THERE are those who decry the Forth Road Bridge as a failure of Scottish engineering and construction because it only lasted for 53 years of its expected 120-year lifespan. They point to the Queen, who officially opened the road bridge in 1964 and its successor the Queensferry Crossing earlier this month as being a much longer survivor.

That is so dreadfully unfair to a marvel of Scotland’s modern industries, not least because nothing is longer lasting than Her Majesty.

When it was first planned, the “experts” said that around five million cars, lorries, buses, and motor cycles would cross the bridge every year and they were very hesitant in saying that one day far in the future, that figure might have to increase to around eight million.

Within 15 years of its coming into existence, it was clear that the experts were very badly wrong and the bridge was carrying up to ten million vehicles per year. Another factor that the detractors usually fail to take account of was that the weight of vehicles vastly increased – the maximum weight for lorries in 1964 was 24 tonnes and that increased to 44 tonnes, and there were many more HGVs than anyone ever thought would cross the Forth.

And who ever foresaw the rise of white van man and his goods-laden vehicle? So it is no wonder that the bridge deteriorated much quicker than planned.

In its last full year of operation, about 25 million vehicles crossed the bridge, nearly 10 times the number it carried in its first full year of operations. That is surely not a bad record at all.

It seems almost remarkable now that for decades until 1964 the connection between North and South Queensferry relied on a roll-on roll-off area for which the queues never ceased to lengthen.

Practically since Sir William Arrol’s magnificent rail bridge had opened, there had been talk of a similar crossing for road vehicles but one major problem existed – the rail bridge had taken the best route across the Forth.

By the 1920s, the number of cars on Britain’s frankly poor roads was rising annually. By the early 1930s, when various Road Traffic Acts brought in improvements such as driving tests and compulsory insurance – no wonder, as more than 7,000 people were killed or injured in a single year – meant that proper statistics of road usage could be collated. It was found that 2.5 million vehicles were abroad on Britain’s roads – a much higher number than officialdom perceived.

As early as 1923, the Ministry of Transport had considered the idea of a rail bridge across the Forth to link Edinburgh and the Lothians to Fife and the growing road network in the north and east of Scotland. The ‘missing link’ from Perth to the Forth was designated the A90 instead of the A9 as originally conceived, largely because there was no road link across the Firth.

Though the number of vehicles continued to increase slowly during the Great Depression, that era of austerity followed by the Second World War effectively put all road bridge plans on the back burner, and it was not until 1947 that the Forth road crossing plans resurfaced. Clement Atlee’s government in London started the ball rolling by setting up the Forth Road Bridge Joint Board with the councils around the Forth all involved.

The ferry service continued to expand, and by the 1950s there were four ferries operating round the clock carrying 1.5 million vehicles per year. In 1955, the Joint Board proposed a tunnel under the Firth near the Rail Bridge, but the so-called Maunsell Scheme was abandoned and the Board instead opted for a suspension Road Bridge one mile upstream from the original Forth Bridge, with the towers erected above the sunken Mackintosh Rock on the north side and a rock shelf on the south side.

The project was approved in 1958 with money raised by the various authorities and a contribution from HM Government. The original cost ran over budget and it was eventually built at a cost of £11.5 million with a further £8 million on connecting roads. It was planned that the loans to fund the construction would be recovered from tolls.

The foundations began to be laid in September, 1958, and once again the famous Scottish name of Sir William Arrol & Co was involved. Together with the Cleveland Bridge and Engineering Co, and Dorman Long Ltd, Arrol & Co formed the consortium of the three largest engineering firms in the UK that actually built the bridge which was designed by the two firms of Mott, Hay and Anderson, and Freeman Fox and Partners – all of them British, all using British materials, a point to which I will return.

The construction of what was then the world’s fourth longest bridge span was a long and difficult process, and often dangerous – eleven men lost their lives during the building work, four of those on the bridge itself.

The single worst accident of the whole project was on June 22, 1962, when the Masterton viaduct that was to carry a section of one of the approach roads collapsed and trapped four men, three of them being killed.

Still the work rolled on. Some 210,000 tonnes of concrete were poured into the foundations and bridge surface while the steel cables and other steel elements totalled nearly 40,000 tonnes.

By the end of 1962 more than 30,000 miles or steel cable were in place and the following year, just before Christmas, the last box girder was swung into place to complete the crossing. It bore a Lion Rampant and a Union Flag.

Two engineers who worked on the Bridge told the BBC in 2014 that they, and not foreman Jimmy Lafferty, who was officially the first to cross the bridge, had made it across before the walkways were finished.

Hector Woodhouse, then an assistant engineer on the bridge, said: “They had not quite finished the mesh but we were not going to be stopped.”

His friend Alan MacDonald, a section engineer, added: “We did a tightrope act down the cables so that we could become the first people to cross the bridge.”

The pair stepped off together so that both now claim to be first across the Forth by road bridge.

There then came the task of surfacing the carriageways across the bridge. Incredibly the top layer across the whole surface had to be applied by hand.

There is a documentary that was made to archive the whole building process. You can view it on Youtube, and if you can ignore the deathly commentary, it’s actually a very good overview of the considerable engineering skills that went into the construction.

At its finish, as the official history states, “it was the first bridge of its kind in the UK, the longest outside the USA, and the fourth longest in the world. ‘Guid Passage’ was the fitting motto given the Forth Road Bridge at its opening.”

At 3,300 ft, the central span itself between the two towers was a thing of wonder and awe on the part of the hundreds of thousands who flocked to see it in the months before the bridge’s official opening by Queen Elizabeth.

The opening ceremony itself was very nearly a disaster, for on the morning of September 4, 1964, the haar - the sea mist that often bedevils the east coast of Scotland and is known as a ‘fret’ in England - smothered much of the Firth of Forth.

Television news was then in its infancy and it was up to the newsreels, the radio and the newspapers to bring an expectant Scotland up to date with what had been happening. The haar seemed to deepen but just before noon the sun miraculously broke through and the mist dissipated just enough for the huge crowds of spectators at either end of the bridge to see what was going on. Among them were the 400 workmen who had built the bridge.

Her Majesty’s Royal Cavalcade slowly crossed the bridge and soldiers from Lowland and Highland Regiments linked up to demonstrate the link between the north and south of Scotland.

A flypast by the RAF took place while down in the Forth itself, some 25 warships fired a salute only for the haar to return around them so that HMS Lowestoft crashed into the Home Fleet’s flagship HMS Lion, fortunately with no casualties.

The initial toll charge of a half crown was never going to be enough to repay the various loans that built the Bridge, though such was the volume of traffic in later years that the Forth Road Bridge was said to have paid for itself.

The bridge’s travails in later years have been well documented, including the corrosion of the steel cables that eventually forced the decision to built the Queensferry Crossing, as was the fact that it was declared a Listed Building in 2001.

I will leave the last word to that perspicacious Fifer, Ian Jack, writing in The Guardian the other day: “The new bridge has a tiny British input: a few box girders from Cleveland Bridge, a safety monitoring system from the Arup Group, and 16% of the building work by Morrison Construction.

“The main designers are American, Danish, Dutch, Swedish and German. The main contractors are American, German and Spanish. The steel comes from China, the concrete from Germany, and the cable stays from Switzerland.

“In 1964, a person of a certain age could look back on half a century of terrible events. Looking back at 1964 today, a person of the same certain age can only marvel that Britain was then still an industrial nation, and that its decline has been so recent and so steep.”

The new road bridge over the Forth is both a very international and highly Scottish achievement, and proof, if any were needed, that Scotland can not only survive on our own in the world, but thrive.

Next week we’ll profile the third and final wonder of our brief series on Scottish engineering and construction – Q4. And if you need to know what that codename meant, you will have to buy The National next Tuesday.