this is notes of metro system and engineering as per PTU

1. Metro system and
engineering
MECHANICAL SYSTEMS
SHUBHAM SHARMA
Department of civil engineering
BGIET, SANGRUR

2. NEED FOR VENTILATION AND AIR CONDITIONING
 The underground stations of the Metro Corridor are built in a confined space. A large number
of passengers occupy concourse halls and the platforms, especially at the peak hours. The
platform and concourse areas have a limited access from outside and do not have natural
ventilation. It is therefore, essential to provide forced ventilation in the stations and inside the
tunnel for the purpose of:
1. Supplying fresh air for the physiological needs of passengers and the authority’s staff;
2. Removing body heat, obnoxious odours and harmful gases like carbon dioxide exhaled
during breathing;
3. Preventing concentration of moisture generated by body sweat and seepage of water in
the sub-way;
4. Removing large quantity of heat dissipated by the train equipment like traction motors,
braking units, compressors mounted below the under-frame, lights and fans inside the
coaches, A/c units etc.;
5. Removing vapour and fumes from the battery and heat emitted by light fittings, water
coolers, Escalators, Fare Gates etc. working in the stations;
6. Removing heat from air conditioning plant and sub-station and other equipment, if

3.  This large quantity of heat generated in M.R.T. underground stations cannot be extracted
by simple ventilation, especially when the outdoor air temperature and humidity is high.
It is, therefore, essential to provide mechanical cooling in order to remove the heat to
the maximum possible extent. As the passengers stay in the stations only for short
periods, a fair degree of comfort conditions are considered appropriate. In winter
months it may not be necessary to cool the ventilating air as the heat generated within
the station premises would be sufficient to maintain the comfort requirement.

4. ventilation system
 The ventilation system in metro systems plays a crucial role in maintaining a comfortable and
safe environment for passengers and staff. It helps ensure proper air circulation, remove
pollutants, and control temperature and humidity levels within the metro tunnels and stations.
 Metro ventilation systems typically consist of a combination of supply and exhaust fans
strategically placed throughout the system. The supply fans bring in fresh air from outside, while
the exhaust fans remove stale air and pollutants.
 This continuous exchange of air helps maintain good air quality and prevents the buildup of
harmful substances. To further enhance air quality, some metro systems incorporate air filtration
systems. These filters help remove particulate matter, dust, and other pollutants, ensuring
cleaner air for passengers to breathe. The ventilation system also plays a critical role in
controlling temperature and humidity. It helps regulate the climate within the metro tunnels and
stations, ensuring a comfortable environment for passengers regardless of the weather
conditions outside. Overall, the ventilation system in metro systems is designed to provide a
pleasant and healthy experience for passengers by ensuring proper air circulation, pollutant
removal, and climate control.

5.  The ventilation system in metro systems controls air quality through a combination of
mechanisms. First, it helps in the supply of fresh air from outside, ensuring a continuous flow
of clean air into the tunnels and stations. This helps dilute and remove any pollutants or stale
air that may be present.
 Second, the ventilation system incorporates exhaust fans that remove the accumulated air,
pollutants, and any Odours from the tunnels and stations. By continuously extracting air, it
helps maintain a healthier and more pleasant environment for passengers and staff.
 Additionally, some metro systems employ air filtration systems as part of their ventilation
system. These filters help capture and remove particulate matter, dust, allergens, and other
pollutants present in the air. This further improves the air quality within the metro system,
making it safer and more comfortable for everyone. So, the ventilation system controls air
quality by supplying fresh air, removing stale air and pollutants, and incorporating filtration
systems to ensure a clean and breathable environment in the metro tunnels and stations.

6.  There are typically two types of ventilation systems used in metro
stations: natural ventilation and mechanical ventilation.
1. Natural ventilation relies on the natural airflow and pressure differences between the
inside and outside of the station. It involves the strategic placement of openings, such as
windows, vents, or shafts, to allow fresh air to enter and stale air to exit. Natural ventilation
is often used in open-air or semi-open-air stations, where the design takes advantage of
the surrounding environment to facilitate airflow.
2. Mechanical ventilation, on the other hand, utilizes mechanical equipment to control and
circulate the air within the station. This type of ventilation system includes fans, blowers,
and exhaust systems that actively move and exchange air. Mechanical ventilation is
commonly employed in underground or enclosed metro stations, where natural airflow is
limited or non-existent.

7. Station Air Conditioning
 Air conditioning is an important aspect of ensuring comfort in metro stations and
buildings. It helps regulate the temperature and humidity levels, creating a pleasant
environment for passengers and staff. Metro stations often have air conditioning systems
installed to maintain a comfortable temperature throughout the year. These systems
work by cooling the air and removing excess humidity, creating a cool and dry
atmosphere inside the stations. This is especially important during hot summer months
or in regions with high humidity.
 In addition to stations, certain buildings within the metro system, such as commercial or
service buildings, may also have their own air conditioning systems. These systems help
provide a comfortable environment for employees and visitors, ensuring a pleasant
experience. Overall, air conditioning systems play a vital role in maintaining a
comfortable and enjoyable atmosphere in metro stations and buildings, making the
commuting experience more pleasant for everyone.

8. How does air conditioning works
 In metro stations, air conditioning works by using a combination of cooling and ventilation
systems. The air conditioning system typically consists of three main components: the
cooling unit, the ventilation system, and the controls. The cooling unit is responsible for
cooling the air. It usually involves a refrigeration system that uses a compressor, condenser,
evaporator, and refrigerant to extract heat from the air and lower its temperature. The cooled
air is then distributed throughout the station through a network of ducts and vents.
 The ventilation system helps circulate the air and maintain a fresh environment. It involves
the use of fans and exhaust systems to bring in fresh air from outside and remove stale air
from within the station. This continuous airflow helps maintain good air quality and prevents
the buildup of odours or pollutants. The controls are used to regulate the temperature and
humidity levels in the station. They monitor and adjust the cooling and ventilation systems
based on the desired settings, ensuring a comfortable environment for passengers and staff.
By combining these components, the air conditioning system in metro stations helps
maintain a cool and pleasant atmosphere, even during hot and humid weather conditions. It
contributes to the overall comfort and convenience of passengers while they wait for their
trains or navigate through the station.

10. fire control systems
 In metro systems, fire control systems are of utmost importance to ensure the safety of passengers and
staff. These systems are designed to detect, control, and suppress fires that may occur within the metro
stations or trains. One common component of fire control systems is the fire detection system. It consists
of smoke detectors, heat detectors, and flame detectors strategically placed throughout the metro
stations and trains. These detectors are capable of sensing the presence of smoke, abnormal heat, or
flames, triggering an alarm to alert the authorities and passengers.
 Another crucial component is the fire suppression system. This system includes fire extinguishers,
sprinkler systems, and fire hydrants strategically placed in metro stations and trains. In the event of a fire,
these systems can quickly suppress or extinguish the flames, helping to prevent the spread of fire and
minimize damage. Additionally, metro systems often have emergency evacuation plans and procedures in
place. These plans outline the steps to be taken in case of a fire, including the evacuation routes,
assembly points, and communication methods to ensure the safe evacuation of passengers and staff.
 Overall, fire control systems in metro systems are designed to detect fires early, suppress them effectively,
and facilitate the safe evacuation of individuals. These systems are continuously monitored and
maintained to ensure their effectiveness in protecting the safety of everyone in the metro system

11. How fire control system works
 The fire detection system in metro systems typically consists of various types of detectors strategically
placed throughout the stations and trains. These detectors are designed to sense different signs of a fire,
such as smoke, heat, or flames.
 Smoke detectors are one of the primary components of the fire detection system. They are designed to
sense the presence of smoke particles in the air. When smoke is detected, the detectors send a signal to
the central control panel, which triggers an alarm to alert the authorities and passengers.
 Heat detectors are another important part of the system. They are designed to monitor the temperature
in the metro stations and trains. If the temperature rises above a certain threshold, indicating a potential
fire, the heat detectors send a signal to the control panel, triggering the alarm.
 Flame detectors are used to detect the presence of flames. They use specialized sensors to identify the
unique light patterns emitted by flames. When flames are detected, the flame detectors send a signal to
the control panel, activating the alarm. Once the fire detection system is triggered, the alarm alerts the
authorities and passengers, allowing them to take immediate action. It is important to note that the fire
detection system is continuously monitored and tested to ensure its reliability and effectiveness in
detecting fires as early as possible.

12. Here are some fire control systems used in
metros:
1. Gas fire suppression: This system continuously monitors fire-prone compartments. It
transmits data to a display in the driver's room and discharges extinguishing agents. The
system stores all data in a permanent memory, known as a black box.
2. Water mist system: This system is becoming the preferred fire protection for rail and
underground facilities, as well as road tunnels. Water mist can quickly suppress fire, smoke,
and heat, which can significantly improve life safety.
3. Fire fighting hoses: Fire hose cabinets are available at stations to handle large fires.
4. Emergency detrainment ramp: This is available in trains to evacuate passengers safely
during an emergency.
5. Fire alarm system: Small boxes with glass covers are placed near exit points. A person who
discovers a fire can use it to alert others.
6. Public address system: This system guides commuters in case of any emergency or fire.

13. Lifts and escalator
 In metro systems, lifts (also known as elevators) and escalators play a crucial role in providing convenient
and efficient transportation for passengers. Lifts are vertical transportation devices that allow passengers
to move between different levels of metro stations. They are especially important for passengers with
mobility challenges or those carrying heavy luggage. Lifts in metro systems are designed to
accommodate a large number of people and are equipped with safety features to ensure passenger
safety.
 Escalators, on the other hand, are moving staircases that transport passengers between different levels of
metro stations in a continuous upward or downward motion. They are designed to handle a high volume
of passengers and provide a smooth and efficient way to navigate the station.
 Both lifts and escalators in metro systems undergo regular maintenance and inspections to ensure their
safe and reliable operation. It's important for passengers to follow safety guidelines and use these
transportation systems responsibly. So, whether you're taking a lift to go up or down a level or hopping
on an escalator for a quick ride, these transportation systems make traveling in metro systems more
convenient and accessible for everyone.

15. Why there is need of Lifts and escalator in metro system?
 Lifts and escalators are essential in metro systems for several reasons. Firstly, they provide accessibility
for passengers with mobility challenges, making it easier for them to navigate between different levels of
the metro stations. This inclusivity ensures that everyone can use the metro system comfortably.
 Secondly, lifts and escalators improve the overall efficiency of the metro system by increasing passenger
flow. They allow for smoother and faster movement of passengers, especially during peak hours when
there is a high volume of people using the metro. This helps to reduce congestion and ensures a more
seamless travel experience.
 Additionally, lifts and escalators enhance the overall safety and convenience of the metro system. They
provide an alternative to stairs, making it easier for passengers carrying heavy luggage, parents with
strollers, or individuals with injuries to move around the station. This promotes a more user-friendly
environment and reduces the risk of accidents or injuries. In summary, lifts and escalators are a vital part
of metro systems as they improve accessibility, enhance efficiency, and prioritize passenger safety and
convenience. They contribute to creating a more inclusive and seamless transportation experience for
everyone.

16. Thankyou