FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
An interlocking system and method for controlling gates for traffic crossing at crossing junctions of railway tracks.
APPLICANT
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company -
INVENTORS
Ekram Samsul and Gawli Nilesh both of Crompton Greaves Ltd., Electronic Development centre, Global R&D Centre, Kanjurmarg (East), Mumbai - 400042, Maharashtra, India, and Siddiquee Qutbuddin & Buch Falgun both of Crompton Greaves Ltd., IPR Cell, Global R&D Centre, Kanjurmarg (East), Mumbai - 400042, Maharashtra, India; all Indian Nationals
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed.

FIELD OF THE INVENTION :
This invention relates to safety mechanisms.
Particularly, this invention relates to safety mechanisms employed at level crossings of rail networks.
Still particularly, this invention relates to an interlocking system and method for controlling gates for traffic crossing at crossing junctions of railway tracks.
BACKGROUND OF THE INVENTION:
Usually, trains accidents occur because of faults in signaling systems, ignorance of the crosser, measurement error in railway speed and the like instances. Normally, level crossing accidents are higher, especially in rural areas and areas where no manual control (of gates) for obstructing flow of traffic onto railway tracks is available.
Presently, manual signaling and relay based control is available for traffic control. Also, manual operation is required to operate the gates based on signaling system. This will lead to additional cost and reliability issues.
A new and improved safety mechanism for level crossing may reduce the disadvantages associated with conventional method and system and reduces the accident rate.

OBJECTS OF THE INVENTION:
An object of this invention is to provide an interlocking system and method which is a simple and relatively more accurate system and method for controlling the gate for traffic crossing at crossing junctions of railway tracks.
Another object of the invention is to provide an interlocking system and method for controlling gates based on a measure of distance.
Yet another object of the invention is to provide an interlocking system and method which does not require additional transmitter(s). and receiver(s) or sensor(s).
SUMMARY OF THE INVENTION :
According to this invention, there is provided an interlocking system for controlling gates for traffic crossing at crossing junctions of railway tracks, said system comprises:
a. voltage feeding means adapted to feed voltage to a portion of a
railway track spaced apart from said gate;
b. current feeding means adapted to feed current to said portion of
railway track;
c. voltage sensing means adapted to sense voltages at continuous
discrete instances of time, thereby sensing the change in voltage on
said portion of railway track;

d. current sensing means adapted to sense currents at continuous discrete
instances of time, thereby sensing the change in current on said
portion of railway track;
e. first computing means adapted to compute resistance and rate of
change of resistance on said portion of track based on said sensed
voltage, said sensed rate of change of voltage, said sensed current, and
said sensed rate of change of current;
f. second computing means adapted to compute velocity of an
approaching train with respect to sensed data at said portion of the
track, based on rate of change of resistance;
g. third computation means adapted to compute distance of train from
the gate, based on said computed speed and said computed rate of
change of resistance;
h. first storage means adapted to store a preset value of resistance and a
preset value of rate of change of resistance; i. first comparator means adapted to compare said computed resistance
with said preset resistance and said computed rate of change of
resistance with said preset rate of change of resistance; j. second storage means adapted to store preset safe distance from said
gate and preset safe velocity; k. second comparator means adapted to compare said computed distance
with said preset distance and said computed velocity with said preset
velocity; and I. controller means adapted to control actuation of said gate based on
said first comparator means and said second comparator means.

Typically, said controller means includes gate closing means adapted to close said gate if compared (computed) distance is less than safe (preset) distance.
Typically, said controller means includes gate opening means adapted to open said gate if compared (computed) distance is more than safe (preset) distance.
Typically, said system includes an alarm generation means adapted to generate an alarm during actuation of said gate.
According to this invention, there is provided an interlocking method for controlling gates for traffic crossing at crossing junctions of railway tracks, said method comprises the steps of:
a. feeding voltage to a portion of a railway track spaced apart from said
gate;
b. feeding current to said portion of railway track;
c. sensing voltages at continuous discrete instances of time, thereby
sensing the change in voltage on said portion of railway track;
d. sensing currents at continuous discrete instances of time, thereby
sensing the change in current on said portion of railway track;
e. computing resistance and rate of change of resistance on said portion
of track based on said sensed voltage, said sensed rate of change of
voltage, said sensed current, and said sensed rate of change of current;
f. computing velocity of an approaching train with respect to sensed data
at said portion of the track, based on rate of change of resistance;

g. computing distance of train from the gate, based on said computed
speed and said computed rate of change of resistance; h. storing a preset value of resistance and a preset value of rate of change
of resistance; i. comparing said computed resistance with said preset resistance and
said computed rate of change of resistance with said preset rate of
change of resistance; j. storing preset safe distance from said gate and preset safe velocity; k. comparing said computed distance with said preset distance and said
computed velocity with said preset velocity; and 1. controlling actuation of said gate based on said compared resistance,
said compared rate of change of resistance, said compared distance,
and said compared velocity.
Typically, said method includes the step of closing said gate if compared (computed) distance is less than safe (preset) distance.
Typically, said method includes the step of opening said gate if compared (computed) distance is more than safe (preset) distance.
Typically, said method includes the step of generating an alarm during actuation of said gate.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:

Figure 1 illustrates a schematic of the system; and
Figure 2 illustrates a flow diagram of the logic for said system.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to the invention there is provided a safety mechanism for level crossing at traffic crossing junctions of railway networks. According to this invention, there is provided an interlocking system and method for controlling gates for traffic crossing at crossing junctions of railway tracks.
Figure 1 illustrates a schematic of the system (100) of this invention.
In accordance with an embodiment of this invention, there is provided a voltage feeding means (VFM) adapted to feed voltage to a portion of a railway track (RT).
In accordance with another embodiment of this invention, there is provided a current feeding means (CFM) adapted to feed current to a portion of a railway track (RT).
In accordance with yet another embodiment of this invention, there is provided a voltage sensing means (VSM) adapted to sense voltages at continuous discrete instances of time, thereby sensing the change in voltage on said portion of railway track.

In accordance with still another embodiment of this invention, there is provided a current sensing means (CSM) adapted to sense currents at continuous discrete instances of time, thereby sensing the change in current on said portion of railway track.
Typically, said portion of track is spaced at a distance from the gate (G) which is to be controlled (for allowing traffic to cross over the tracks).
Typically, as load on the track increases, the current and voltage changes. The load increase (on a particular portion of the track) is due to an approaching train.
In accordance with an additional embodiment of this invention, there is provided a first computing means (FCM) adapted to compute resistance and rate of change of resistance on said portion of track based on said sensed voltage and said sensed rate of change of voltage and said sensed current and said sensed rate of change of current.
In accordance with an additional embodiment of this invention, there is provided a second computing means (SCM) adapted to compute velocity of an approaching train with respect to said portion of the track, based on rate of change of resistance which is function of voltage variation and / or current variation
As per ohms law,

V=IR, Eq. (1)
Where :
V= Voltage
I= Current
R = resistance of the path
R= V/I
By differentiation
dR/dt = (l/I)*dV/dt-V*dI/dt Eq. (la)
The above equation shows that rate of change of resistance(dR/dt) is because of voltage variation (dV/dt) and / or current variation (dI/dV).
Thus, by measuring the impact on voltage and current; the rate of change of resistance can estimated using embedded system.
Again, the resistance is
R= p*(L/A) Eq. (2)
p is the resistively of the path and L is the length of the path and A is the cross sectional area of the path
By differentiating Eq 2

dR/dt = (p/A) * dL/dt
dR/dt = (p/A) * v Eq. (2a)
Where velocity (v) = dL/dt
As per Eq. (2a) the velocity is proportional to rate of change of resistance
So, using Eq (2a) we can estimate the velocity based on rate of change of resistance which is function of voltage variation and or current variation as per Eq (1a)
In accordance with yet an additional embodiment of this invention, there is provided a third computation means (TCM) adapted to compute distance of train from the gate, based on said computed speed and said computed rate of change of resistance.
In accordance with still an additional embodiment of this invention, there is provided a first storage means (FSM) adapted to store a preset value of resistance and a preset value of rate of change of resistance.
In accordance with another additional embodiment of this invention, there is provided a first comparator means (FCM) adapted to compare said computed resistance with said preset resistance and said computed rate of change of resistance with said preset rate of change of resistance.

This provides the distance of the train and speed of the train from said gate.
In accordance with yet another additional embodiment of this invention, there is provided a second storage means (SSM) adapted to store preset safe distance from said gate and preset safe speed.
In accordance with still another additional embodiment of this invention, there is provided a second comparator means (SCM) adapted to compare said computed distance with said preset distance and said computed speed with said preset speed.
In accordance with another embodiment of this invention, there is provided a controller means (CM) adapted to control actuation of said gate based on said second comparator means. If the compared (computed) distance is less than safe (preset) distance, then closure command will close the gate.
In accordance with an additional embodiment of this invention, there is provided an alarm generation means (AGM) adapted to generate an alarm during actuation of said gate.
Figure 2 illustrates a flow diagram of the logic for said system.
Step 1: Measure the Resistance between adjacent tracks based on sensed
voltage and sensed current.
Step 2: Is that value as per preset desire value?
Step 3: Compute the rate of change of resistance

Step 4: Is the rate of change abnormal (not in limit) ?
Step 5: Compute the speed of the train by embedded controller
Step 6: Estimate the location of the train
Step 7: Is the train location and speed of the train within the safe limit of level crossing?
Step 8: If no, then controller to start motor to pull down the level crossing gate and provide signal and alarm

We claim,
1. An interlocking system for controlling gates for traffic crossing at crossing junctions of railway tracks, said system comprising:
a. voltage feeding means adapted to feed voltage to a portion of a
railway track spaced apart from said gate;
b. current feeding means adapted to feed current to said portion of
railway track;
c. voltage sensing means adapted to sense voltages at continuous
discrete instances of time, thereby sensing the change in voltage on
said portion of railway track;
d. current sensing means adapted to sense currents at continuous discrete
instances of time, thereby sensing the change in current on said
portion of railway track;
e. first computing means adapted to compute resistance and rate of
change of resistance on said portion of track based on said sensed
voltage, said sensed rate of change of voltage, said sensed current, and
said sensed rate of change of current;
f. second computing means adapted to compute velocity of an
approaching train with respect to sensed data at said portion of the
track, based on rate of change of resistance;
g. third computation means adapted to compute distance of train from
the gate, based on said computed speed and said computed rate of
change of resistance;
h. first storage means adapted to store a preset value of resistance and a preset value of rate of change of resistance;

i. first comparator means adapted to compare said computed resistance with said preset resistance and said computed rate of change of resistance with said preset rate of change of resistance;
j. second storage means adapted to store preset safe distance from said gate and preset safe velocity;
k. second comparator means adapted to compare said computed distance with said preset distance and said computed velocity with said preset velocity; and
I. controller means adapted to control actuation of said gate based on said first comparator means and said second comparator means.
2. A system as claimed in claim 1 wherein, said controller means includes gate closing means adapted to close said gate if compared (computed) distance is less than safe (preset) distance.
3. A system as claimed in claim 1 wherein, said controller means includes gate opening means adapted to open said gate if compared (computed) distance is more than safe (preset) distance.
4. A system as claimed in claim 1 wherein, said system includes an alarm generation means adapted to generate an alarm during actuation of said gate.
5. An interlocking method for controlling gates for traffic crossing at crossing junctions of railway tracks, said method comprising the steps of: a. feeding voltage to a portion of a railway track spaced apart from said
gate;

b. feeding current to said portion of railway track;
c. sensing voltages at continuous discrete instances of time, thereby
sensing the change in voltage on said portion of railway track;
d. sensing currents at continuous discrete instances of time, thereby
sensing the change in current on said portion of railway track;
e. computing resistance and rate of change of resistance on said portion
of track based on said sensed voltage, said sensed rate of change of
voltage, said sensed current, and said sensed rate of change of current;
f. computing velocity of an approaching train with respect to sensed data
at said portion of the track, based on rate of change of resistance;
g. computing distance of train from the gate, based on said computed
speed and said computed rate of change of resistance;
h. storing a preset value of resistance and a preset value of rate of change
of resistance; i. comparing said computed resistance with said preset resistance and
said computed rate of change of resistance with said preset rate of
change of resistance; j. storing preset safe distance from said gate and preset safe velocity; k. comparing said computed distance with said preset distance and said
computed velocity with said preset velocity; and I. controlling actuation of said gate based on said compared resistance,
said compared rate of change of resistance, said compared distance,
and said compared velocity.
6. An interlocking method as claimed in claim 1 wherein, said method includes the step of closing said gate if compared (computed) distance is less than safe (preset) distance.

7. An interlocking method as claimed in claim 1 wherein, said method includes the step of opening said gate if compared (computed) distance is more than safe (preset) distance.
8. An interlocking method as claimed in claim 1 wherein, said method includes the step of generating an alarm during actuation of said gate.