Sir Thomas Bouch's Tay Bridge and the Tay Bridge Disaster

The first excerpt here is from "The Tay Bridge: Part I" in the 1878 volume of the periodical Good Words. The author, the civil engineer Albert Grothe (1841-1914), was the Manager of the original Tay Bridge Project. Grothe was immensely proud of the bridge, designed by Sir Thomas Bouch (1822-1880), and, at that time, "the longest bridge in the world" (Grothe I: 43). The next excerpt is from "Tay Bridge," the Address to the Board of Trade by the Chief Inspector of Railways, Colonel William Yolland (1810-1885), and the civil engineer William Henry Barlow (1812-1902), which forms the forward to the HMSO report of 1880 on the Tay Bridge Disaster for the Court of Enquiry. The last excerpt is from the report itself, prepared by Henry Cadogan Rothery (1817-1888), Commissioner of Wrecks. Publication and archive details are given in the bibliography below. The excerpts have been selected, formatted and illustrated for the Victorian Web by Jacqueline Banerjee, who also added the postscript. Omissions are marked by ellipses and page numbers at the turn of the page are indicated in square brackets. Click on the images to enlarge them.

I: Albert Grothe's Description of the First Tay Bridge

"The Tay Bridge from the South Side" (Grothe I, facing p. 104).

At the site of the bridge the Firth of Tay is about two miles broad. On the south side trap rocks rise abruptly to a height of about fifty feet out of water; on the Dundee side they have a more gentle slope. In both cases they very soon disappear towards the centre of the river, and are only found at depths which put it out of the question to use them as a foundation for the various piers. Their place on the river bottom is partly taken by clay and boulders, partly by sand; and under the latter, in depths of about eighteen feet, a stratum of gravel is found, which is quite capable of sustaining the weight which is to be put upon it. There are in all eighty-five piers supporting spans of varying lengths, and differing according to the weight of the latter. Those piers which stand on the solid rock are entirely constructed of brickwork set in Portland cement, a substance which in its ordinary state is a fine greenish-grey powder, but when mixed with water it becomes hard in the course of a few minutes, and after two or three days attains a degree of strength which ordinary lime mortar would not have for years.... It largely enters into the construction of the lower parts of all the piers, and has the advantage of being easily worked by not particularly skilled workmen. Without this, or some substance of similar properties, the building of the Tay Bridge would in all probability have been impossible.

"Floating out" (Grothe I: 41). Grothe writes, "The piers and girders were to be erected on shore, and floated out to their destination. The consistency with which this principle was carried out would distinguish this bridge from all other structures of the same kind, even if its size and importance were less remarkable" (Grothe I: 43).

The piers which are not founded upon rock require, of course, an extended base to carry the great weight with safety. The former consist of two cylinders of nine feet six inches diameter, while those standing on gravel, and supporting spans of the same length, have the diameter of these two cylin- ders enlarged to fifteen feet, and their top weight is greatly reduced by substituting for the heavy brickwork above high water, cast- iron columns, fixed together by horizontal and diagonal transverse bracing.

Thirteen of the spans over that part of the river which is generally used for navigation are two hundred and forty-five feet long, and the piers are so high that at the highest water there are eighty-eight feet of clear waterway left — more than sufficient for the class of vessels plying from Dundee to places above bridge. The girders composing these spans are placed so wide apart that the trains can pass between them, the roadway being fixed at the bottom of the girders. In the other parts of the river this great height is not required, and the piers have therefore been kept much lower, the iop of the spans in this part being level with the bottom of the large ones, and the rails being laid on cross sleepers resting on top of the girders. In this manner the roadway forms an un- broken line, while there seems to be a step in the girders — a circumstance which puzzles many, till a walk on the structure has shown them that the engines will not by any means have to perform the wonderful acrobatic feats which a view from a distance would lead one to expect. [Grothe I: 42/43]

On the Dundee side the line has to pass the town underground.... The length of the spans on this part varies from one hundred and sixty-two feet to sixty- nine feet, and quite near the shore a large span of one hundred and seventy feet is constructed, with a view of offering facilities for a future extension of the esplanade, which would necessitate the construction of a roadway under this span. For the same purpose it is built on the "bow-and-string" principle, and the rails kept at the bottom. Parallel girders, like those of the large spans, might of course have been used; but what is no disfigurement when carried out over a great length would look very bad indeed if applied to a single span. Now the curved top-boom makes the transition an easy one. The last six spans on the Dundee side, so far as they belong to the Tay Bridge contract, are short ones, being only twenty-seven feet long. Three more of these, and a " bowstring" of one hundred feet, complete the iron part of the bridge, bringing the total length to ten thousand six hundred and twelve feet, or two miles and fifty feet.

On the south side the same reasons for constructing a strong incline did not exist. As the land at the south shore is about seventy feet above high water, an easy slope of one foot in three hundred and sixty^five was sufficient to bring the line to the re- quired level. The spans on that side are mostly of one hundred and forty-five feet and one hundred and thirty feet in length. There are only two of eighty-eight feet and three of sixty-seven feet near the shore.

To complete the general description of the bridge, it will only be necessary to mention that, in order to join the land portions of the line, a long curve had to be introduced on the north side extending over nearly a quarter of a circle, and one of less length on the south side, giving the bridge in plan the appearance of a gigantic S. From the shore the curves, especially the one on the Dundee side, appear to be very sharp, but in reality they are not, both having a radius of twenty chains, while on other lines curves of eight chains are frequently met with (Grothe I: 42-43).

II: Excerpts from the Address to the Board of Trade by Colonel William Yolland and William Henry Barlow

1. The completion of Sir Thomas Bouch's Tay Bridge:

The bridge was inspected by General Hutchinson on the 25th, 26th, and 27th February 1878, at which time it was all finished and painted. During this inspection he subjected the bridge to various tests, and among others he caused six locomotives coupled together, each weighing 73 tons, to pass over the bridge at a speed of 40 miles per hour. The behaviour of the bridge under these tests appears to have been satisfactory, there having been only a moderate deflection in the girders, a small degree of tremor, and no indication of looseness in the cross bracing.

On the 5th of March he reported that he saw "no reason why the Board of Trade should object" to the bridge being used for passenger traffic; but that it would "not be desirable that trains should run over the bridge at a high rate of speed," and suggested "25 miles an hour as a limit, which should not be exceeded," adding that "very careful attention will be required to ascertain from time to time that no scouring action is taking place in the foundations," and that he should wish, if possible, to have an opportunity of "observing the effects of a high wind when a train of carriages is running over the bridge." Some delay occurred in opening the [8/9] bridge owing to the approaches on either side not being completed, but on the first day of June 1878 it was open for passenger traffic, and from that time trains continued to run regularly across it until the evening of the 28th of December last, when the disaster which we are now about to describe occurred. (Yolland and Barlow 8-9)

2. The circumstances of the disaster:

"The Tay Bridge Disaster — Visit of the Official Steamer to the ruins on the night of the accident." The Graphic, 3 January 1880.

The train previous to that which fell with the bridge left Tayport about 5.50 p.m., and passed over the bridge about 6.5 p.m. The engine-driver did not notice anything unusual in the travelling of this train, but the guard, Shand, and two men who were with him, saw sparks of fire coming from the wheels of the carriages.

Shand put on his break and showed his red light, but it was not seen by the driver; he also examined his train at the Dundee Station, but finding nothing wrong made no report.

The train from Edinburgh which fell with the bridge arrived in due course at St. Fort Station, and there the tickets of the passengers for Dundee were as usual collected. We were told by the ticket collectors that there were at that time in the train 57 passengers for Dundee, five or six for Broughty Ferry, five for Newport, two season ticket holders, the engine driver, stoker, and guard of the train, and two other guards, making 74 or 75 persons altogether. The tickets having been collected, the train proceeded on its course, leaving St. Fort Station at 7.8 p.m., and on approaching the cabin which stands at the southern end of the bridge, the speed was slackened to about three or four miles an hour to enable the engine driver to take the baton or train staff, without which he is not allowed to cross the bridge. On receiving the baton, steam was again turned on, and the train passed on to the bridge, upon which the signalman, Thomas Barclay, signalled to the north cabin signalman, the time according to the entry in his book, being exactly 13 minutes after 7 o'clock.

It was then blowing a strong gale from about W.S.W., and therefore almost directly across the bridge ; there was a full moon, but it was quite dark, owing to the face of the moon being obscured by clouds. It seems that a surface man in the employment of the North British Railway Company, named John Watt, had gone to keep Barclay company, and was in the cabin when the train passed; and whilst Barclay was attending to his duties, entering the time in his book and making up the stove fire,

Watt was watching the train through the window in the cabin door, which looks north along the line. According to Watt, when the train had got about 200 yards from the cabin, he observed sparks flying from the wheels ; and after they had continued about three minutes, there was a sudden bright flash of light, and in an instant there was total darkness, the tail lamps of the train, the sparks, and flash of light, all, he said disappearing at the same instant.

The portion of the bridge which fell consisted of three sets of continuous girders, covering respectively five spans, four spans, and four spans, making thirteen spans altogether.

These continuous girders rested on rollers on all their piers except one near the centre of each set, and to these central piers they were fixed. In the accident which took place, the girders turned over and fell on their sides, each girder becoming slightly curved, the centre portion being furthest from the piers, and the ends curving towards the piers, some irregularity showing itself in the curve at the first fallen pier from the south end.

The train was found partly in the fourth and partly in the fifth spans from the south end, so that, although it had travelled some distance along the first set of continuous girders, it never reached its northern extremity. The engine and tender were found lying on their sides on the eastern girders. The train consisted (counting from the engine) of one third class, one first class, two third class, one second class, and the guard's van. The second class carriage and the guard's van had their bodies and all their upper portions entirely destroyed; their lower frames were greatly damaged, and the axles of these vehicles as well as those of all the other carriages were bent.

The throttle valve of the engine was full open, and the reversing lever standing in the sixth notch from full forward gear, or in the third notch from the centre.

The train was partly fitted with the Westinghouse break, but there was no appearance of its having been put on, and the conclusion to be drawn from these facts is that neither the driver or fireman had any warning of the accident which took place (Yolland and Barlow 9).

III. Excerpts from Rotheby's HMSO Report

1. The true cause of the disaster:

.... With its conical bolt holes in the lugs and in the flanges of the 18-inch columns; — with its lugs, shown by experiment to be unable to bear more than one-third of the pressure due to their sectional areas; — with the wind ties, by which the columns were held in position, loose ; — with no effective supervision of these cast-iron columns and their attachments to see that they were doing their work properly ; — with all these and the other defects, [Rothery 40-41] to which we have called attention, can there be any doubt that, what caused the overthrow of the bridge, was the pressure of the wind, acting upon a structure badly built, and badly maintained.

What probably occurred was this. The bridge had probably been strained partly by previous gales, partly by the great speed at which trains going north were permitted to run through the high girders. The result would be that, owing to the defects, to which we have called attention, the wind ties would be loosened; so that, when the gale of the 28th of December came on, a racking motion would be set up between the two triangular groups, into which the six columns forming each pier were divided. This would bring a great additional strain upon the wind ties between the 15-inch columns which connected the two groups of columns together, and which would receive comparatively little support from the ties between the outer 18-inch and the two nearest inner columns, owing to the angle which they made with the line of pressure. The strain, too, upon the lugs being greater, as you descended the columns, the places, at which the columns would naturally give way, would be near their bases; unless, indeed, a weaker spot should display itself higher up, as appears to have been the case in piers 29 and 30, where the two lowest and the lowest tiers respectively are still standing. Whether, indeed, the lugs or the bolts went first, it is impossible to say; but as soon as one went, an additional strain would be brought upon the other, and the columns being thus without support, would naturally fall over to leeward, as some of the witnesses described it, like a pair of rulers (Rothery 41).

2. Rothery's apportioning of final responsibility:

The conclusion then, to which we have come, is that this bridge was badly designed, badly constructed, and badly maintained, and that its downfall was due to inherent defects in the structure, which must sooner or later have brought it down. For these defects both in the design, the construction, and the maintenance, Sir Thomas Bouch is, in our opinion, mainly to blame. For the faults of design he is entirely responsible. For those of construction he is principally to blame in not having exercised that supervision over the work, which would have enabled him to detect and apply a remedy to them. And for the faults of maintenance he is also principally, if not entirely, to blame in having neglected to maintain such an inspection over the structure, as its character imperatively demanded (Rothery 44).

3. Rothery's conclusion:

It seemed to me ... that we ought not to shrink from the duty, however painful it might be, of saying with whom the responsibility for this casualty rests. My colleagues thought that this was not one of the questions that had been referred to us, and that our duty was simply to report the causes of, and the circumstances attending, the casualty. But I do not so read our instructions. I apprehend that, if we think that blame attaches to any one for this casualty, it is our duty to say so, and to say to whom it applies. I do not understand my colleagues to differ from me in thinking that the chief blame for this casualty rests with Sir Thomas Bouch, but they consider that it is not for us to say so (Rothery 48).

Postscript

There would be continued speculation about the cause of the disaster, but the HMSO report's conclusions still seem sound. Mathematician and authority on the Tay Bridge, Tom Martin writes at the end of his comprehensive web pages on the collapse:

The train could have been derailed before the piers collapsed, there was evidence of bad construction and poor maintenance and there could have been a contribution from fatigue. But these features are not necessary to explain the collapse. The bridge was doomed due to bad design. If the wind on 28th December 1879 had not caused the collapse a later stronger wind would have done the job. ["Conclusion"]

Martin supports this conclusion convincingly in full technical detail in a paper co-authored with another expert, Professor Ian MacLeod, entitled "The Tay Bridge Disaster Revisited" and published in the Proceedings of the Institution of Civil Engineers in December 2004. The abstract of this paper reads: "A view is being expressed that the Tay Rail Bridge disaster of 1879 was not fundamentally due to the action of the wind but was a result of fatigue damage caused by dynamic loading. The paper discusses this proposition and shows that the evidence to support it is weak" (187). Absolute certainty about its immediate cause may not be possible, but the tragedy still resonates in the popular imagination today, and remains one of the greatest ones ever to have befallen a bridge-engineering project. — JB

Note: Tom Martin writes to say that since this account was compiled, he has developed a new website (see updated bibliography below) with five video clips from the Open University podcast in which he participated. Some key papers and articles on the subject, including several by Robert Shiels examining the disaster from a legal viewpoint, can be downloaded from the website.

Related Material

Bibliography

Grothe, Albert. "The Tay Bridge: Part I" and "The Tay Bridge: Part II." Good Words (1878). 40-44; 103-06. Internet Archive. Contributed by the Prelinger Library, San Francisco. Web. 21 March 2016.

Lumley, Robin. The Tay Bridge Disaster: The People's Story. Stroud: The History Press, 2013.

Martin, Tom. "Conclusion." Tom Martin's Tay Bridge Disaster Web pages (https://taybridgedisaster.com). Web. 21 September 2024.

Martin, T. J. & I. A. MacLeod. "The Tay Rail Bridge Disaster Revisited." Proceedings of the Institution of Civil Engineers. December 2004, issue BE4: 187-192.

"Obituary. Albert Grothe, 1841-1914." Minutes of the Proceedings of the Institution of Civil Engineers. ICE Virtual Library. Vol. 198, issue 1914, Part 4. Web. 21 March 2016.

Rothery, Henry Cadogan. Tay Bridge Disaster (HMSO report for the Court of Enquiry). London: Eyre and Spottiswode, 1880. Internet Archive. Contributed by the University of Southampton. Web. 21 March 2016.

"The Tay Bridge Disaster — Visit of the Official Steamer to the ruins on the night of the accident." The Graphic. 3 January 1880. Issue 527. 19c. British Newspapers (Gale).

"Thomas Bouch." Grace's Guide to British Industrial History. Web. 21 March 2016.

"William Henry Barlow." Grace's Guide to British Industrial History. Web. 21 March 2016.

"William Yolland." Grace's Guide to British Industrial History. Web. 21 March 2016.

Yolland, W. and W. H. Barlow. "Tay Bridge." In Rothery. 5-16.

Created 21 March 2016

Last modified 21 September 2024.