TECHNICAL FIELD
[001] The present disclosure relates in general to locomotives. More particularly, the present
disclosure relates to a circuit for controlling lights in a locomotive.
BACKGROUND
[002] A legacy railroad locomotive supplies motive power to control a railroad car. Generally,
the locomotive is operated by control operators throughout the day. The locomotive comprises
electricals including various lights such as cabin lights, panel lights, and the like which are
powered via a battery of the locomotive. When the locomotive is operated, the battery is
charged by a power source (generally by an engine). However, when the locomotive is turned
OFF, the lights are powered by the battery and the battery gets discharged continuously. There
may be situations where a control operator forgets to turn OFF the lights of the locomotive
when the locomotive is not operated. In such instances the light draws power from the battery
while the battery is discharged continuously. Eventually, the lights turn OFF when the battery
is completely discharged. In such situations, when there is a requirement to turn ON the lights,
the control operator may not be able to switch ON the lights as the battery is completely
discharged. Hence, there is a need of a circuit to overcome the above-mentioned problems.
[003] The information disclosed in this background of the disclosure section is only for
enhancement of understanding of the general background of the invention and should not be
taken as an acknowledgement or any form of suggestion that this information forms the prior
art already known to a person skilled in the art.
SUMMARY
[004] In an embodiment, the present disclosure discloses a circuit for controlling lights in a
locomotive. The circuit comprises a first relay configured to be operated based on a state of a
knife switch. The knife switch connects a battery of the locomotive to a power source of the
locomotive. Further, the circuit comprises a timer connected to the first relay. The timer is
configured to generate a signal after a predefined time, when the first relay is in an OPEN state.
Furthermore, the circuit comprises a second relay connected to one or more lights in the
locomotive. The second relay is configured to be in an OPEN state, when the signal is received
from the timer. The one or more lights are switched OFF when the second relay in the OPEN
state.

[005] The foregoing summary is illustrative only and is not intended to be in any way limiting.
In addition to the illustrative aspects, embodiments, and features described above, further
aspects, embodiments, and features will become apparent by reference to the drawings and the
following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[006] The novel features and characteristic of the disclosure are set forth in the appended
claims. The disclosure itself, however, as well as a preferred mode of use, further objectives
and advantages thereof, will best be understood by reference to the following detailed
description of an illustrative embodiment when read in conjunction with the accompanying
figures. One or more embodiments are now described, by way of example only, with reference
to the accompanying figures wherein like reference numerals represent like elements and in
which:
[007] Figure 1A shows a schematic of existing electrical circuit for controlling lights in a
locomotive;
[008] Figure 1B shows a schematic illustrating discharging of a battery in existing electrical
circuit for controlling lights in a locomotive;
[009] Figure 2 shows an exemplary circuit for controlling lights in a locomotive, during
operation of the locomotive, in accordance with some embodiments of the present disclosure;
[0010] Figure 3 shows an exemplary state of a circuit for controlling lights of a locomotive, in
accordance with some embodiments of the present disclosure; and
[0011] It should be appreciated by those skilled in the art that any block diagrams herein
represent conceptual views of illustrative systems embodying the principles of the present
subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams, state
transition diagrams, pseudo code, and the like represent various processes which may be
substantially represented in computer readable medium and executed by a computer or
processor, whether or not such computer or processor is explicitly shown.
DETAILED DESCRIPTION
[0012] In the present document, the word "exemplary" is used herein to mean "serving as an
example, instance, or illustration." Any embodiment or implementation of the present subject

matter described herein as "exemplary" is not necessarily to be construed as preferred or
advantageous over other embodiments.
[0013] While the disclosure is susceptible to various modifications and alternative forms,
specific embodiment thereof has been shown by way of example in the drawings and will be
described in detail below. It should be understood, however that it is not intended to limit the
disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all
modifications, equivalents, and alternative falling within the scope of the disclosure.
[0014] The terms “comprises”, “comprising”, or any other variations thereof, are intended to
cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of
components or steps does not include only those components or steps but may include other
components or steps not expressly listed or inherent to such setup or device or method. In other
words, one or more elements in a system or apparatus proceeded by “comprises… a” does not,
without more constraints, preclude the existence of other elements or additional elements in
the system or apparatus.
[0015] Figure 1A shows a schematic of existing electrical circuit for controlling lights in a
locomotive. The electrical circuit comprises a knife switch 102 connecting a power source 101
to the battery 103. The battery powers one or more lights 104 of the locomotive. When the
operator switches the knife switch 102 from a CLOSED state to an OPEN STATE and the one
or more lights 104 are in an ON state, the battery 103 may start to discharge as shown in Figure
1B. Eventually, the one or more lights 104 may be turned OFF when the battery 103 is
completely discharged. In such situation, when there is a requirement to turn ON the one or
more lights 104 (e.g., when another control operator operates the locomotive at night-time),
the control operator may not be able to switch ON the one or more lights 104 as the battery is
completely discharged and it takes time for the battery 103 to be charged after the knife switch
102 is switched to the CLOSED state. The knife switch 102 is manually operated to recharge
the battery 103 and switch ON the one or more lights 104. The knife switch 102 may be located
inside the locomotive. The control operator may face difficulty to reach to the knife switch 102,
especially when cabin light is in an OFF state.
[0016] Embodiments of the present disclosure relate to a circuit for controlling the one or more
lights 104 in the locomotive. In the locomotive, the knife switch 102 connects the battery 103
and the power source 101 of the locomotive. A first relay is operated based on a state of the

knife switch 102. A timer is connected to the first relay. The timer generates a signal after a
predefined time, when the first relay is in an OPEN state. A second relay is connected to the
one or more lights 104 in the locomotive. The second relay is configured to be in an OPEN
state, when the signal is received from the timer. When the second relay is in the OPEN state,
the one or more lights 104 of the locomotive are switched OFF. In the present disclosure, the
one or more lights 104 are controlled to automatically switch OFF when the knife switch 102
connecting the battery 103 and the power source 101 is disabled. Hence, when the control
operator forgets to switch OFF the one or more lights 104 of the locomotive and has
disconnected the power source 101 to the battery 103, the circuit automatically switches OFF
the one or more lights 104.
[0017] Figure 2 shows an exemplary circuit 200 for controlling lights in a locomotive, during
operation of the locomotive. The circuit 200 comprises a knife switch 102, a battery 103, one
or more lights 2011 and 2012, one or more light switches 2021 and 2022, a first relay 203, a
second relay 204, a timer 205, other components 206, and a maintenance switch 207. The
maintenance switch 207 may be a bypass switch to provide a continuous power supply in the
event of maintenance or repair. The knife switch 102 is used to power the battery 103 from the
power supply (shown in Figure 1A and Figure 1B). The battery 103 powers various
components in the locomotive. For example, the battery 103 powers the one or more lights
2011 and 2012 of the locomotive. The one or more lights 2011 and 2012 may be cabin lights,
panel lights, head lights, flasher lights, and the like. In the present disclosure, 2011 represents
cabin light and 2012 represents panel light, for descriptive purposes only and should not be
considered as a limitation. The one or more lights 2011 and 2012 is also referred as the one or
more lights 201 hereafter in the present description. The one or more light switches 2021 and
2022 are configured to operate the one or more lights 2011 and 2012, respectively. The one or
more lights switches 2021 and 2022 may be a two-way switch, a three-way switch, and the like.
The one or more lights switches 2021 and 2022 are also referred as the one or more lights
switches 202 hereafters in the present description.
[0018] The circuit 200 comprises the first relay 203. The first relay 203 which is represented
twice in Figure 2 indicates the same component. Due to various circuit components, the first
relay 203 is represented twice for convenience sake only, and should not be understood
otherwise. The first relay 203 may be configured to be operated based on a state of the knife
switch 102. In an embodiment, the first relay 203 may be configured in a normally CLOSED

state during operation of the locomotive when the knife switch 102 is in a CLOSED state. The
CLOSED state of the first relay 203 is represented as two parallel lines in Figure 2. The circuit
200 comprises the timer 205. The timer 205 is device which counts to a predefined time. In an
embodiment, the timer 205 may be a down timer or an up timer. The timer 205 switches an
equipment ON/OFF after the predefined time. The timer 205 may have two states, a SET state,
and a RESET state. The SET state may begin a clock and count to the predefined time (i.e., the
timer 205 is ON and begins to count until the predefined time is reached when SET). The
RESET state may correspond to resetting the clock to 0 (i.e., the timer 205 is OFF after counting
until the predefined time). In an embodiment, the above action of the timer 205 may be reversed
as well. For example, the timer 205 may provide a HIGH signal during SET state. In another
example, the timer 205 may provide a LOW signal during the set STATE. During operation of
the locomotive, the timer 205 may be in the RESET state. The RESET state of the timer 205 is
shown as a shaded region in Figure 2. The second relay 204 is connected to one or more lights
201 in the locomotive. In an embodiment, the second relay 204 may be configured as a
normally CLOSED relay during operation of the locomotive. The one or more light switches
202 are connected in series with the second relay 204.
[0019] In an embodiment, the circuit 200 may comprise the timer 205 and the second relay 204
as separate components. The second relay 204 may be connected to the timer 205. In another
embodiment, the circuit 200 may comprise a timer relay (a single unit) comprising the timer
205 and the second relay 204. The other components 206 may comprise control brake units,
electronic controls, and the like. Consider an example where a control operator of the
locomotive has forgot to switch OFF the one or more lights 201 in the locomotive. This instance
is illustrated in Figure 1A which shows the one or more lights 201 as shaded regions to illustrate
the one or more lights 201 in a ON state. Also, the control operator may have switched the
knife switch 102 to the OPEN state. Figure 1A illustrates the knife switch 102 in the OPEN
state.
[0020] Figure 3 shows an exemplary state of the circuit 200 for controlling the one or more
lights 201 of the locomotive. The one or more lights 201 are controlled when the knife switch
102 is the OPEN state and the one or more lights 201 are in the ON state. The knife switch 102
may provide a first control signal to the first relay 203, when the knife switch 102 is in the
OPEN state. That is, the first relay 203 may continue to be in the CLOSED state while receiving
power via the knife switch 102. The first relay 203 switches from the normally CLOSED state

to the OPEN state, upon receiving the first control signal (when the power is not received via
the knife switch 102). The OPEN state of the first relay 203 is shown as two parallel lines with
a cross line in Figure 3. The first relay 203 may provide a second control signal to the timer
205 to activate the timer 205. Like the first relay 203, the timer 205 may continue to be in the
RESET state while receiving power via the first relay 203. The timer 205 may switch to the
SET state, upon receiving the second control signal (when the power is not received via the
first relay 203). The SET state of the timer 205 is shown as shaded region in Figure 3. The
timer 205 may start counting down the predefined time in the SET state. The predefined time
may be 5 mins, i.e., the timer 205 is configured to RESET state after 5 mins from the SET state.
The timer 205 may be configured to generate a signal after the predefined time and the second
relay 204 may receive the signal from the timer 205. The second relay 204 may switch from
the normally CLOSED state to the OPEN state, upon receiving the signal from the timer 205.
The second relay 204 may be connected to the one or more lights 201 in the locomotive. The
second relay 204 connects the one or more lights 201 to the battery 103 via the one or more
light switches 202. When the second relay 204 is in the OPEN state, the one or more light
switches 202 is in the OPEN state. Hence, there is an open circuit between the battery 103 and
the one or more lights 201. Hence, the one or more lights 201 are switched to the OFF state. A
person skilled in the art will appreciate that any other configurations of the components such
as the knife switch 102, the first relay 203, the second relay 204, and the timer 205 may be
used, such that the components control the one or more lights 201 in the locomotive.
[0021] By way of the circuit 200 provided in the present disclosure, the one or more lights 201
of the locomotive are automatically switched to the OFF state. Further, discharging of the
battery 103 of the locomotive is avoided. Hence, power of the locomotive is saved.
[0022] The terms "an embodiment", "embodiment", "embodiments", "the embodiment", "the
embodiments", "one or more embodiments", "some embodiments", and "one embodiment"
mean "one or more (but not all) embodiments of the invention(s)" unless expressly specified
otherwise.
[0023] The terms "including", "comprising", “having” and variations thereof mean "including
but not limited to", unless expressly specified otherwise.

[0024] The enumerated listing of items does not imply that any or all of the items are mutually
exclusive, unless expressly specified otherwise. The terms "a", "an" and "the" mean "one or
more", unless expressly specified otherwise.
[0025] A description of an embodiment with several components in communication with each
other does not imply that all such components are required. On the contrary a variety of optional
components are described to illustrate the wide variety of possible embodiments of the
invention.
[0026] When a single device or article is described herein, it will be readily apparent that more
than one device/article (whether or not they cooperate) may be used in place of a single
device/article. Similarly, where more than one device or article is described herein (whether or
not they cooperate), it will be readily apparent that a single device/article may be used in place
of the more than one device or article or a different number of devices/articles may be used
instead of the shown number of devices or programs. The functionality and/or the features of
a device may be alternatively embodied by one or more other devices which are not explicitly
described as having such functionality/features. Thus, other embodiments of the invention need
not include the device itself.
[0027] Finally, the language used in the specification has been principally selected for
readability and instructional purposes, and it may not have been selected to delineate or
circumscribe the inventive subject matter. It is therefore intended that the scope of the invention
be limited not by this detailed description, but rather by any claims that issue on an application
based here on. Accordingly, the disclosure of the embodiments of the invention is intended to
be illustrative, but not limiting, of the scope of the invention, which is set forth in the following
claims.
[0028] While various aspects and embodiments have been disclosed herein, other aspects and
embodiments will be apparent to those skilled in the art. The various aspects and embodiments
disclosed herein are for purposes of illustration and are not intended to be limiting, with the
true scope being indicated by the following claims.
Referral Number Description
101 Power source

102 Knife switch
103 Battery
104 Light
200 Circuit
2011, 2012 One or more lights
2021, 2022 One or more light switches
203 First relay
204 Second relay
205 Timer
206 Other components
207 Maintenance Switch

We claim:
1. A circuit (200) for controlling lights (201) in a locomotive, the circuit (200) comprising:
a first relay (203) configured to be operated based on a state of a knife switch (102)
connecting a battery (103) of the locomotive to a power source (101) of the locomotive;
a timer (205) connected to the first relay (203), configured to generate a signal after a
predefined time, when the first relay (203) is in an OPEN state; and
a second relay (204) connected to one or more lights (201) in the locomotive,
configured to be in an OPEN state, when the signal is received from the timer (205), thereby
switching OFF the one or more lights (201).
2. The circuit (200) as claimed in claim 1, wherein the state of the knife switch (102) is one of,
an OPEN state and a CLOSED state.
3. The circuit (200) as claimed in claim 1, wherein the one or more lights (201) are in a ON state.
4. The circuit (200) as claimed in claim 1, further comprises one or more light switches (202),
connected in series with the second relay (204), configured to operate the one or more lights
(201).
5. The circuit (200) as claimed in claim 1, wherein the first relay (203) is normally in a CLOSED
state.
6. The circuit (200) as claimed in claim 1, wherein the second relay (204) is normally in a
CLOSED state.