Variable gauge axle systems
Variable gauge axle systems
One of the main problems in the further development of international railway traffic in Europe is overcoming the borders between countries with different gauges. The solution to this problem can be variable gauge axle systems.
At first, the railway transport in each country was developed taking into account only national interests and did not take into account the peculiarities of the railway track of other countries. Therefore, now most of the states of Western Europe have a gauge of 1435 mm, Spain – 1668 mm, Portugal – 1665 mm, Finland – 1524 mm, and the countries of the post-Soviet space have a gauge of 1520 mm.
The problem of switching from one gauge to another began to be solved at the beginning of the twentieth century. At the border stations between the Russian Empire (and later the USSR) and Europe, the main transition technology was the transfer of passengers and the transshipment of goods. This required additional costs and significantly increased the time spent by the trains on the way.
A faster way to change from one track gauge to another is to reload large cargo units – containers, piggybacks, etc. However, even such reloading is still less efficient compared to rearranging cars on bogies for a different gauge. There are also wheelset replacement technologies.
But now, the most effective way to overcome borders between countries with different track gauges is to use variable gauge axles, a system that is capable of changing the width without stopping the movement of the train on special transfer track devices.
Considering the need to develop international rail passenger traffic between Spain and France, the Spanish company Talgo in 1965 began developing a new system for automatically changing railway wheels to a different gauge.
The practical application of variable gauge axles began in 1969, when the first Talgo RD passenger train arrived from Barcelona to Geneva. Talgo variable gauge axle systems for passenger rail cars have been tested and are successfully operating at the present time, reaching a high technological level.
The Talgo system is based on the forced displacement of individual wheel blocks, which is carried out during the movement of a railway car. Each of the blocks consists of a wheel with brake discs, a short axle and tapered roller bearings. There is no single axle in this design, that is, there is no wheelset in the traditional sense of this term.
The wheels move in an unloaded state. When the load is removed from the wheels, they cease to contact the wide track rails. This is due to the fact that the supports, which are located on the outside of the outer bearings, slide on the support rails of the stationary installation (the height of which gradually increases) and move along them using water as a lubricant. At the same time, the T-shaped guides of the stationary installation go into the corresponding grooves of the locking devices of the wheel assemblies and move the bearing fastening locks. Railroad wheels with bearings are released.
The guide rails of the stationary installation converge, acting on the outer edges of the wheels, and move them in the transverse direction of the axis to a position corresponding to the width of the new track. The T-shaped guides re-enter the grooves of the locking devices, returning the bearing locks to their place, and the wheels are fixed in a new position. The height of the support rails decreases slowly. The sliding stops come off them, and the wheels, which are in the corresponding position, are lowered onto the 1435 mm track gauge. The process works in a similar way and in the opposite direction.
Talgo has also developed a similar automatic changeover system from a 1668 mm track to a 1435 mm track and vice versa for freight cars.
The first systems of variable gauge axle also include joint projects of the Bryansk Machine-Building Plant and the Ural Carriage Works, as well as the development of German specialists. Later, a system of sliding wheelsets developed in Bulgaria appeared on the basis of a standard bogie for a 1435 mm gauge track.
In Poland, the SUW 2000 system was developed, which allows the wheelset to quickly adapt to the three track standards common in Europe, when driving at a speed of 30 km/h. But as of 2016, the implementation of the system through a number of bureaucratic, technical obstacles is almost never done. The borders of Poland are equipped with this system in only three places. There are several trains and rail buses on both sides on the Polish-Ukrainian border that use the SUW 2000 system.