Tay Bridge Disaster Letters 3: ‘The Tay Bridge of the Past and Future’ (31 January, 1880)

On the 28 December 1879, the Tay Rail Bridge designed by Thomas Bouch collapsed in a terrible storm. The disaster claimed the lives of all 75 passengers (although only 60 bodies were found). Naturally the tragedy featured heavily in ‘The People’s Journal’ and large features on the inquests were regularly found in the paper throughout 1880. Amongst the reporting there were also letters from readers published about the events. In this letter William Leslie from Alyth dismisses some of the previous letters to the paper about the bridge’s faults. There is also a note from a correspondent from Derbyshire who decries the cheapness of the materials used.

 

Sir,—I have read with much interest all the various letters on the above subject which have lately appeared in your paper, some of these written by more indignant than experienced persons. One correspondent writes—”No doubt the weakness of the Bridge was its length.” There, I may say, he is decidedly under a mistake, for the Bridge was designed so as to be equally strong between any two of the highest pillars as between the first pillar and the land, and if these pillars were to blame the error lay in the calculation of their strength and not in the length of the Bridge. Another says that, “seeing the iron pillars were tubular and filled with cement, perhaps water had got into them, and when the frosty weather came the water expanded and the iron contracted, so damaging the pillars.” This is right so far, although no water could have got into these pillars. Nevertheless, seeing firmed cement has no yield, the contraction of these pillars should have been provided against. This could easily have been done by putting between the cement and the pillars oneply of ordinary pipe bagging. Another condemns the Bridge at once as “a wind trap,” and tries to make out that the lattice girders strain the supporting piers greater than the plates. In support of his theory he says—”Had the side of the Bridge presented a solid body to the wind the current would have divided before it reached the Bridge, and passed above and underneath it.” Now, if this was the case, bridges built on the solid or plated design (such as tubular bridges) would require no extra support to provide against oscillation, and would be recommended above all others. But such is not the case. Although the Bridge had presented a solid body to the wind, and divided the current into two parts, the space between the currents was not a vacuum, but compressed air equal in strength to the passing currents, and the stronger these currents grew the lesser grew this space, and the greater the pressure against the side of the Bridge. The lattice girder prevented this pressure, was equal to any other pattern in strength, superior in beauty, and I believe inferior in price. Yet, for one fault, I would condemn the bare lattice girder, that fault being the want of protection to the passing train from the wind. I believe this will be one of the most difficult points to settle in the reconstruction of the Bridge. Although no carriage was ever proved to be overturned by the wind, yet it would be well to provide against it, seeing the wind once before blew one of these girders—far heavier than any carriage—from the top of the Bridge into the river. As to the question of rebuilt, continuing the levels where the Bridge is broken. This would only lower the shipping height some twelve or fifteen feet, to which the town of Perth could not reasonably object, as it would not lessen their shipping interest nor diminish their traffic. Yet it would not be commendable to allow the North British Railway Company to run passenger trains across the Bridge until another line of rails was added, b a new Bridge built alongside the present one and firmly connected with it, both having supports slanting out into the river as far as the fallen engine lies from the base of the upright piers, thus forming a bridge that would meet the demands of the public, and on which the most timid passengers could safely venture.—I am &c.,

Cumno, Alyth. Wm. Leslie.

A correspondent, writing from Derbyshire, says:—I have moved a good deal among English iron-workers in the Midlands. There seems to be a decided opinion among many that there was too much cast-iron in the structure, and that not of the best quality either. This class of iron cannot bear a sudden strain like good wrought iron, and doubtless the large quantity of cast, especially in the under structure, if not the upper, was a factor in the downfall of the Tay Bridge. One bridge here of the Midland Company’s across a valley, a double line, quarter of a mile long, I am told and have seen, has a much larger proportion of wrought iron in its structure, and the girder work is much closer, and therefore much safer. The cheapness of the Bridge is also a free subject of comment. I hope the next will be a double line, with less cheap cast-iron in it, and wrought iron of the best wherever lateral pressure is expected. Also, let it be lower, and less ado made about it when finished until the first or second hurricane is past. It brings a dear bought experience to my native town, which I visited lately, and crossed the Bridge the day before it fell. Got help the sufferers.

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