BACKGROUND OF THE INVENTION

The invention relates to the issues with slippery rails for trains. The slipperiness is caused by the build-up of a layer of slippery material or deposit on the rails through exogenous influences.

A first known example is slipperiness caused by leaf fall in the autumn, wherein leaves end up on the rails and under the influence of humidity and passing trains riding over them the leaves change into a slippery layer of biological material. This slipperiness occurs during specific times of the year.

Further examples are a deposit caused by settling soot particles from exhaust fumes, substances from industry, iron oxide particles as a result of trains decelerating or grinding dust from the overhead power lines and the pantographs. This may also occur in combination with the above-mentioned leaf fall. In certain countries slipperiness is caused by colonies of snails that crawl over the rails being squashed.

Due to the slipperiness the wheels of the trains skid during braking and the wheels spin during accelerating or starting up. This leads to damage to the wheels and rails, it compromises the punctuality of the timetable and increases the risk of passage through a red signal and accidents.

Various attempts have been made to combat the slipperiness of rails as a result of a layer of slippery material or deposits, such as applying a friction enhancing gel and cutting back vegetation along the railroad by way of prevention. The results, however, were not satisfactory.

It is an object of the invention to provide a method and facility with which the above-mentioned slipperiness can be counteracted effectively.

SUMMARY OF THE INVENTION

According to one aspect the invention provides a method for conditioning a railroad for a train with a station or stop location for the train, wherein a deceleration section and/or an acceleration section for the train has been defined over the railroad, wherein the deceleration section regards the distance over the railroad reguired for bringing the approaching train to a standstill at the station or the stop location and the acceleration section regards the distance over the railroad required for speeding up the train departing from the station or the stop location, wherein the railroad comprises a left rail and a right rail that are parallel to each other and are both provided with a top surface for contacting the wheels of the train, and wherein the railroad is provided with a fixed moistening device for moistening the top surface of the left rail and the right rail, wherein the method comprises by means of the moistening device supplying and keeping the agueous fluid present on the top surface of the left rail and the top surface of the right rail distributed over at least a part of the deceleration section and/or acceleration section.

By supplying and keeping the aqueous fluid present on the top surfaces of both rails over the said distance it can be counteracted that over the said distance a layer of biological material or another deposit adheres to the rails. On the other hand a grown layer of biological material or another deposit can effectively be dissolved and flushed away. Trains that may pass by will then even have a rubbing effect. The trains can maintain the nominal braking and accelerating distance over this clean railroad.

Attachment and build-up of a layer of biological material or another deposit can particularly be counteracted if by means of the moistening device the aqueous fluid is kept continuously present on the top surface of the left rail and the top surface of the right rail.

In one embodiment defined according to quantity, by means of the moistening device the aqueous fluid is kept present on the top surface of the left rail and the top surface of the right rail for at least one week.

In a second embodiment defined according to quantity, by means of the moistening device the aqueous fluid is excessively supplied for at least one hour and the top surface of the left rail and the top surface of the right rail are flooded with the supplied aqueous fluid. The excessive supply ensures that a layer of biological material that is already present is dissolved and discharged from the top surfaces of the rails.

In an aqueous fluid-saving embodiment supplying the aqueous fluid by means of the moistening device is interrupted during a rain shower.

In a practical embodiment the aqueous fluid is water. It can for instance be taken from the water supply system or from a subterranean water source.

In one embodiment the railroad is provided with a moistening device for moistening the top surface of the left rail and the top surface of the right rail, wherein the moistening device comprises a fluid guide extending along the railroad and a supply of an aqueous fluid to the fluid guide, wherein the fluid guide is provided with several outflow openings distributed along the left rail and along the right rail for discharging the aqueous fluid, wherein the outflow openings are distributed over at least a part of the deceleration section and/or the acceleration section.

In one embodiment the outflow openings along the left rail and along the right rail are distributed over the largest part of or the entire deceleration section and/or the entire acceleration section, so that normal and even deceleration and acceleration is possible over said entire distance.

Formulated according to quantity the outflow openings along the left rail and along the right rail are distributed over at least 80% of the deceleration section and/or the acceleration section.

The deceleration section and/or the acceleration section as regards length correspond with the legally standardized deceleration section of a train under normal conditions without exogenous influences on the top surface of the left rail and the right rail.

In one embodiment defined according to quantity, the outflow openings along the left rail and along the right rail are distributed over a distance of at least 200 metres before and/or after the station or the stop location.

Especially the outflow openings along the left rail and along the right rail are distributed over a distance of at least 400 metres before and/or after the station or the stop location.

More particularly the outflow openings along the left rail and along the right rail are distributed over a distance of at least 800 metres before and/or after the station or the stop location.

In one embodiment the fluid guide comprises a left conduit extending along the left rail and a right conduit extending along the right rail. The left conduit and the right conduit can be arranged along an existing railroad. In one embodiment thereof the left rail and the right rail are provided with a foot, a body and a head on top of which the top surface is situated, wherein the left conduit and the right conduit are attached against the head of the left rail and the head of the right rail, respectively.

According to a second aspect the invention furthermore provides a railroad for a train with a station or stop location for the train, wherein a deceleration section and/or an acceleration section for the train has been defined over the railroad, wherein the deceleration section regards the distance over the railroad reguired for bringing the approaching train to a standstill at the station or the stop location and the acceleration section regards the distance over the railroad required for speeding up the train departing from the station or the stop location, wherein the railroad comprises a left rail and a right rail that are parallel to each other and are both provided with a top surface for contacting the wheels of the train, wherein the railroad is provided with a moistening device for moistening the top surface of the left rail and the top surface of the right rail, wherein the moistening device comprises a fluid guide extending along the railroad and a supply of an aqueous fluid to the fluid guide, wherein the fluid guide is provided with several outflow openings distributed along the left rail and along the right rail for discharging the aqueous fluid, wherein the outflow openings are distributed over at least a part of the deceleration section and/or the acceleration section.

The moistening device can supply the aqueous fluid to the top surfaces of both rails over at least a part of the deceleration section and/or the acceleration section. On the one hand, due to a prolonged continuous presence of for instance a few weeks, the aqueous fluid is able to counteract that a layer of biological material or another deposit adheres to the rails. On the other hand, in case of excessive supply of the aqueous fluid, a grown layer of biological material or another deposit may effectively be dissolved and flushed away. Trains that may pass by will then even have a rubbing effect.

In one embodiment the outflow openings along the left rail and along the right rail are distributed over the largest part of or the entire deceleration section and/or the entire acceleration section, so that normal and even deceleration and acceleration is possible over said entire distance.

Formulated according to quantity the outflow openings along the left rail and along the right rail are distributed over at least 80% of the deceleration section and/or the acceleration section.

The deceleration section and/or the acceleration section as regards length correspond with the legally standardized deceleration section of a train under normal conditions without exogenous influences on the top surface of the left rail and the right rail.

In one embodiment defined according to quantity, the outflow openings along the left rail and along the right rail are distributed over a distance of at least 200 metres before and/or after the station or the stop location.

Especially the outflow openings along the left rail and along the right rail are distributed over a distance of at least 400 metres before and/or after the station or the stop location.

More particularly the outflow openings along the left rail and along the right rail are distributed over a distance of at least 800 metres before and/or after the station or the stop location.

In one embodiment the fluid guide comprises a left conduit extending along the left rail and a right conduit extending along the right rail. The left conduit and the right conduit can be arranged along an existing railroad.

In one embodiment thereof the left rail and the right rail are provided with a foot, a body and a head on top of which the top surface is situated, wherein the left conduit and the right conduit are attached against the head of the left rail and the head of the right rail, respectively.

In one embodiment the left conduit and the right conduit are both provided with the outflow openings, wherein the outflow openings preferably are oriented to the top surface of the rail. After having been discharged from the outflow openings, the aqueous fluid can then flow out directly over the top surface of the rail .

In one embodiment the left conduit and the top surface of the left rail together bound a left fluid bath and the right conduit and the top surface of the right rail together bound a right fluid bath, so that the aqueous fluid can remain prolonged on the top surfaces of the rails for the above-mentioned preventive action.

In one embodiment the left rail and the right rail are provided with a foot, a body and a head on top of which the top surface is situated, wherein the left conduit and the right conduit are attached against the outer side of the head of the left rail and the right rail, respectively, which outer side faces away from the railroad, so that they will not contact the wheels of the trains passing by.

In one embodiment the supply of the aqueous fluid is provided with a control for switching on and switching off the supply of the aqueous fluid to the fluid guide.

The aspects and measures described in this description and the claims of the application and/or shown in the drawings of this application may where possible also be used individually. Said individual aspects may be the subject of divisional patent applications relating thereto. This particularly applies to the measures and aspects that are described per se in the sub claims.

SHORT DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of a number of exemplary embodiments shown in the attached drawings, in which:

Figure 1 is a schematic overview of a railroad including a moistening device according to the invention;

Figure 2 is an isometric view of a part of the railroad; and

Figures 3A and 3B show the same cross-sections of the railroad section and the moistening device.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 schematically shows a railroad 1 along which a station 10 having a platform 11 is situated. Trains 12 come to a standstill alongside the platform 10 and depart in the same direction or in opposite direction. For a train 12 arriving in direction A and departing in the same direction A a deceleration section or braking section R and a start- up section or acceleration section V is defined.

The deceleration section R is technically dictated and is the shortest distance over the railroad 1 required for under normal conditions allowing a train to decelerate from the locally allowed maximum speed to a standstill. A train keeps said maximum speed as continuous section speed for the larger part of a section between two stations. Based on legislation detailed standards have been laid down as regards the deceleration section R. Said standards were laid down on the basis of technical calculations in which deceleration tables and brake weights of trains were included. In principle said standards are determined nationally, but where required they are internationally adapted in connection with cross-border traffic. The maximum deceleration path in this case dictates the maximum continuous section speed and vice versa.

In the Netherlands for a speed of 0-40 km per hour a deceleration section of 400 meters applies. For a maximum speed of 40-60 km per hour a deceleration section of 500 meters applies. For a maximum speed of 60-80 km per hour a deceleration section of 800 meters applies. For a maximum speed of 80-130 km per hour a deceleration section of 1000 meters applies. For a maximum speed of 130-160 km per hour a deceleration section of 1150 meters applies. This means that a train at the said speed should activate the brakes ultimately before the prescribed distance to the stop location. Summarizing the deceleration section therefore has a length of at least 400 meters, preferably at least 800 meters .

The acceleration section V is also technically dictated and is the distance over the railroad 1 that a train requires to reach its continuous section speed from a standstill at platform 11. The length of the acceleration section depends on the continuous section speed to be reached. As the deceleration forces and acceleration forces of trains are both largely dictated by the friction conditions between the railroad and the wheels, the length of the acceleration section V for the same continuous section speed approximately corresponds with the length of the deceleration section R. Due to distribution of the driven and braked wheels over the length of a train, the acceleration section V and the deceleration section R may have an overlap at the location of the station 10. In figure 1 the deceleration section R and the acceleration section V are indicated with respect to the nose of the train 12.

As shown in figure 1 a railroad 1 is built up with a left rail 21 and an identical right rail 22 that are attached parallel to each other on sleepers 23 in a track bed. The left rail 21 is shown in detail in figure 3A and 3B. The steel rails 21, 22 in this example are of the common Vigole type and comprise a body 26, a foot 27 and a head 25 having a bulging top surface 26. A train wheel 60 comprises a tread 61 that runs over the top surface 26 and a flange 62 that guides the train wheel 60. The contact area 28 at the top of the top surface 26 has a width B that is a fraction of the width of the head 25. The width B of the contact area is only a few millimetres.

The deceleration section R and the acceleration section V can be extended for a same continuous section speed as a result of adverse exogenous influences, such as a layer of a biological material resulting from leaf fall that has grown and been driven stuck onto the head 25 of the rails 21, 22. The natural conditions under which this occurs are known and can be predicted well. The biological material may multiply the length of a deceleration section R or acceleration section V with respect to the regular conditions with clean rails 21, 22 on which the aforementioned standards have been based. In order to counteract these problems a railroad 1 has been provided with a moistening device 40. The moistening device 40 is a fixed installation on the railroad 1.

As shown in figure 1 the moistening device 40 comprises a plastic left conduit 41 extending along the outside of the head 25 of the left rail 21 and a plastic right conduit 42 extending mirror-symmetrically along the outside of the head 25 of the right rail 22. The left conduit 41 and the right conduit 42 are identical and attached in the same manner against the left rail 21 and right rail 22, respectively. The left conduit 41 and the right conduit 42 extend over the standardised deceleration section R and the acceleration section V. The left conduit 41 and its attachment are shown in detail in figures 3A and 3B.

The left conduit 41 comprises a plastic body

43 having an abutment surface 44 abutting the side of the head 25. At the top side the left conduit 41 is provided with a curved top surface 45 underneath which a continuous supply duct 47 has been formed. In the left conduit 41 several discharge ducts 46 have been formed that are distributed over the length of the left conduit 41 and extend upwardly inclined from the continuous supply duct 47 in the direction of the top surface 26 of the head 25. The left conduit 41 is attached to the left rail 21 by means of several metal clamps 49 distributed over the length. The clamps 49 engage onto the foot of the left rail 21 and clamp the left conduit 41 with the abutment surface 44 in a liquid-tight manner against the side of the head 25. In vertical direction the top side of the curved top surface 45 is at the level of, or a few millimetres above, the contact area 28. As shown in figure 3B the left conduit 41 in this position is not hindered by a passing train wheel 60. The curved top surface 45 of the left conduit 41 together with the top surface 26 of the left rail 21 forms a water channel 50 extending along the head 25.

As shown in figure 1 the moistening device 40 comprises a water pump 51 the entrance of which is connected to a supply conduit 52 for instance from a schematically shown ground water source 53. The exit of the water pump 51 is connected to a supply line 54 with a first branch 55 to the left conduit 41 and a second branch 56 to the right conduit 42. The water pump 51 is connected to an electric control in a control cabinet 57. The control cabinet 57 is provided with a rain sensor. The electric control is in connection with the traffic control room of the railroad 1. The electric control is adapted for actuating the pump 1 at several flow rates and over various periods.

During favourable conditions without adverse exogenous influences the wheels 60 have optimal contact with the rails 21, 22. These conditions occur the larger part of the year, usually in the winter, the spring and the summer. The build-up of a biological layer as a result of leaf fall typically only occurs during a period of a few weeks in the autumn, in which a properly predictable combination of leaf fall, wind, temperature and humidity is required to form the biological layer.

The action of the moistening device is as follows :

During the favourable conditions in which the wheels 60 have optimal contact with the head 25 of the rails 21, 22 the pump 51 is switched off. When it is expected in this example that the natural conditions will change such before long, that a layer of biological material may arise on the head 25 of the rails 21, 22, the pump 51 is actuated so that water is supplied to the left conduit 41 and the right conduit 42. The water leaves the continuous supply duct 47 via the discharge ducts 46 as a result of which a water bath 51 is created over the length of the deceleration section R and the acceleration section V, which water bath flows out over the contact area 28. The water may optionally drip down at the opposite side of the top surface 26. The control ensures that during the period of a few weeks in which a layer of biological material may arise as a result of leaf fall, the pump 51 keeps supplying sufficient water to keep the top surface 26, particularly its contact area 28, continuously moist or wet, but the dripping is limited to a minimum in order to prevent excessive penetration of water into or saturation of the underlying track bed. During a rain shower registered by the rain sensor the pump 51 may temporarily be stopped due to the in that case natural supply of water on the top surface 26. When trains are passing the pump 51 may temporarily be stopped because the train 12 will cause the supplied water to splash immediately. The top surfaces 26 still remain moist, which is considered as the continuous presence of water or aqueous fluid.

Keeping the top surface 26 moist or wet results in no biological layer being able to adhere to or build up on the top surface 26. The same goes for attachment of a deposit of for instance soot or iron oxide particles. Passing trains even have a polishing effect. The presence of water on the contact area 28 has no adverse effects on the grip of the train wheel 60 on the rails 21, 22. The water present, together with the loosened biological material and other deposits, are removed by the moving train.

In case the natural conditions have unexpectedly changed so quickly that a layer of biological material has arisen on the top surface 26 of the rails 21, 22, then the pump 51 is able to supply water at an increased flow rate for 1-3 hours as a result of which the top surfaces 26 are excessively flooded. This dissolves the biological layer or deposit and removes it.

The above description is included to illustrate the operation of preferred embodiments of the invention and not to limit the scope of the invention. Starting from the above explanation many variations that fall within the spirit and scope of the present invention will be evident to an expert.