Before They Were Famous #2333 – The Tay Bridge


The bridge that collapsed in 1879 was begun in 1871 as the longest railway bridge in the world and was completed in 1877. There are several articles about it in The Engineer, written by those untainted with knowledge of the disaster to come. Here are a few snippets.

9 October 1872, North side

1872taynorth1

Valentine’s day, 1873, South side

1873taysouth1

The principal article about the construction, published on 4 April, 1873 (p200ff), carries several illustrations. The article starts with:

THE TAY BRIDGE. We make no apology to our readers for this week devoting all our cut pages to illustrations of the most important civil engineering work now being carried out in Great Britain. Indeed, the magnitude of the bridge, and the novelty and ingenuity of the means employed in its erection, entitle it to take rank with the most interesting civil engineering works ever carried to completion. The Tay Bridge will be, when finished, the largest iron bridge in the world. Since the town of Dundee has grown to its present manufacturing importance, the great want of a bridge to connect the existing North British Railway system in Fife directly with the town of Dundee has been severely felt. At present, the whole of the coal, goods, and passenger traffic coming by the North British line has to be conveyed across in steamers to Tay Port, and thence over the Caledonian Railway to Dundee, involving not only great expense for maintenance, but frequent delays from the enormous accession of traffic, and the stormy winter weather.

Sinking the Caissons

1873taycaissons1

Floating the Piers

1873taypierfloats1

Skipping forward to a report in The Engineer of 22 June 1877 (p433), this appears to have been reprinted verbatim (apart from a minor equivalence of ‘on Wednesday’ and ‘yesterday’) from The Times of Thursday, June 21st, 1877 (p9)

FATAL ACCIDENT. – An accident by which one man was instantaneously killed occurred at the Tay-bridge on Wednesday evening. While a span was being lifted to the top of two piers one of the chains used in hoisting it snapped. Immediately the huge piece of iron, which weighed 25 tons, was released, the chain suspending the other end gave way, owing to the sudden jerk. In its descent into the river, from a height of 50ft., the span struck one of the workmen named Bain and killed him on the spot. Besides the pecuniary loss, which is considerable, the accident will have the effect of interrupting the progress of the works, which were proceeding most satisfactorily. The engineers are, however, confident that, notwithstanding what has happened, they will be able to complete their arrangement with the Tay Bridge Company to run a train over the structure on the 15th of September next.

Another report, near completion, is a brief article from The Engineer of 7 September 1877 (p172)

THE TAY BRIDGE. THERE has recently been considerable progress made with this work. All the girders have been lifted to their position, and the bridge has therefore quite a finished appearance. It is expected that in the course of two or three weeks a train will be run across from the Fifeshire end to Dundee. The station in connection with the bridge line will not be completed for a few months, so probably some time must elapse before the commencement of public traffic. Messrs. Hopkins, Gilkes, and Co., the contractors, must be congratulated upon the successful position of this difficult undertaking. It will be remembered that last February, during the severe storm that raged over the northern part of the country, two of the large girders were blown down, and with them the upper parts of two of the piers. Taking this into account with the late inclement summer season, it has required considerable energy on the part of the engineers in charge of the work to complete it so nearly within the estimated date. At some future time we purpose giving details of some of the most interesting parts of the work. We recently published an account of a novel system of excavating, introduced by Mr. Reeves, which greatly facilitated the sinking of the pier foundations. As the opening of this bridge approaches an increasing number of visitors have been received. Last Saturday General Grant and Sir Jas. Falshaw, with a party, went up from Edinburgh by special train to see the bridge. They were received by Mr. Gilkes, and they expressed themselves much pleased at the appearance of the structure, which now 1ooks very well, with the fine scenery in the background.

A longer article, again from The Engineer (28 September 1877 (p228)) describes dignitaries having a first ceremonial train ride across the two miles of river. The line wouldn’t be open to the public until the station was completed a few months later.

THE TAY BRIDGE – On Tuesday the Tay Bridge was virtually opened for traffic, that is to say, a long train containing many of the directors of the North British Railway and other gentlemen, was run across the bridge from the south to the north side. A great concourse of people was present to see the Tay crossed by a railway train. The connecting works are not yet complete, but in a very short time all will be ready for Board of Trade inspection, and the bridge will then be opened for traffic. An elaborate description of this bridge, fully illustrated will be found in THE ENGINEER for April 4th, 1873, and to this we must refer such of our readers who are desirous of complete information concerning the longest railway bridge in the world. But a few general particulars concerning the structure, and a glance at its history, will not be out of place here.

The bridge has been constructed to carry the traffic of the North British Railway across the estuary of the Tay at a place where it is nearly two miles wide. It was designed by Mr. Bouch, C.E., and a bill was obtained in 1870 for its construction. Messrs. De Bergue and Co., of London, obtained the contract for it in 1871, and the foundation-stone was laid in the land abutment on the south side on the 22nd July of the same year. In May, 1874, the death of the principal partner of De Bergue and Co. led to the transference of the contract from that firm to Messrs. Hopkins, Gilkes, and Co., Middlesbrough, by whom it has since been prosecuted and finished. The bridge begins about a mile and a half above Newport, on the south side of the river, where the depth of water at high spring tides is 45ft., the velocity of the current reaching occasionally five knots an hour. The design includes eighty-five spans, varying in length from 67ft. to 245ft., those of the greatest dimensions being placed over the navigable part of the river. Here the bridge has a clear height of 88ft. above high water, from which it slopes down to the Fife side with a gradient of 1 in 356, and towards the Dundee side where it takes a curve to the eastward in order the more conveniently to join the land line, with a gradient of 1 in 73. We must refer our readers to THE ENGINEER for April 4th, 1873, for a description of the method of erecting the bridge adopted by Messrs. De Bergue. After the work had been in progress for some time on this system, it was found that the rock suddenly shelved away to a great depth under beds of clay gravel, and sand. It therefore became impracticable to sink the piers to that foundation, and a new method had to be introduced. The weight of the pier was lightened by substituting in the upper works iron columns for solid brick, while the adoption for each pier of a single oval cylinder measuring 23½ft. by 13½ft. secured a larger bearing than had previously been obtained with two smaller ones. The cylinders, constructed on shore, were floated out to their places, and sunk by the aid of an ingenious sand pump invented by one of the assistant engineers, Mr. Reeves. The interior of the cylinder was afterwards filled to the top with cement concrete, and the portion above the bottom of the river being removed, on the concrete was placed a base for the pier constructed on shore and floated out. This reached to the level of low-water, and on it, as the tide permitted, men worked at the erection of the next section which reached to high-water mark, where four courses of stone were fixed. On these were placed the iron columns, 12in. and 15in. in diameter, carrying the girders.

When the piers had been brought up to the proper height, the girders – measuring 245ft. in length, and weighing 190 tons for each span — were towed out. The raising of the girders was carried on in lifts of 20ft. at a time by hydraulic apparatus. Two girders, connected by transverse braces, go to each span, the depths varying according to the width of the space to be crossed. The length of the spans diminishes in going towards the shores on either side of the navigable channel, the depths of the girders being correspondingly decreased, the minimum being 12ft. The bridge has been calculated for a rolling load of 1½ ton to the foot run. The bridge is connected with the main line of the North British Railway by a branch striking off at Leuchars Junction, and running up to the south end of the bridge, the distance being about five miles.

During the construction of the bridge very serious difficulties were encountered, caused in a great measure by the enormous height of the structure above water, in a situation where it is exposed to heavy gales. This height was considered necessary to prevent the passage of ships being stopped, but it has been found, as a matter of fact, that the number of ships which require a headway of 80ft. at low water is nominal; and there is no reason to doubt that no harm would have been done, while a vast sum would have been saved, had the bridge been made 30ft lower than it is. We heartily congratulate the engineers, contractors, and proprietors on the successful completion of a thoroughly great work.

And down it all comes only a couple of years later, removing from the planet one complete train and at least 60 humans with it.

Advertisements

About pussonalamp
Aged SemiWit

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: