cement that sets under water. It seems likely, then,thatmore than150 years after they were built, Harrison’s great viaducts over the Wear are still held together by Romancementfromthe Cleveland coast.

THE day after reading Memories 99’s Roman cement request, John Ashby was on the train home fromKing’s Cross reading Bill Bryson’s book, At Home. In it, Bryson tells a story about the Reverend Parker’s Roman Cement.

At the start of the 19th Century, wealthy art collector William Beckford appointed architect JamesWyattto build an abbey inWiltshire to house his collection. Wyatt was one of the greatest architects of the day, and one of the greatest drinkers of his day.

He also exhibitedaworrying penchant for destroying things.

For example, at Durham Cathedral, he planned to sweep away theGalilee Chapel and the grave of theVenerable Bede, and he designed a mighty spire to sit on top of the building. Fortunately, his ideas never came to fruition.

At Fonthill Abbey in Wiltshire, though, he put all of his gargantuan ideas into practice, including lofty spires and towers. To hold it all together, he used the Rev Parker’s Roman cement.

“Unfortunately, the reverend’s cement had little inherent strength and, if not mixed exacted correctly,tended to fall apart in chucks – as it did at Fonthill,” says Bryson.

In fact, in the late 1790s, the abbey collapsed twice during construction – and when it was completed, “it creaked and groaned ominously”.

Wyatt by this stage was too drunk to care. Says Bryson: “Beckford bombarded Wyatt with outraged letters. ‘What putrid inn, what stinking tavernorpox riddenbrothelhides your hoary and glutinous limbs?’ ran one typical enquiry.”

Fortunately for County Durham, Thomas Elliot Harrison was made of more sober stuff.