Hi!I am Manisha i would like to get details on circuit diagram of railway accident avoiding system.

The Indian Railways has the world's fourth largest railway
network in the world, after that of the United States,
Russia and China [3]. The railways traverse the length and
breadth of the country and carry over 20 million
passengers and 2 million tons of freight daily. It is one of
the world's largest commercial or utility employers, with
more than 1.6 million employees. About 15000 trains
work every day. Unfortunately there have been many
accidents involved in the railways.
The Railways has the most intricate and involved interdependencies.
Safety on the Railways is the end product of
the cohesive fusion of its myriad parts. A single flaw in
the 64,600 route kms of track that criss-cross the country,
a defect in over 9,500 locos, 55,000 coaches and 2.39
lakhs wagons that haul about 23 million passengers and
nearly 2.7 million tons of freight every day, an incorrect
indication on one of the thousands of signals that dot the
rail landscape, a mistake or an act of negligence by one of
its staff directly associated with train running, even a rash
act by one of the millions of road users who daily
negotiate around odd level crossing gates spread across the
system, an irresponsible act of carrying inflammable
goods – any one of these multiple possibilities has the
potential to cause a major tragedy. Added to these are the
acts of sabotage by misguided elements spanning the
whole country, Thus utmost vigil is safety in operations
and also security of the traveling public.
II. VARIOUS IMPORTANT COMPONENTS OF ADVANCED
RAILWAYS ACCIDENT PREVENTION SYSTEM
Some of the major components utilized in this system are
microcontrollers, IR sensors and zigbee.
A. AT89S52 Microcontroller
The AT89S52 is a low-power, high-performance CMOS
8-bit microcontroller with 8K bytes of in-system
programmable Flash memory. The device is manufactured
using Atmel‟s high-density nonvolatile memory
technology and is compatible with the industry-standard
80C51 instruction set and pinout. The AT89S52 provides
the following standard features: 8K bytes of Flash, 256
bytes of RAM, 32 I/O lines, Watchdog timer, two data
pointers, three 16-bit timer/counters, a six-vector two-level
interrupt architecture, a full duplex serial port, on-chip
oscillator, and clock circuitry. 32 I/O lines can be used to
output data and order other devices to do certain work, or
to read the state of a sensor, or a switch. Most of the ports
of the 89S52 have „dual function meaning that they can be
used for two different functions.
B. IR Sensors
An infrared sensor is an electronic instrument that is used
to sense certain characteristics of its surroundings by
either emitting and/or detecting infrared radiation. It is
also capable of measuring heat of an object and detecting
motion. Infrared waves are not visible to the human eye.
A typical system for detecting infrared radiation using
infrared sensors includes the infrared source such as
blackbody radiators, tungsten lamps, and silicon carbide.
In case of active IR sensors, the sources are infrared lasers
and LEDs of specific IR wavelengths. Next is the
transmission medium used for infrared transmission,
which includes vacuum, the atmosphere, optical fibers.
Finally, the infrared detector completes the system for
detecting infrared radiation. The output from the detector
is usually very small, hence pre amplifiers coupled with
circuitry are added to further process the received signals.