Railway switch comprising a frog having a movable main point and auxiliary point

In a railway switch comprising a frog having a movable main and auxiliary point, the main and auxiliary point are formed by using thick-web standard rail sections and asymmetric tongue profiles of smaller height as compared with the thick-web standard rail sections which are arranged as outer wing rails. The difference in height between the height of the main and auxiliary points and the height of the outer wing rails is greater than the height of the rail feet of the main and auxiliary points.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention refers to a railway switch comprising a frog having a movable 
main point and auxiliary point. 
2. Description of the Prior Art 
Frogs comprising a movable frog point and comprising a main point and an 
auxiliary point slidingly engaging the main point have, for example, 
become known from German Utility Model Patent No. 69 08 819. For the 
purpose of reliably obtaining the required flexibility of the frog points 
movable relative to one another, a great total length of the construction 
is necessary in such arrangements but the arrangements known up till now 
have a relatively low load carrying capacity and stability of the frog 
point. To achieve the required flexibility of the frog points, it was 
necessary to construct the main and auxiliary points without a rail foot 
over a large portion. This resulted in a severely impeded stability due to 
the reduced bearing surface. Therefore, there were restrictions relating 
to the use of construction materials and with respect to the feasability 
of differing geometrical designs of railway switches. A further drawback 
of the known arrangements resulted from the necessity to provide weld 
junctions and glued junctions in the course of the track, partially at an 
area not being chucked. An additional problem of known arrangements is the 
susceptibility to errors in the shape of the travelling edge. A relatively 
complicated design and a complicated locking system have been necessary 
for movable points known up till now. 
SUMMARY OF THE INVENTION 
The invention now aims at providing a railway switch of the initially 
mentioned type and having a movable frog, in which the switch can be used 
without limitation of construction materials that are usually employed in 
rail construction and in switch construction. The switch of the present 
invention is characterized by a greater load carrying capacity and 
stability, in particular within the area of the frog point. The switch 
according to the invention essentially consists of a main point and an 
auxiliary point that are formed by using standard rail sections having a 
thick web. There are arranged as the outer wing rails asymmetric tongue 
sections that having, as compared with the standard rail sections have a 
thick web, a lower height and being at least partially fixed on base 
plates. On account of using thick-web standard rail sections, the same 
construction material can be used for the main point as well as for the 
auxiliary point, so that uniform wear results and the maintainance costs 
become reduced. By selecting thick-web standard rail sections, the main 
point and the auxiliary point are provided with the required stability, 
and simultaneously, the possibility of elastic staying of the wing rail 
parts is improved. On account of the feature to give the outer wing rails 
a lower height compared with the height of the thick-web standard rail 
sections of the frog and to mount the outer wing rails at least partially 
on base plates, there is provided the possibility to secure the thick-web 
standard rail sections against a lifting movement of their foot portion 
located below the wing rails on occasion of a swivelling movement of the 
frog point. The thick-web standard rail sections thus reliably provide for 
the required strength. On account of the specific design of the outer wing 
rails, lifting movement of the frog point is reliably prevented. Such a 
construction is particularly advantageous in the case of railway switches 
being travelled upon at high speeds in which, when using different 
construction materials such as austenitic manganese steel castings, the 
required junctions or, respectively, track connections cannot be made 
without a high expenditure. On account of avoiding in the construction 
according to the invention a relatively rigid and non-flexible block, a 
more exact shape of the travelling edge can be obtained after having 
finished a switching operation, which is of particular importance in the 
case of high speeds and maximum speeds. An improvement of the exact shape 
of the travelling edge may in principle be achieved by subdividing the 
frog into a main point and an auxiliary point, but the proposals having 
become known up to this time considered the use of tongue sections, which 
resulted in the danger that the points, which have a lower height and have 
been subjected to strong mechanical working operation, are subjected to 
over-stress with respect to their load carrying capacity. The points 
formed of tongue sections must be subjected to mechanical work at their 
front area, so that the sections, which are weak per se, are further 
weakened. 
For the purpose of further reducing the danger of a lifting movement of the 
frog point which already have a greater stability on account of the 
thick-web standard rail sections, the arrangement is advantageously 
selected such that the height of the asymmetric tongue sections having a 
smaller height is smaller for at least the height of the rail foot of the 
thick-web standard rail section of the frog point than the height of the 
thick-web standard rail sections of the frog point. In this manner, it 
becomes possible to shift the frog point, in its respective end position, 
with its foot portion of the thick-web standard rail section below the 
outer wing rails, which results in locking its position. In this case, the 
arrangement is advantageously selected such that the front sides, of the 
base plates, facing the frog point have recesses for gripping over the 
foot of the frog point when contacting the frog point. 
So as not to detract from the stability in those areas in which such 
supporting action against lifting movement can not easily be realized, and 
for the purpose of simultaneously increasing the flexibility of the frog 
point, the arrangement is advantageously selected such that the foot of 
the frog point is, at least within the area of some of the base plates of 
the wing rails, recessed to have a smaller width. 
The use of thick-web standard rail sections for the main point and the 
auxiliary point provides, however, also for a particularly stable sliding 
engagement of the auxiliary point on the main point at the run-off area of 
the frog. For the purpose of increasing the flexibility in such a case, 
there is advantageously selected at this location a sliding connection and 
the arrangement can, in a particularly simple manner be selected such that 
the main point and the auxiliary point are screw-connected by a screw 
extending through their mutually contacting surfaces. The hole provided in 
the main point and/or auxiliary point for the screw is provided with a 
supporting bushing and with spring elements, and is designed as an 
elongated hole extending in a longitudinal direction of the rail section. 
On account of the thick-web standard rail sections being used for the main 
point and for the auxiliary point, any weakening of the section by such 
elongated holes can be allowed without reducing the stability in an 
inadmissible manner. As a whole, there results, on account of this 
measure, a particularly exact shape of the travelling edge within the area 
of the frog point, the shape of the travelling edge making the frog point 
particularly suitable for use in high speed railway switches.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
In FIG. 1, there is shown a frog designated by the reference numeral 1 and 
having a frog point 2 comprising a main point 3 and a auxiliary point 4. 
The wing rails of the frog 1 are designated by the reference numerals 5 
and 6. The wing rails 5 and 6 are fixed on sleepers 7 by means of screws 8 
in a manner to be explained later in greater detail. The foot 9 of the 
main point 3 has recesses 10 partially provided within the mounting area 
of the wing rail 5 on a sleeper 7, the purpose of said recesses being 
later explained in greater detail. 
In FIG. 2, the main point 3 is shown in its position engaging the wing rail 
5. The main point is, in this case, formed of a thick-web standard rail 
section, for example UIC 60 according to UIC 861-3V but with a web 
thickness of 30 mm or UIC 54 "profile A" according to UIC 861-2V having a 
web thickness of 28 mm. Also the asymmetric wing rail parts 5 and 6 being 
given a smaller height are adapted to the rail section used for the frog 
point, for which purpose there can, for example, be used an asymmetric 
tongue section for UIC-rail 60 kg/m according to UIC 861-2V or a "profile 
B 68.5 kg/m" according to UIC 861-2V. The wing rails 5 and 6, 
respectively, are mounted on base plates 11 having such a height that the 
total height of the base plate 11 and the added height of the wing rail 5 
or, respectively, 6 having a smaller height corresponds to the height of 
the main point 3. The wing rails 5 are fixed on the base plate 11 in a 
known manner by means of supporting members 12 being connected with the 
wing rail by a screw connection 13 and being connected with the base plate 
11 by means of a screw connection 8. The base plates 11 have at their 
front surfaces facing the point 3 recesses 14 into which can enter the 
recessed portion 10 of the rail foot 9 of the point 3 in its position 
engaging the wing rail. On account of such overlapping of the base plate 
11, any lifting movement of the point 3 is avoided and the base plate 11 
thus acts as a jack pressing down the point in its position engaging the 
wing rail. 
In the respesentation according to FIG. 3, the connection between the main 
point 3 and the auxiliary point 4 is shown in greater detail. The 
auxiliary point 4 is, like the main point 3, formed, as explained above, 
by using thick-web standard rail sections. The wing rails 5 and 6 again 
have a smaller height and show an asymmetric tongue profile and are 
mounted on the sleepers 7 with interposition of base plates 11. As can be 
seen in FIG. 3, the main point 3 and the auxiliary point 4 are connected 
by a screw connection 15, noting that the hole 16 for the screw 15 is 
designed in the auxiliary point 4 as an elongated hole extending in length 
direction of the rail section. For the purpose of admitting relative 
shifting movement between the main point and the auxiliary point, the 
screw is connected with a bushing contacting the screw head and the rail 
web of the main point for giving a connection of high strength, while the 
auxiliary point is pressed against the main point by means of spring 
elements. The hole in the main point 3 is designed as a simple bore 17. 
Like the main point, the auxiliary point 4 has a rail foot 18 for the 
purpose of giving the frog a more stable design with reduced danger to 
tilting movement. Transmission of lateral forces from the points 3 and 4 
onto the respective wing rails 5 and 6, respectively, is effected via 
supports 19 and 20 which can be fixed on the wing rail and on the frog 
point, respectively. These supports are also indicated in FIG. 1 and are 
there likewise designated by the reference numerals 19 and 20, 
respectively. 
For the purpose of providing a support between main point 3 and auxiliary 
point 4 at a great distance from the tip area, there distance members 21 
are provided, being schematically shown in FIG. 1. These distance members 
may alternately be fixed on one side of the main point and of the 
auxiliary point, so that the respective opposite engaging surface can, 
during the switching operation, slide on the thick-web standard rail 
section of the other point on account of the relative shifting movement 
between the main point and the auxiliary point. 
On account of the main points and auxiliary points being designed as 
thick-web standard rail sections, these constructional elements are 
superior in their load carrying capacity over known movable frog points. 
Furthermore, on account of using such frogs, the construction length of 
such frogs can substantially be reduced, because the relative shifting 
movement during the switching operation can be brought into the area 
between the main point and the auxiliary point, because the mechanically 
worked thick-web sections have a sufficient load carrying capacity. On 
account of using thick-web standard sections for the main point and 
auxiliary point 3 and 4, respectively, the profile shape can be continuous 
from the beginning of the point till the end of the switch, so that exact, 
predictable bending lines and shapes of a travelling edge, respectively, 
are created during a switching operation. The main point 3 and the 
auxiliary point 4 are thus continuous elastic switch components without 
rigid disturbing areas. On account of using thick-web standard rail 
sections for the main point 3 and the auxiliary point 4, it is also 
possible to give spring locations in the rail foot, such locations not 
being shown for clarity's sake, a relatively short length and to arrange 
such locations at a relatively great distance in forward direction without 
allowing the switching forces to become inadmissibly high. Such length 
reduction has furthermore a favourable influence on the total construction 
length of the frog point 2. On account of the elastic design of the 
complete frog by means of thick-web standard rail sections as points 3 and 
4 and, respectively, by means of asymmetric sections for the wing rails 5 
and 6, the frog enters the elastic behavior of the track and represents no 
foreign body within the elastic track. 
The main point 3 and the auxiliary point 4 formed of the thick-web standard 
rail section extend either until the end of the frog point 2 and are 
adapted there to the standard rail section or have their end within the 
clamped area at a distance of two to three sleeper sections in front of 
the end of the frog and are, after having been adapted to the standard 
rail section, welded with the standard rail which extends till the end of 
the frog. The wing rail portions designed as an asymmetric tongue section 
of small height within the area of the frog 1 are either forged 
immediately in front of the frog point to be adapted from the low 
asymmetric tongue profile to the standard rail section or are mutually 
adapted and welded with a standard rail extending till the begin of the 
frog. The asymmetric tongue profile may, however, also extend until the 
beginning of the frog and be only there adapted to the standard rail 
section. Furthermore, the wing rail portions either extend as an 
asymmetric tongue profile until the end of the wing rail or are forged in 
accordance to the standard rail section or mutually adapted behind the 
running-over area behind the zone behind the frog points and welded with 
the standard rail extending until the end of the wing rail. 
For the main points and the auxiliary points being formed of the thick-web 
standard rail section and for the wing rails being formed of the 
asymmetric tongue rail section of low height, there can be used either 
non-treated rail steels of natural hardness, special quality steels, 
heat-treated steels or austenitic manganese steel as rolled or cast which 
may also be pre-strengthened. In case of austenitic manganese steel, the 
adjoining standard rail, which is adjoining at the begin or at the end of 
the frog or, respectively, at the end of the wing rail, is connected to 
the respective track portion of the frog tip or, respectively, of the wing 
rail in accordance with special processes for welding austenitic manganese 
steel with rail steel. 
In place of mounting the thick-web standard rail sections in a manner shown 
in the Figures, there may also be used a type of mounting which is 
designated as inner stock rail staying. The frog points 3 and 4 can also 
be fixed within the clamped area and within the area of the wing rails 
being formed of standard rail sections by means of internally arranged 
elastic clamping plates.