Gauge change technology hopes to overcome European differences
Engineer Live ! Rail Industry International: August 28, 2006
Due to historic developments rail networks throughout Europe use different track gauges. here, Matthias Schwartze reports on the construction of the DBAG/Rafil Type V gauge change wheel set which is design to provide an automatic transfer from one gauge to another.
In most of the European countries the gauge of 1435mm is used, which is also called normal gauge. In the countries of the former Soviet Union, in the Baltic countries and in Finland, the broad gauge of 1520mm is used. On the Iberian peninsula, a broad gauge with a gauge of 1668mm (Spain) or of 1665mm (Portugal) is used. Moreover, in Ireland a broad gauge of 1600mm is applied.
Due to an increased exchange of goods and public transport these limited systems represent an essential hindrance. The technologies of transferring from one gauge to the other one, which are normally practised at present, are that the passengers have to change the trains or that the goods have to be loaded on other trains or that the bogies or wheel sets are changed.
An alternative to this technology is represented by gauge changing systems, which provide for an automatic transfer from one gauge to another one. Gauge changing systems require special technical solutions both at the vehicle as well as at the permanent way at the intersection of the gauges. The so-called gauge change wheelset forms the centrepiece in the vehicle. A stationary gauge changing equipment forms the connection between the gauges.
Based upon the results of studies on economic efficiency and need performed by the German Railway (DBAG) and the UIC study group of gauge change wheel sets, the development of such wheel sets has been taken up again in 1995. The German Railway and the wheel set factory Radsatzfabrik Ilsenburg GmbH (RAFIL)concluded a contract on the further development of the DRIV gauge change wheel set including the construction of prototypes for the gauges of 1435/1520mm and 1435/1668mm. The prepared technical specifications contains the essential criteria, which should be considered during the development.
The DBAG/Rafil TypeV change gauge wheel set consists of a wheel set shaft and two axially displaceable solid wheels, which are joint to the shaft by a locking system. The solid wheel has been derived from the well-proved solid wheel of the 004 type of DBAG. It has got an adequately long wheel hub to guarantee the functions of locking and unlocking and the transmission of power and moment. A special plastic bush is pressed into the wheel hub.
The axle has been derived from the well-tried constructions for goods wagons. It has been equipped with prolonged wheel seats and seats for taking up the coupling star. If necessary, there are seats for brake discs realised, too.
The torque transmission is performed by a clutch coupling between wheel and wheel set shaft, which does not hinder the axial displacement. The axial securing is done by a locking mechanism, which consists of unlocking disc, locking sleeve, locking levers and compression springs. Hereby, the locking levers are pressed into the respective grooves of the cams, which, on the other hand, are firmly connected with the wheel. The basic technical data can be summarised as shown in Fig. 1.
The changeover is done while the wheel sets are driving over a special gauge changeover equipment with a low speed of about 5 to 10km/h. The process of gauge changeover is done under full load of the wheel sets and uninterruptedly from normal gauge to broad gauge and vice versa. Depending on the gauges a respective stationary gauge changeover equipment is needed having a length of 16m or 28m.
After the gauge has been changed the position of the locking sleeve is checked by an appliance that is installed at the plant. This guarantees that only those gauge change wheel sets leave the plant the wheels of which are safely connected to the wheel set shaft.
Equipment of the vehicles
So that a vehicle can change the gauge without any obstacles there are some more components needed at the vehicle in addition to the wheel set. General for the transition from normal gauge to both the broad gauge a brake block changeover arrangement is necessary for vehicles with block brakes. For the transition from normal gauge of 1435mm to broad gauge of 1520mm the components KE-Matrossow 483 triple valve combination and Composite coupling SA 3/Screw coupling have been additionally developed. These vehicle components can be applied to all types of vehicles.
It is fixed in the UIC leaflet no. 510-4 and the specification for the development and testing of undercarriages for goods wagons for the gauge 1435mm/1668mm which calculations and tests have to be performed for getting an admission.
On the basis of the results of the investigations according to these leaflet existing so far we can assess that:
* The calculations and tests at the test stand have showed a sufficient strength of the wheels, of the wheel set shaft and the components of the locking mechanism.
* From the point of view of travelling and braking technology an application of the wagons that are equipped with gauge change wheel sets is possible for empty and loaded wagons with 22.5t of wheel set load and 120km/h.
* The functional safety has been proved under all climatic conditions of application.
* The proper locking of the wheels has been always guaranteed during over-running tests, driving over track torsions and under the influence of high longitudinal pressing forces.
* There is no impairment of the locking mechanism caused by a high thermal strain on the wheels due to permanent braking.
* The reasons of the irregularities, which have been sometimes stated during the operational tests (inner and outer sealing system, once an irregular locking), could be determined and the respective amendments were realised.
* The determination of limits as to the admissible wear of the components could be done after the completion of the entire operational tests only.
After completing the current tests in service the admission will be probably reached by the end of this year. The manufacturers of vehicles and their operators have already showed their interest in applying the gauge change technology for the traffic to Spain and in Scandinavia.
Dipl-Ing Matthias Schwartze is with Radsatzfabrik Ilsenburg GmbH, Ilsenburg, Germany.