Thursday, 20 October 2016

The Fall of the Tay Bridge - An Unnecessary Disaster: by Ann Swinfen

On the afternoon of Sunday the 28th December 1879 a passenger train belonging to the North British Railway Company set off from Waverley station in Edinburgh, bound for Granton, on the south bank of the Firth of Forth. From there the passengers embarked on a ferry across the estuary to Burntisland, where a second train, known as ‘the Edinburgh’ was waiting to carry them across Fife towards the city of Dundee, situated on the north bank of the River Tay. Here there was no need for a ferry – only a little over a year before, the river had successfully been bridged for rail traffic. A great storm was hurtling down the valley of the Tay. When the train pulled into St Fort station - the last stop before the bridge - the passengers no doubt were looking forward to getting home at last on the other side of the river. But part way across the bridge the ‘high girders’ over the navigation span collapsed into the raging waters below, taking with them the train, its passengers and its crew.  There were no survivors.
The bridge after the collapse

The Tay Bridge Disaster of 1879 is well known to the people of Tayside and Fife. Children in primary schools learn about it; over the years there have been various articles about it in the local press; several books have been written about it; and on the 134th anniversary of the Disaster, on the 28th December 2013, substantial granite memorials were erected to the victims at moving ceremonies on both sides of the TayOne might be forgiven for imagining that the last word had been written on the subject, and that there is no more left to say.

And yet there are two highly important – indeed central – aspects of the story about which there is still a vigorous debate and, as yet, no firm consensus. These are the cause or causes of the collapse, and the true number of the victims lost.

The directors nervously cross the bridge before it opens

At the time of the disaster, the bridge had been standing for barely eighteen months. The longest bridge in the world at the time of its constructions, it was hailed as an engineering triumph. Famous visitors from all over the world came to marvel at its size and splendour, including the Emperor of Brazil, Prince Leopold of the Belgians, and former President of the United States,Ulysses S. Grant. Even Queen Victoria herself ventured out of her self-imposed seclusion to ride across the bridge and attend a civic reception in Dundee. At the grand opening, the Piper of Dundee played and poems in its honour were read.
The opening of the bridge

In the following year, when the bridge fell, how many perished? It has long been accepted that all the passengers and crew without exception were killed, as the train plummeted into the river from a height of nearly 90 feet. What is not so clear is just how many passengers there were on the train at the time. Most commentaries on the disaster in recent years have opted for a figure of around 75, and there is good evidence for this number. For one thing it was the figure accepted by the Court of Inquiry set up immediately after the collapse. The Court in its turn based its conclusion on the evidence of station staff at St Fort station, where, for whatever reason, it was the normal practice for the tickets for passengers travelling to Dundee to be collected. These officials reported that they had collected 56 tickets, to which should be added passengers with season tickets, those travelling beyond Dundee and the members of the crew – a total of between 72 and 75.

Yet there was another source of evidence, arguably more robust. All deaths associated with the bridge were registered with the Parish of St Mary’s in Dundee, and the death certificates ultimately lodged in the National Archives of Scotland in Edinburgh. These certificates number only 59 – exactly the same names and number as were recorded in the police list in the archives of the police in Dundee. Of these 59, 47 were male, and 12 female. In the event, only 46 bodies were ever recovered. Moreover, from time to time the local press published the names of victims, and the latest of these, on 1st January 1880, included only 56 names

In other words, the only incontrovertible evidence for the number of victims supports the conclusion that there were 59, rather than 75. Of course it is still possible that there were more, who in one way or another escaped scrutiny, but it seems highly improbable. The great majority of the known passengers were local – typically travelling back to their work in Dundee after visiting families in Fife. It is a reasonable assumption that the same would have been true of any other passengers not recorded in the list of death certificates. Could it be that some 16 people were also lost without family, friends, or employers ever noticing? While there may have been more than 59 victims, if there were, we do not know their names or how many there were. This is why the Memorials raised to the victims in 2013 firmly state that ’fifty-nine victims, men women and children, are known to have died’ in the catastrophe.
Memorials on the Fife bank of the Tay

Then, what about the other key question – the cause or causes of the collapse?
To understand that we need to know something of the history of the bridge and its construction. The rail bridge over the Tay was the first stage of an ambitious plan on the part of the North British Railway company to out do their great rival, the Caledonian, by replacing passenger ferries across the Forth and Tay rivers with two great bridges, able to carry rail traffic without interruption between Edinburgh and Aberdeen

The Company engaged Thomas Bouch, an experienced railway engineer, to carry this out. Bouch’s original intention was to carry the railway line on a single line bridge supported for almost all of its length on tall brick columns. Unfortunately it became only too clear in the course of construction that the river bed, believed to be solid rock for most of its width, was only partly so – much of it was in fact composed of conglomerate under a thick layer of mud.

This realisation caused a rapid rethink, and Bouch came up with an alternative to support the remainder of the bridge with towers made from cast iron columns bound together with wrought iron tie bars. These tie bars in turn were attached to the columns by nuts and bolts which passed through holes in lugs, cast integral with the columns. It is generally accepted that it was these cast iron lugs which fractured, rendering the towers unstable, and initiating a progressive collapse of the structure, taking with it the train.
Joints with Lugs
It is here that the consensus breaks down. Broadly there are two schools of thought about the causes of the collapse – either the train brought down the bridge, or the bridge brought down the train.

In the first of these two camps we find Bouch himself. He was firmly of the opinion that what had brought down the train was the accident of a second class carriage coming off the rails, catching on one of the side girders, and ripping the whole structure apart. Some colour was given to this explanation by the fact that there was a known distortion at one point in the rails, caused it has been claimed by an accident in the course of construction when two of the ‘high girders’ were blown off their supports into the river. One of these was repaired and reused, leading to a ‘kink in the rail’ which could have unsettled a carriage as it passed over it. Bouch pointed to certain scrape marks on one of the side girders, which could have been made by contact with a carriage.
Girder No.4
Against that there was the fact that the marks were too high up to be reached by a toppling carriage. Dugald Drummond, chief engineer for the North British, for his part was convinced from the state of the rolling stock, that all its components had remained on the track as it fell.

A recent and intriguing contribution to the debate has been the claim that the lugs failed due to metal fatigue, induced by the passage of trains over the bridge since its inception. But this explanation has not found favour with experts in the field, who have concluded that the operational life of the bridge was far too short for metal fatigue to have set in.

So what are we left with? If the bridge itself was the cause of the demise of the train, how did that come about?

Here we need to return to the conclusions of the Court of Inquiry, which amongst other things focused on the design of the bridge, with particular reference to the question of wind pressure, and the design of the lugs, crucial to the failure of the whole construction. Bouch came in for particular criticism for his failure to make sufficient allowance for the pressure of wind against the fabric of the bridge, although it was clear that even officials at the Board of Trade, including the Inspector of the bridge, Major General Hutchinson, were not accustomed to make any such allowance for lattice girders of the length and type involved. Nevertheless it is the firm opinion of modern experts that one of the key causes of the collapse was the extreme pressure of wind on the fateful night.

The second major factor was the design and method of manufacture of the lugs to which the tie bars had been bolted. The most obvious problem was that, in the process of casting, the holes in the lugs, which were to take the connecting bolts, ended up being conical in shape instead of truly cylindrical. This had the effect of concentrating all the stress of the connection on a narrow ring of metal. On top of that, as a cost cutting measure, Bouch had specified bolts which were one eighth of an inch smaller that they should have been. 
Belah Viaduct

Again, if only Bouch had chosen to use the kind of wrought iron ring clamps he had used on the Belah Viaduct in the North of England, instead of the fragile lugs, the disaster might well never have happened at all. Why didn’t he? Because they were too expensive.
Belah Wrought Iron Clamps
Various other contributory factors have been cited as explanations of the fall. The great height of the bridge above the high water level, which arguably made it less stable, was due to fears of the authorities in Perth, up river from the bridge, that their seaward trade might be affected. That it was a narrow single line bridge at all was down to the directors of the North British – again a matter of cost. That Henry Noble, charged with the maintenance of the bridge after it came into operation, had tried to cure ‘chattering’ in the bridge components as economically as possible by hammering wedges of iron into them, may well have forced the bridge out of true.

But in the end one comes down to the simple facts.  The bridge collapsed in a fierce and unremitting gale for two fundamental reasons – the lack of a sufficient allowance for wind pressure in the design, and the fatal decision to rely on the cast iron lugs to hold the towers together, instead of the Belah clamps. Not surprisingly, Bouch, as the designer of the bridge, was devastated by the collapse of the bridge, the tragic loss of life, and the ruin of his professional reputation. He survived the fall of the bridge by less than a year.

The Tay Bridge Disaster was an engineering catastrophe, but above all it was a human tragedy. Most of the victims were young, 10 of them 18 or under, the youngest only 5. But consider the remarkable escape of six year old William Brown. William lived in Dundee with his widowed mother, one brother and two sisters. In late December, 1879, he was looking forward to travelling to Leuchars in Fife with his grandmother and his elder sister to visit his uncle Charles. But he had been very naughty – the exact nature of his crime is not revealed – he was given a severe beating by his mother, and forbidden to go on the visit. That was the last he saw of sister Elisabeth and their grandmother.
Memorials on the Dundee bank of the Tay. The new bridge in the background.

Published 20 October 2016, the new and updated edition The Fall of the Tay Bridge, by David Swinfen:

Ann Swinfen


Sue Purkiss said...

Wasn't there a novel by A J Cronin in which the disaster featured very prominently? It's a very long time since I read it, but it made a powerful impression.

Susan Price said...

Well done for not mentioning McGonagle!
Fascinating post: thank you.
Knowledge of the disaster always lends a certain frisson to crossing the modern Forth and Tay bridges, despite all the years they've stood.

Janie Hampton said...

Fascinating piece of clear detective work. thank you!

Catherine Hokin said...

Really interesting, thank you. I recently made my American husband read the McGonagall poem - he was in recovery for quite a while after that!