A Modern Steel Process that Facilitates repairs and Construction
22,000 FT OF WELDING -
AMONG modern metallurgical developments the welding of steel is increasingly claiming the attention of railway engineers. In maintenance work the use of welding is becoming common in effecting repairs and building up worn parts, and it is also being pressed into service in the fabrication of steel structures and in building rolling stock. Its chief advantages in the latter connexion are that riveting is dispensed with and weight is reduced. Weight reduction in the rolling stock realm is, of course, of primary importance, as the lighter the train the less the power required for its propulsion. Several of the latest high-
In Great Britain the most commonly-
Here, because a flange-
Where tracks cross one another at right angles, or nearly so, the wheels must pass over a clear gap in the rails 1¾ in in width, or thereabouts. But right-
In earlier days, when the point of the crossing had thus become depressed and the wing rails deeply grooved, there was no alternative to taking up the whole crossing and substituting another, or at least to replacing all the four rails. This was a costly business. Now, however, welding, which can be carried out a number of times in succession on the same crossing, defers indefinitely such replacements. A portable apparatus, self-
It is now the custom to build on to the rails alloy steels considerably harder in quality than the steel of which the rail was
originally composed, so that the welded rail surface is thus of a better wearing quality than the rail was before welding. The
process is not entirely without risk, as great care has to be taken that in the violence of the heat treatment so applied the rail is not made brittle.
In America welding is used also to build up the ends of the rails at the joints. Axle-
enormously heavy that the rails get badly “battered”, or worn down, at the joints, and certain railways have now created a travelling organization of men who go round building up these joints with welding apparatus. This, of course, is a vastly bigger job than merely building up worn crossings, for whereas it is possible to travel for several miles without passing over a single crossing, there is a joint in each rail at 33 ft or 39 ft intervals on American tracks.
This brings us to another application of welding in the track which to a large extent does away with rail-
than of expansion.
THE UNDERFRAME of an all-
In Germany rails of a standard length of 30 metres (98 ft 5 in) are now produced as a regular practice in the rail-
The most remarkable experiment of this description that has yet been performed has been in Germany. In the Brandleite Tunnel, on the main line between Berlin and Stuttgart, which is nearly two miles long, the rails of the double track have been welded into four continuous lengths, each 2,640 metres, or 8,662 ft long. Even starting with 30-
would be needed, and if this had all to be done in the tunnel, with bad atmospheric conditions, the task would have been intolerable.
It was therefore decided first of all to weld the 30-
The problem was solved successfully by loading them on sets of six bogie wagons, twenty-
In this way, therefore, 288 of the welds were made in comfortable and convenient conditions at the Neutiedendorf depot, and it was only necessary to make sixty welds, fifteen in each run of rail, in the tunnel. As flash-
apparatus, which could not be used in the tunnel, it was necessary to make the final welds in the tunnel by the “thermit” welding process. At the two ends of the Brandleite Tunnel, where slight variations of temperature may be looked for, the 8,662 ft of the continuous rails is flanked by about 650 ft of ordinary rails, jointed in the usual way.
Application to Bridges
Another application of welding which is being applied on a constantly increasing scale is to bridges. There are numerous railway bridges in which the various plates and rolled sections used in building up the girders have been united, not by riveting, but by welding. One great advantage of this welded construction is that all the drilling of rivet-
The same principle is applied also in bridge repairing. An outstanding example of this treatment on a large scale is found in the work which was carried out recently by the LMS Railway on a viaduct which carries the main line of the Midland Division
across the River Ouse just south of Sharnbrook Station, seven miles north of Bedford. The viaduct is of wrought iron girder construction, carried on substantial brick piers It consists of three 60-
Each span consists of six girders; under each rail there is a wrought iron girder 5 ft 6-
across the width of the bridge.
AFTER WELDING. This illustration shows a wing rail being brought to the correct profile after electric-
As the bridge is in the middle of the well-
It was therefore decided thoroughly to repair and strengthen the viaduct. Among other changes were the substitution of steel floor-
A special welding plant of the “Quasi-
308 amperes for one hour, or 246 amperes indefinitely, the voltage remaining constant at 50 volts. By the use of three reactances, each dynamo was arranged to supply current to three welders simultaneously, and each operator was supplied with a resistance regulator, by which he could adjust the current to suit the particular size and type of electrode that he had in use. The total amount of welding, mostly double run, amounted to 22,000 feet over the whole length of the viaduct, and no fewer than 66,400 electrodes, each 18 inches long, were used up before the work was completed. The auxiliary dynamo, another compound-
A Two Years’ Task
It has to be appreciated that the whole of the work work was carried out without any interruption to traffic, except on four Sundays, when the passenger trains were temporarily diverted to the adjacent goods lines. This diversion was necessary when the girders were lifted three inches vertically off their worn bedstones, so that new steel bearing plates, one inch thick,
might be inserted between the girders and their original beds, and the worn spaces in the bedstones filled up. The girders were then lowered again into position. As six pairs of girder-
complex operation was completed in no more than four Sundays in all.
Of the new steel floor-
The average time taken to complete the work on each span was about four weeks. Careful observation was taken to see that no leakage of water was taking place through the floor-
The whole of the operation, which took two years to complete, reflects great credit on the engineering staff responsible for the smoothness with which it was carried out.