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This was a small 'four poster' lifting bridge carrying a roadway (with tramlines added later) over the Wilts and Berks Canal, flanked by two footbridges.
It was demolished in 1918, several years after closure of the canal.
1870 'Sir,— After many years of inconvenience arising from that hideous incline and bridge at the Golden Lion Inn, we are, I am glad to hear, shortly to have a new bridge and the level of the roadway reduced. The one to be placed there is what I shall term an Equilibrium Bridge, and it will very much resemble a gasometer. There are to be four cast iron hollow columns standing some eight and a half or more feet above ground, with weights working inside to balance the weight of the bridge. Two of these columns are to be placed on each side of the canal and will serve to guide the bride in its upward and downward movement. This bridge, with its necessary shafts, bevil wheels, chains, &c., &c., will make it a somewhat complicated, expensive, and by no means a handsome one for such a situation. The floor of the bridge will be worked upwards by turning a handle, which will allow boats to pass, the width is to be increased, but the length (or span) is to be unaltered. The estimated cost of the bride is, I believe, £170, £50 being allowed for constructing two dams and for removing the water between them, £30 for reducing the road level, making £250 the total cost of the improvement. Now, sir, I would suggest first that a floating bridge shall he provided, which simply means a wrought iron tank of suitable dimensions with light-looking lattice work sides to prevent persons from falling into the water, constructed to work in and out of its place with a handle. .... I am, Sir, yours truly, THOS. MIDELTON. 4, Regent Street, New Swindon, Jan. 28, 1870.'
1870 'THE NEW GOLDEN LION BRIDGE, as the chief bridge over the Canal at New Swindon is called, has now been completed, and in the place of the crazy wooden structure of the past we have a handsome erection, pleasing to the eye, safe for use, and of benefit to all. The new bridge is composed entirely of iron and solid masonry. The bridge itself is from the design of Mr. W. Dean [ William Dean?], one of the engineers of the G. W. R. Company, and is five feet and a half wider than its predecessor. It is worked in a very simple but efficient manner. Four cylinders are sunk to a considerable depth each containing iron weights of 15 cwt., all of which are connected with a windlass at the Bridge-street side of the structure. The four weights together weigh nearly as much as the bed of the bridge, which will be raised by means of the windlass aforesaid, to allow barges to pass. The depth of water will be about six feet while the bridge itself is level with Regent-street, and a little more alteration of the road in Bridge-street, which will no doubt be done when the street is again repaired, will render the incline on that side almost nominal. The work as a whole has been admirably executed. The bridge was manufactured in the Great Western Company's Works. Previous to its erection, the water on each aide of the bridge was dammed back, and the water pumped out by the Company's steam fire-engine. The greatest activity was shown in carrying out the work of construction, which was executed under the direction of Mr. William Read, the Surveyor of the New Swindon Local Board, who was unsparing in his labors. The same may be said of the Company's men, and those in the employ of Mr. George Wiltshire, who erected the masonry. In a word, all worked heartily and cheerfully, and public thanks are due to those who took part in providing a much needed accommodation. It almost seems a matter of regret that so large a sum of money and so much time and labor should have been expended in the construction of a bridge over a waterway which must, in the course of a few years, share the fate of other canals in the West of England, i.e., be closed for business, and the bed filled in. The traffic on the Wilts and Berks Canal is yearly lessening, while the decaying state of locks, &c., must render the annual outlay greater in proportion. As an investment the concern is simply a delusion, original shares of £180 returning a dividend about equal to what dealers in Bristol Cattle Market call "dreg 'arf crowns." This is no fault of the original promoters. It is physically impossible for a canal running almost parallel with a railway to obtain traffic which is conveyed by rail more rapidly, much cheaper, and with less labor than by water. The emaciated horses and wretched donkeys which draw the crazy, half-laden boats along the canal seem to be typical of the whole concern.' 
The 1885/6 O.S. map here shows the Golden Lion Bridge taking Bridge Street/Regent Street (which headed in a north easterly direction) over the canal. A short distance to the east, a branch of the canal headed north westwards to pass under various bridges, including [[Bullen's Bridge (Swindon)|Bullen's Bridge) and the railway bridge on the west side of the station.