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THE SWITCHES
MARCH 2015
Research, Planning & Coordination Department
THE SWITCHES
DESCRIPTION
ELEMENTS OF THE SWITCHES
GEOMETRIES AND PROPERTIES OF THE SWITCHES
ALLOWABLE MAXIMUM SPEED ON SWITCHES
MARCH 2015
Research, Planning & Coordination Department
THE SWITCHES
DESCRIPTION
Description
Switches are designed to steer trains safely from one track to
another.
Switches are complex components of railway lines. They need
frequent inspection and maintenance. The typical service lives of
switches are given below:
Wooden-sleeper switches: 20 years
Concrete-sleeper switches: 30 years
Rails used for switches are R260 (900A), 350 HT or of similar
stiffness
For RL (Rapid Lines) and HSL (High Speed Lines) lines (lines where
V160km/h), frog turnouts are used. For conventional lines (lines
where V<160 km/h), frog turnouts or fixed frog turnouts are used
The maximum speed allowed over fixed frog turnouts is 160
km/h.
MARCH 2015
Research, Planning & Coordination Department
THE SWITCHES
DESCRIPTION
Figure : Switch and its components
MARCH 2015
Research, Planning & Coordination Department
THE SWITCHES
DESCRIPTION
Figure : Simple switch
Figure : Crossover
MARCH 2015
Research, Planning & Coordination Department
THE SWITCHES
DESCRIPTION
Figure : Diamond crossing
Figre : Double crossover
MARCH 2015
Research, Planning & Coordination Department
THE SWITCHES
DESCRIPTION
MARCH 2015
Research, Planning & Coordination Department
THE SWITCHES
ELEMENTS OF THE SWITCHES
Elements of switches
Switch panel:
Switch panel starts with swith toes and ends with switch
heels. Switch rails must be very close to stock rails because
wheels must be directed without any damage. Thefore they
end with a pointy end and their tip holds into lower level of
the rail head of the stock rail. Switch panels opening distance
is 15 16 cm.
Figure : Contact between stock rail and closure rails
MARCH 2015
Research, Planning & Coordination Department
THE SWITCHES
ELEMENTS OF THE SWITCHES
Closure panel :
Two middle rails crosses on the closure panel. Its function is to
prevent possible damage to the wheels.
Wing rails :
Wing rails provides wheels pass through crossing panel and weak
switch tips.
Hydraulic switch box:
Switches that works as a line connecter getting heavier and longer
each passing year. As a result of this a lot of locking, organizing
and check systems must be connected to each. Traditional way to
connect these systems to use a hand operated switch levers. Hand
operated switch levers requires a lot of time and has high
financial difficulties. Hydraulic switch box uses engine power to
organize switches. When compare to traditional system it needs
smaller place to assemble, its lighter, and has less parts to
assemble. These make it easier to assemble and maintenance.
MARCH 2015
Research, Planning & Coordination Department
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THE SWITCHES
ELEMENTS OF THE SWITCHES
Check rails: To prevent wheel flange to hit crossing panels tip
check rails must be placed at right across to crossing nose. They
work as a directing rails.
The other elements are switch lockes, switch heaters and switch
identification systems.
MARCH 2015
Research, Planning & Coordination Department
11
THE SWITCHES
ELEMENTS OF THE SWITCHES
Geometries and properties of the switches
Schematic drawing of a simple switch is shown in figure below.
MARCH 2015
Research, Planning & Coordination Department
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MARCH 2015
THE SWITCHES
ELEMENTS OF THE SWITCHES
WA start of the switch
WE end of the switch
WP angle point
switch angle
Tg 1:n (switch slope)
R
radius of the switch curve
T
tangent of the switch curve
L
length of the switch curve
Sp length between main track and the branch track at the
end of the switch
Curve of the switch
Only a few curve is able in railways. The reason for this is
structural and planning causes. Most of the European
railways use the data shown in figure below.
Research, Planning & Coordination Department
13
THE SWITCHES
ELEMENTS OF THE SWITCHES
Description
Radius [m]
Curve[1:n]
Geometric
length[m]
v [km/s]
EW 190 -1:7
190
1:7
27.01
40
EW 190 -1:7,5
190
1:7,5
25.86
40
EW 190 -1:9
190
1:9
27.14
40
EW 300 -1:9
300
1:9
33.23
50
EW 300 -1:14
300
1:14
35.23
50
EW 500 -1:12
500
1:12
41.49
60
EW 500 -1:14
500
1:14
42.37
60
EW 760 -1:14
760
1:14
54.22
80
EW 760 -1:18,5
760
1:18,5
52.93
80
EW 1200 -1:18,5
1200
1:18,5
64.82
100
EW 2500 -1:26,5
2500
1:26,5
94.00
130
EW 4000 -1:33,5
4000
1:33,5
160
EW 7000 /60001:42
6000
7000
1:42
200
MARCH 2015
Research, Planning & Coordination Department
14
THE SWITCHES
ELEMENTS OF THE SWITCHES
Allowable maximum speeds over switches
The maximum speed over the straight track of a switch depends
on the switch design.
The maximum speed allowed over the straight track of a fixed
frog turnout is 160 km/h.
The maximum speed over the diverted track of a switch
depends on the radius of the diverted track. Maximum speeds
over diverted tracks of switches are given in Table -1.
MARCH 2015
Research, Planning & Coordination Department
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THE SWITCHES
ELEMENTS OF THE SWITCHES
Curve Radius of Diverging
Track
MARCH 2015
Maximum speed
over diverted track
[m]
[km/h]
190
300
500
760
1200
1500
2500
3000
3550
6000, 7000
30
40
65
80
100
110
130
160
170
200
Turnout angle
(Tg )
1:7, 1:7.5, 1:9
1:9, 1:14
1:12, 1:14
1:14, 1:18.5
1:18.5
1:23.8
1:26.5
1:29
1:46
1:42
Research, Planning & Coordination Department
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