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 rail tracks by measuring track resistance and rate of change of resistance to prevent train collision.
APPLICANT
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTORS
Samsul Ekram & Nilesh Gawli both of Crompton Greaves Ltd., Electronic Development centre, Global R&D Centre, Kanjurmarg (East), Mumbai -400042, Maharashtra, India and Qutbuddin Siddiquee & Falgun Buch 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 the field of electronics and safety mechanisms.
Particularly, this invention relates to an interlocking system and method for rail tracks by measuring track resistance and rate of change of resistance to prevent train collision.
BACKGROUND OF THE INVENTION:
Usually trains accidents occur due to faults in signaling systems, ignorance of the signal operator or train driver, measurement error in between railways and many such problems. Presently, manual signaling and relay based control is available for traffic control. Conventionally, position of the vehicle is being measured by putting optical sensor and also by using reflection light.
If any obstacle comes between the light transmitter and light receiver, then signal will be weak and result in accidents. Also, in bad whether conditions, possibility of failure of such devices are a major concern.
There is a need for an interlocking system and method which eliminates the disadvantages associated with conventional system and reduces the accident rate.

OBJECTS OF THE INVENTION :
An object of the invention is to provide an interlocking system and method for rail tracks to prevent train collision which is simple and more accurate.
Another object of the invention is to provide an interlocking system which measures the distance between two trains and prevents accidents.
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 rail tracks by measuring track resistance and rate of change of resistance to prevent train collision, said system comprises:
a. voltage feeding means adapted to feed voltage to said railway track;
b. current feeding means adapted to feed current to said railway track;
c. voltage sensing means adapted to sense voltages whenever a load is
sensed on a portion of the track, thereby sensing the change in voltage
on said portion of loaded railway track;
d. current sensing means adapted to sense currents whenever a load is
sensed on a portion of the track, 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 a first 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 first portion of
the track, based on rate of change of resistance;
g. third computing means adapted to compute resistance and rate of
change of resistance on a second 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;
h. fourth computing means adapted to compute velocity of an approaching train with respect to sensed data at said second portion of the track, based on rate of change of resistance;
i. fifth computation means adapted to compute distance of first train at said first position from second train at said second position, based on said computed speed and said computed rate of change of resistance;
j. first storage means adapted to store a preset value of resistance and a preset value of rate of change of resistance;
k. 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;
1. second storage means adapted to store preset safe distance between two adjacent trains and preset safe velocity of a first train with respect to a second adjacent train;

m. second comparator means adapted to compare said computed distance with said preset distance and said computed velocity with said preset velocity; and
n. controller means adapted to control actuation of said signals based on said second comparator means.
Typically, said controller means includes means to turn the adjacent signals with respect to said second train if compared (computed) distance is less than safe (preset) distance.
Typically, said controller means includes means to turn the adjacent signals green with respect to said second train if compared (computed) distance is more than safe (preset) distance.
According to this invention, there is provided an interlocking method for rail tracks by measuring track resistance and rate of change of resistance to prevent train collision s, said method comprising the steps of:
a. feeding voltage to said railway track;
b. feeding current to said railway track;
c. sensing voltages whenever a load is sensed on a portion of the track,
thereby sensing the change in voltage on said portion of loaded
railway track;
d. sensing currents whenever a load is sensed on a portion of the track,
thereby sensing the change in current on said portion of railway track;
e. computing resistance and rate of change of resistance on a first
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 first portion of the track, based on rate of change of resistance;
g. computing resistance and rate of change of resistance on a second
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;
h. computing velocity of an approaching train with respect to sensed data
at said second portion of the track, based on rate of change of
resistance; i. computing distance of first train at said first position from second
train at said second position, based on said computed speed and said
computed rate of change of resistance; j. storing a preset value of resistance and a preset value of rate of change
of resistance; k. comparing said computed resistance with said preset resistance and
said computed rate of change of resistance with said preset rate of
change of resistance; 1. storing preset safe distance between two adjacent trains and preset
safe velocity of a first train with respect to a second adjacent train; m. comparing said computed distance with said preset distance and said
computed velocity with said preset velocity; and n. controlling actuation of said signals based on said second comparator
means.

Typically, said method includes the step of turning the adjacent signals with respect to said second train, red, if compared (computed) distance is less than safe (preset) distance.
Typically, said method includes the step of turning the adjacent signals with respect to said second train, green, if compared (computed) distance is more than safe (preset) distance.
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 an interlocking system and method for rail tracks by measuring track resistance and rate of change of resistance to prevent train collision.
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 said railway track (RT).
In accordance with another embodiment of this invention, there is provided a current feeding means (CFM) adapted to feed current to said railway track (RT).
In accordance with yet another embodiment of this invention, there is provided a voltage sensing means (VSM) adapted to sense voltages whenever a load is sensed on a portion of the track, thereby sensing the change in voltage on said portion of loaded railway track. Typically, when a train passes over the track, the voltage sensing means senses the change in voltage due to load.
In accordance with still another embodiment of this invention, there is provided a current sensing means (CSM) adapted to sense currents whenever a load is sensed on a portion of the track, thereby sensing the change in current on said portion of loaded railway track. Typically, when a train passes over the track, the voltage sensing means senses the change in current due to load.
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 a first 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 first portion of the track, based on rate of change of resistance which is function of voltage variation and / or current variation
In accordance with an additional embodiment of this invention, there is provided a third computing means (TCM) adapted to compute resistance and rate of change of resistance on a second 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 fourth computing means (FRCM) adapted to compute velocity of an approaching train with respect to said second portion of the track, based on rate of change of resistance which is function of voltage variation and / or current variation.
Typically, said first portion and said second portion are adjacent portions based on pre-defined distance parameters.
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) 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 (la)
In accordance with yet an additional embodiment of this invention, there is provided a fifth computation means (FFCM) adapted to compute distance of first train at said first position from second train at said second position, 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 (FCPM) 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 relative speed of first train with respect to second train. The trains may be on the same path headed towards

each other (in cases of envisaged collision) or one travelling at a greater speed than another and headed towards the another on the same path (in cases of envisaged collision).
In accordance with yet another additional embodiment of this invention, there is provided a second storage means (SSM) adapted to store preset safe distance between two adjacent trains and preset safe velocity of a first train with respect to a second adjacent train.
In accordance with still another additional embodiment of this invention, there is provided a second comparator means (SCPM) adapted to compare said computed distance with said preset distance and said computed velocity with said preset velocity.
In accordance with another embodiment of this invention, there is provided a controller means (CM) adapted to control actuation of signals (SG) based on said second comparator means. If the compared (computed) distance is less than safe (preset) distance, then red signals will be actuated and the driver / guard of the both trains will be informed.
The computational means will be referred to as an embedded controller for the purposes of explanation of the flow diagram.
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: Estimate the distance between two trains by embedded controller.
Step 4: Calculate the rate of change of resistance.
Step 5: Estimate the rate of change of resistance value by embedded controller.
Step 6: Is the rate of change of resistance increasing?
Step 7: If no, estimate the relative speed of both the trains by embedded controller.
Step 8: Is the distance between both train and speed of the trains within the safe limit for non-collision?
Step 9: Give Signal - Give Red Signal to all nearest signals, parallely inform Driver and Guard through signal and interlock the train as per red signal.

We claim,
1. An interlocking system for rail tracks by measuring track resistance and rate of change of resistance to prevent train collision, said system comprising:
a. voltage feeding means adapted to feed voltage to said railway track;
b. current feeding means adapted to feed current to said railway track;
c. voltage sensing means adapted to sense voltages whenever a load is
sensed on a portion of the track, thereby sensing the change in voltage
on said portion of loaded railway track;
d. current sensing means adapted to sense currents whenever a load is
sensed on a portion of the track, 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 a first 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 first portion of
the track, based on rate of change of resistance;
g. third computing means adapted to compute resistance and rate of
change of resistance on a second 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;
h. fourth computing means adapted to compute velocity of an approaching train with respect to sensed data at said second portion of the track, based on rate of change of resistance;

i. fifth computation means adapted to compute distance of first train at
said first position from second train at said second position, based on
said computed speed and said computed rate of change of resistance; j. first storage means adapted to store a preset value of resistance and a
preset value of rate of change of resistance; k. 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; 1. second storage means adapted to store preset safe distance between
two adjacent trains and preset safe velocity of a first train with respect
to a second adjacent train; m. second comparator means adapted to compare said computed distance
with said preset distance and said computed velocity with said preset
velocity; and n. controller means adapted to control actuation of said signals based on
said second comparator means.
2. A system as claimed in claim 1 wherein, said controller means includes means to turn the adjacent signals with respect to said second train if compared (computed) distance is less than safe (preset) distance.
3. A system as claimed in claim 1 wherein, said controller means includes means to turn the adjacent signals green with respect to said second train if compared (computed) distance is more than safe (preset) distance.

4. An interlocking method for controlling gates for rail tracks by measuring track resistance and rate of change of resistance to prevent train collision, said method comprising the steps of:
a. feeding voltage to said railway track;
b. feeding current to said railway track;
c. sensing voltages whenever a load is sensed on a portion of the track,
thereby sensing the change in voltage on said portion of loaded
railway track;
d. sensing currents whenever a load is sensed on a portion of the track,
thereby sensing the change in current on said portion of railway track;
e. computing resistance and rate of change of resistance on a first
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 first portion of the track, based on rate of change of resistance;
g. computing resistance and rate of change of resistance on a second
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;
h. computing velocity of an approaching train with respect to sensed data
at said second portion of the track, based on rate of change of
resistance; i. computing distance of first train at said first position from second
train at said second position, based on said computed speed and said
computed rate of change of resistance;

j. storing a preset value of resistance and a preset value of rate of change
of resistance; k. comparing said computed resistance with said preset resistance and
said computed rate of change of resistance with said preset rate of
change of resistance; 1. storing preset safe distance between two adjacent trains and preset
safe velocity of a first train with respect to a second adjacent train; m. comparing said computed distance with said preset distance and said
computed velocity with said preset velocity; and n. controlling actuation of said signals based on said second comparator
means.
5. An interlocking method as claimed in claim 1 wherein, said method includes the step of turning the adjacent signals with respect to said second train, red, if compared (computed) distance is less than safe (preset) distance.
6. An interlocking method as claimed in claim 1 wherein, said method includes the step of turning the adjacent signals with respect to said second train, green, if compared (computed) distance is more than safe (preset) distance.