1. Report on Summer Training In
Delhi Metro Rail Corporation
Submitted By :
Vivek Bajaj

2. DELHI MRTS PROJECT
The Delhi Metro is a Mass Rapid Transit System serving New Delhi and its
satellite cities of Gurgaon, Noida, Faridabad and Ghaziabad of the National Capital
Region in India. Delhi Metro has been ranked second among 18 international
Metro systems in terms of overall customer satisfaction in an online customer
survey. Delhi Metro is also the world's 13th largest metro system in terms of length
and 15th largest in terms of number of stations. Delhi Metro is India's third urban
mass rapid transport system (after the Kolkata Metro and Chennai MRTS) and the
first modern rapid transit system. As of July 2015, the network consists of five
colour-coded regular lines (Red, Blue, Green, Yellow, Violet), and a sixth line,
the Airport Express, with a total length of 194 kilometres (121 mi), serving 142
stations (with 6 more Airport Express stations), of which 38 are underground, five
are at-grade, and the rest are elevated. All stations have escalators, elevators, and
tactile tiles to guide the visually impaired from station entrances to trains. It has a
combination of elevated, at-grade, and underground lines, and uses both broad
gauge and standard gauge rolling stock. Four types of rolling stock are
used: Mitsubishi Rotem broad gauge, Bombardier Movia, Mitsubishi Rotem
standard gauge, and CAF Beasain standard gauge.
Delhi Metro Rail Corporation Limited (DMRC), a state-owned company with
equal equity participation from Government of India and Government of National
Capital Territory of Delhi built and operates the Delhi Metro. However, the
organisation is under administrative control of Ministry of Urban
Development, Government of India. Besides construction and operation of Delhi
Metro, DMRC is also involved in the planning and implementation of metro rail,
monorail and high-speed rail projects in India and providing consultancy services
to other metro projects in the country as well as abroad.
The power output is supplied by 25-kilovolt, 50-hertz alternating
current through overhead catenary. The metro has an average daily ridership of 2.4
million commuters, and, as of August 2010, had already carried over 1.25 billion
commuters since its inception. The Delhi Metro Rail Corporation has been
certified by the United Nations as the first metro rail and rail-based system in the
world to get "carbon credits for reducing greenhouse gas emissions" and helping in
reducing pollution levels in the city by 630,000 tonnes every year.
Planning for the metro started in 1984, when the Delhi Development Authority and
the Urban Arts Commission came up with a proposal for developing a multi-modal
transport system for the city. The Government of India and the Government of
Delhi jointly set up the Delhi Metro Rail Corporation (DMRC) registered on 3
May 1995 under The Companies Act, 1956. Construction started in 1998, and the

3. first section, on the Red Line, opened in 2002, followed by the Yellow Line in
2004, the Blue Line in 2005, its branch line in 2009, the Green and Violet Lines in
2010, and the Delhi Airport Metro Express in 2011.
BACKGROUND
The concept of a mass rapid transit for New Delhi first emerged from a traffic and
travel characteristics study which was carried out in the city in 1969. Over the next
several years, many official committees by a variety of government departments
were commissioned to examine issues related to technology, route alignment, and
governmental jurisdiction. In 1984, the Delhi Development Authority and the
Urban Arts Commission came up with a proposal for developing a multi-modal
transport system, which would consist of constructing three underground mass
rapid transit corridors as well augmenting the city's existing suburban railway and
road transport networks.
While extensive technical studies and the raising of finance for the project were in
progress, the city expanded significantly resulting in a twofold rise in population
and a fivefold rise in the number of vehicles between 1981 and
1998. Consequently, traffic congestion and pollution soared, as an increasing
number of commuters took to private vehicles with the existing bus system unable
to bear the load. An attempt at privatizing the bus transport system in 1992 merely
compounded the problem, with inexperienced operators plying poorly maintained,
noisy and polluting buses on lengthy routes, resulting in long waiting times,
unreliable service, extreme overcrowding, unqualified drivers, speeding and
reckless driving. To rectify the situation, the Government of India and the
Government of Delhi jointly set up a company called the Delhi Metro Rail
Corporation (DMRC) on 3 May 1995, with E. Sreedharan as the managing
director.
The first line of the Delhi Metro was inaugurated by Atal Bihari Vajpayee,
the Prime Minister of India, on 24 December 2002, and thus, it became the second
underground rapid transit system in India, after the Kolkata Metro. The first phase
of the project was completed in 2006, on budget and almost three years ahead of
schedule, an achievement described by Business Week as "nothing short of a
miracle".
BENEFITS
The Delhi MRTS is essentially a "social" sector project, whose benefits will
pervade wide sections of economy. The modified first phase will generate
substantial benefits to the economy by the way of:

4.  Time saving for commuters
 Reliable and safe journey
 Reduction in atmospheric pollution
 Reduction in accident
 Reduced fuel consumption
 Reduced vehicle operating costs
 Increase in the average speed of road vehicles
 Improvement in the quality of life
 More attractive city for economic investment and growth
OVER HEAD ELECTRIFICATION
OHE or Over Head Electrification is a major and an important system used to
provide electricity to several transport systems such as metros and railways. It
consists of masts, catenary, droppers and many other components.
Types of OHE:
 Regulated OHE: When a conductor is strung between two supports Sag is
produced. Spark less current collection by Pantograph under high speeds
requires that the contact wire should not only remain horizontal at the time
of stringing but should remain so under all conditions of wind pressure and
temperatures likely to encounter in service. Both Contact and Catenaries
together are regulated by Provision of Auto Tensioning Devices. The tension
in conductors is suitably compensated for any temperature variations by the
Auto Tensioning devices.
 Unregulated OHE: The conductors are terminated as fixed terminations on
either end. There is no compensation for temperature variations. OHE sags
in summer months and hogs in winter season. This type of Unregulated OHE
is not suitable for current collection at High Speeds as encountered on main
lines because tension varies inversely as temperature which affects the
stiffness of the line and its dynamic behavior. Re-tensioning of the
unregulated OHE is done periodically.
 Semi regulated OHE: Catenary is terminated as Fixed Termination on both
ends and Contact Wire is regulated by providing Auto Tensioning Devices.
Anti-creep provided at approximately midpoint of the Tension length. One
end of contact wire is connected to ATD and the other is fixed. This is used
for lengths less than 700m.

5.  Tramway type OHE: It does not contain messenger wire and has only
contact wire. Tension is required to be provided only in the contact wire.
Bridle wire is used in Tramway OHE. It is made of cadmium copper.
Basic Definitions
 Setting Distance (Implantation): The horizontal distance from the face of
the traction mast to the center line of the track.
 Span: The distance between the centerline of the adjacent supporting mast
for OHE.
o Max span – 72m (straight track)
o Min span -18m (curved track)
 Stagger: It is the horizontal distance of the contact wire from the vertical
plain through center of pantograph pan at contact surface.
For tangent track: ±200 mm.
For curved track: ±300 mm.

6.  Suspension Distance: The horizontal distance from center of eye of the
catenary suspension bracket to the face of the mast for single cantilever
assembly.
 Contact Height: It is the vertical height between contact wire & rail level.
 Encumbrance: The vertical distance between catenary & contact wire at
support is called Encumbrance.
 Track Centre: The distance between centerline with 2 adjacent tracks is
equal to1.675/2m.
 Tension Length: It is the length of conductors stretched between two
anchor points.
 Anti-Creep Wire: It is provided at/near the center of tension length to
prevent creeping of OHE. It is used between 3 masts to support the OHE.
 Feeding Post: It is the supply post where the incoming 25kV Feeder Lines
from substation are terminated and connected to OHE through circuit
breakers and interrupters.
 Sectioning & Paralleling Post (SP): It is the supply control post situated
midway between feeding posts & neutral sections and provided with
bridging and paralleling interrupters. There are 4 interrupters (itp): 2 for
bridging and 2 for paralleling. Main function of Bridging itp is feed
extension & that of paralleling itp is paralleling of Up & Dn OHE.
 Sub-Sectioning & Paralleling Post (SSP): It is a control post. 3 itp are
provided at each SSP i.e. 2 for bridging and one for paralleling.
 Sector (FP-SP): The section of OHE which can be energized by closing of
feeder CB’S at the substation.
 Sub-Sector: The smallest section of OHE which can be isolated remotely by
opening or closing itp (BM to BM).

7.  Elementary Section: Smallest section isolated by manual operation.
 Neutral Section (NS): It is provided with insulated OHE which separates
the sectors by 2 adjacent sub-stations which are normally connected to
different phases.
Equipment Used
 Cantilever Assembly
It is an insulated swiveling type structural member, comprising of different
sizes of steel tubes, to support and to keep the overhead catenary system in
position so as to facilitate current collection by the pantograph at all speed
without infringing the structural members. It consists of the following
structural members:-

8. 1. Stay arm– It comprises of seamless GI hollow tube diameter 38 mm,
thickness 4mm size and an adjuster at the end to keep the bracket tube in
position. It is insulated from mast by stay arm insulator.
2. Bracket tube– It comprises of seamless GI hollow tube diameter 49mm,
4.5mm thickness or seamless GI hollow tube diameter 38 mm (standard)
bracket tube and 14 insulated by bracket insulator. OHE is supported from
this member by catenary suspension bracket and catenary suspension clamp.
3. Register Arm– It comprises of diameter 25 mm. tube to register the contact
wire in the desired position with the help of steady arm.
4. Steady Arm– BFB (depot line)-Section of aluminum alloy to register the
contact wire to required stagger.
5. Special Steady Arm– special Steady arm of aluminum alloy tube of
diameter 36mm special bent type with I rod hot dip galvanized is used on
main line.
 Automatic Tension Device(ATD)
In DMRC the 1200kgf tension is required in the contact and messenger
wires, so that the pantograph constantly maintains contact with OHE. To
maintain this tension, Automatic Tension Device (ATD) is used. When the
tension length of OHE is less than 700m, only one end is attached to ATD
and the other end is fixed. Two types of ATD’s are used in DMRC:
1. Gas type ATD– This ATD is filled with nitrogen gas. When there is change
in atmospheric temperature, the gas also gets affected (contracts or expands)
and hence the tension is regulated in OHE.
2. 5 pulley block type ATD (Counter weight ATD) – This uses a five pulley
arrangement. It has a mechanical advantage of 5. In OHE the tension
required is 2400kgf (contact wire=1200kgf+catenary wire=1200kgf). Hence

9. the counter weight required is 2400/5=480kg. 12 weight blocks of 40 kg
each are used to provide this tension.
 Overlaps
In order to maintain continuity between two adjoining tension lengths the
following types of overlaps are used:
1. Insulated overlap (IOL)
2. Un insulated overlap (UIOL)
The height is so adjusted so that the pantograph smoothly moves from one
contact wire to the other contact wire.
 Integrated Transfer Link(ITL)
It is used for the following purposes
1. To reduce stray current
2. To reduce touch potential
3. To reduce electro-magnetic interference
4. To increase traction circuit impedance
5. To provide earth path to rail corridor
ITL’s are located at intervals of 2.5 km.

10.  Booster Transformers
These are power transformers, with a ratio of 1/1 usually, spaced a few
kilometers from each other along the track. They permit to force the return
current to flow through a cable specially installed for this purpose. The
Primary (HV) and Secondary (LV) windings of the Booster transformers are
connected in series with the OHE and the return Conductor respectively. The
booster Transformers of 150 kVA ratings are connected at Insulated
overlaps at intervals of approximately 2.66 km.
The midpoint of the return conductor between two Booster Transformers is
connected to the rail. Due to this arrangement flow of primary current in
primary winding induces an equal and opposite voltage in Secondary
winding of the BT. This induced voltage in the Secondary winding helps to
draw the return current from the rail, which ten flows in the return conductor
in opposite to the OHE current, thus nullifying the induction effect of the
latter.
 Section Insulator
The insulating element of a piece of equipment called section insulator
assembly which is used for separating adjacent sections of the overhead
traction line belonging to different elementary electrical section in the

11. normal condition and which provides a continuous mechanical and
electrical path for passage of the pantograph of electric rolling stock.
 Isolators
Isolator is a mechanical device which can make and break electrical circuit
on off load. It can withstand short-circuit current for a specified time.
 Rigid Overhead Contact System (ROCS)
The underground section of metro has an overhead conductor rail system
due to limited space available for which flexible overhead conductor system
is not feasible. Contact wire of conventional cross section is clamped to
Single Pole Isolator Double Pole Isolator

12. conductor rail profile (CR). CR is manufactured in partial lengths which are
connected with interlocking joints. CR is suspended from a hinged or gliding
support provided with insulators. To compensate temperature variations
longer CR sections are provided with expansion joints- two sections held by
means of a midpoint. The conductor rail profile is made of an aluminum
alloy and is manufactured by extrusion molding in 11.9m sections. The point
of transition from conventional overhead line to the conductor rail is
equipped with a transition bar, contact wire anchoring bar and endpoint
anchor. CR belonging to different sections is separated by a section
insulator.
Parallel routed CR is used as an alternative arrangement for expansion joints
and section insulators. Profile of the conductor rail- a 150 mm2 copper wire
is held by an aluminum rail. Plastic covers are put above the rails, a
safeguard measure for preventing copper/ aluminium corrosion.

13.  Dropper
1. In span dropper: It is used between catenary and contact wire. It transfers
weight from contact wire to catenary wire. It is made of electrolytic copper.
2. Register arm dropper: Used between suspension clamp and register arm
tube(RT), for horizontal arrangement of RT. It is also called inclined
dropper.
3. Raised register arm dropper: Used in out of run cantilever, suspension
clamp and RT.
4. Adjustable dropper: Used for smooth adjustment of SI.
5. Anti-wind dropper: It is used in push of location and is made of stainless
steel.
 Jumpers
Three types of jumpers are used:
1. H jumper-distributes current to contact wire
2. C jumper-functions as potential equalizer
3. G jumper-used in un insulated overlap (UIOL)
Cross section of jumper (in sq. mm):
H-26, C-75, G-164

14.  OHE Maintenance Cars
The following to vehicles are used:
1. CMTC (Catenary Track Maintenance Car) - It is used for OHE
maintenance. It is self-powered and has speed of 25 kmph on level track,
10kmph on curvature and 5kmph on points of crossings. It has jib,
crackle and pantograph on it. It is also used for stagger and contact wire
height adjustment.
2. OMV (Overhead maintenance vehicle) - Used for wiring of the OHE.
This is also self-powered. OMV is coupled with the CMTC as they have
same speeds on the level track.
POWER SUPPLY INSTALLATION
 Receiving Sub-Station (RSS): In it electricity is taken from the nearest
grid and supply to the following sub stations for their consumption of station
supply and for running of the metro. It consists of 2 sections:
1. Traction Sub-Station (TSS): Power supply fed for the operation of train. It
uses a transformer of 40 MVA since the load is high. It has a supply of 25kV
(single phase AC).
2. Auxiliary Main Station (AMS): It is for the local supply of the substations.
It uses a 15 MVA transformer and has a 3-∅ supply of 33 kV AC.
 Auxiliary Sub-Station (ASS): Each station has an ASS for the control
of its local supply. It also has 2 incomer circuits connected with interrupter

15. and circuit breakers which work on dc supply given from the 110kV battery
bank.
 Voltage Level Of Incoming Supply: Incoming supply to substations
are fed to 4 voltage levels: 220kV , 132kV , 66kV and 11kV.
SCADA
SCADA stands for Supervisory Control And Data Acquisition. As the name
indicates, it is not a full control system, but rather focuses on the supervisory level.
As such, it is a purely software package that is positioned on top of hardware to
which it is interfaced, in general via Programmable Logic Controllers (PLCs), or
other commercial hardware modules.
Common system components
A SCADA system usually consists of the following subsystems:
 Remote terminal units (RTUs) connect to sensors in the process and convert
sensor signals to digital data. They have telemetry hardware capable of
sending digital data to the supervisory system, as well as receiving digital
commands from the supervisory system. RTUs often have embedded control
capabilities such as ladder logic in order to accomplish boolean logic
operations.
 Programmable logic controller (PLCs) connect to sensors in the process
and convert sensor signals to digital data. PLCs have more sophisticated
embedded control capabilities (typically one or more IEC 61131-
3 programming languages) than RTUs. PLCs do not have telemetry
hardware, although this functionality is typically installed alongside them.
PLCs are sometimes used in place of RTUs as field devices because they are
more economical, versatile, flexible, and configurable.
 A telemetry system is typically used to connect PLCs and RTUs with
control centers, data warehouses, and the enterprise. Examples of wired
telemetry media used in SCADA systems include leased telephone lines and
WAN circuits. Examples of wireless telemetry media used in SCADA

16. systems include satellite (VSAT), licensed and unlicensed radio, cellular and
microwave.
 A data acquisition server is a software service which uses industrial
protocols to connect software services, via telemetry, with field devices such
as RTUs and PLCs. It allows clients to access data from these field devices
using standard protocols.
 A human–machine interface or HMI is the apparatus or device which
presents processed data to a human operator, and through this, the human
operator monitors and interacts with the process. The HMI is a client that
requests data from a data acquisition server.
 A Historian is a software service which accumulates time-stamped
data, boolean events, and boolean alarms in a database which can be queried
or used to populate graphic trends in the HMI. The historian is a client that
requests data from a data acquisition server.
 A supervisory (computer) system, gathering (acquiring) data on the process
and sending commands (control) to the SCADA system.
 Communication infrastructure connecting the supervisory system to the
remote terminal units.
 Various processes and analytical instrumentation.
Why SCADA Is Widely Accepted?
The major attraction of SCADA to metro is the ability to significantly reduce
operating labor costs, while at the same time actually improve system’s
performance and reliability. Information gathering within a station no longer
requires personnel to spend time wandering all over the site, and correspondingly
the frequency of field site inspections required at a station can be minimized.
Costly after-hours alarm call-outs can often be avoided since a SCADA system
will indicate the nature and degree of a problem, while the ability to remotely
control site equipment may permit an operator at home to postpone a site visit till
working hours. SCADA based alarming is also very reliable since it is in-house
and tied directly to process control.
A significant feature of a SCADA system, often not fully appreciated, is the
trending of data and nothing comes close for speed and ease of operation. When
graphically displayed, accumulated operating data often will indicate a developing

17. problem, or an area for process improvement. Reports can easily be generated from
this data utilizing other common software programs. It should be appreciated that
while a SCADA system is often complex to configure - it is extremely easy to
operate!
SCADA Architecture
A SCADA system includes input/output signal hardware, controllers, HMI,
networks, communication, database and software.
The term SCADA usually refers to a central system that monitors and controls a
complete site or a system spread out over a long distance (kilometers/miles). The
bulk of the site control is actually performed automatically by a RTU or by a PLC.
Host control functions are almost always restricted to basic site over-ride or
supervisory level capability. For example, a PLC may control the flow of cooling
water through part of an industrial process, but the SCADA system may allow an
operator to change the control set point for the flow, and will allow any alarm
conditions such as loss of flow or high temperature to be recorded and displayed.
The feedback control loop is closed through the RTU or PLC; the SCADA system
monitors the overall performance of that loop.

18. What Is Data Acquisition?
Data acquisition begins at the RTU or PLC level and includes meter readings and
equipment statuses that are communicated to SCADA as required. Data is then
compiled and formatted in such a way that a control room operator using the HMI
can make appropriate supervisory decisions that may be required to adjust or over-
ride normal RTU (PLC) controls. Data may also be collected in to a Historian,
often built on a commodity Database Management System, to allow trending and
other analytical work.
SCADA systems typically implement a distributed database, commonly referred to
as a tag database, which contains data elements called tags or points. A point
represents a single input or output value monitored or controlled by the system.
Points can be either "hard" or "soft". A hard point is representative of an actual
input or output connected to the system, while a soft point represents the result of
logic and math operations applied to other hard and soft points. Most
implementations conceptually remove this distinction by making every property a
"soft" point (expression) that can equal a single "hard" point in the simplest case.
Point values are normally stored as value-timestamp combinations; the value and
the timestamp when the value was recorded or calculated. A series of value-
timestamp combinations is the history of that point. It's also common to store
additional metadata with tags such as: path to field device and PLC register, design
time comments, and even alarming information.
A SCADA RTU [Remote Terminal Unit] performs remote control and monitoring,
protective relays provide protection, strip charts record metering (historical) data,
meter-dials display volts and amps and control handlers provide local control and
monitoring. SCADA IED [Intelligent Electronic Device] replaced mechanical relay
switches with computer microprocessor-based devices often called a PLC
[Programmable Logic Controller]. IEDs support GUI [Graphical User Interfaces]
which provide for more detailed, effective and versatile reports.

19. A Human Machine Interface
REMOTE TERMINAL UNIT
 An RTU, or Remote Terminal Unit is a microprocessor controlled
electronic device which interfaces objects in the physical world to a
distributed control system or SCADA system by transmitting telemetry data
to the system and/or altering the state of connected objects based on control
messages received from the system.
 The RTU connects to physical equipment, and reads status data such as the
open/closed status from a switch or a valve, reads measurements such as
pressure, flow, voltage or current. By sending signals to equipment the RTU
can control equipment, such as opening or closing a switch or a valve, or
setting the speed of a pump.
 The RTU can read digital status data or analogue measurement data, and
send out digital commands or analogue set points.
 The RTU connects to physical equipment, and reads status data such as the
open/closed status from a switch or a valve, reads measurements such as
pressure, flow, voltage or current. By sending signals to equipment the RTU

20. can control equipment, such as opening or closing a switch or a valve, or
setting the speed of a pump.
 The RTU can read digital status data or analogue measurement data, and
send out digital commands or analogue set points.
A Remote Terminal Unit
SCADA in DMRC
DMRC has most of its installed infrastructure based on the SCADA. From the air-conditioning
to the fire exhaust system, from power control to the lightening system everything gets under
the hands of a single SCADA operator sitting in front of the HMI.
There are mainly two kinds of SCADA used in DMRC
BMS-the BUILDING MANAGEMENT SYSTEM
TRACTION POWER CONTROL

21. Each station is remotely connected to the OCC-Operational Control Center.It
has the control over each and every station and possesses the highest command
priorty.Infact the various modes of operation such as Emergency and
Congestion are controlled by this only.
It is also responsible for the control of the traction power control
tvs
The TVS consists of two reversible Tunnel Ventilation Fans (TVF) located at each
of the north and south end tunnel ventilation plant rooms. These fans operate to
provide forced ventilation in the tunnels during the congestion and emergency
modes. For each of the tunnel ventilation fans, corresponding Tunnel Ventilation
Dampers (TVD) are installed for controlling the air flow as required. Fixed
eversible Tunnel booster Fans (TBF) and supply nozzles maintain the required
thrust in the tunnel. All the Reversible fans are capable of accepting a direction
reversal command without any time delay.
Figure 3: Tunnel ventilation Fans (TVF) in emergency mode

22. Figure 2: Track-way Exhaust Fan system

27. B. Modes of Operation
There are four modes of operation that were manually created to suite different
conditions [7]. Each mode has a corresponding manner in which the components
operate. The four modes of operation are: 1) Normal: the operation of station and
tunnel is going as expected and the TVS is not engaged. 2) Congestion: Meant for
situations like natural disaster in which people tend to seek shelter in the station
and there is an uncertain situation. 3) Emergency: Meant for the extreme situations
like fire and flooding etc. 4) Maintenance: This mode is activated mostly at night
but may be used if maintenance is required even during the day time in some
urgent circumstances. In the congestion mode, the train has stopped in the tunnel
beyond a predetermined time period and this causes the tunnel temperature to rise
[8]. Consequently, it prevents the train air conditioning from working properly. To
assist the operator, the tunnel temperatures in each section are monitored by a
temperature sensor (one located on each track in a tunnel) and sent to the relevant
Station Control Room (SCR) and the operational Control Center (OCC). The TVS
system then follows the command from the control center.
Figure 2: Track-way Exhaust Fan system In the event of Congestion, to prevent the
accumulation of warm tunnel air around idling train leads to activation of TVF
push – pull mode as shown in figure 2. The nearest station acts in supply mode and
farthest station acts in extract mode. The TVS can operate in various modes as
listed below:
1) Open mode: The track-way exhaust fans can operate in both the directions i.e. to
supply or to extract air. The supply or extraction process can be executed both up-
line and down-line. The tunnel ventilation fans in extract direction can operate only
in open mode i.e. discharge to atmosphere. 2) Close mode: The track-way exhaust
fans can operate in operate only in supply mode up-line and down-line. In the
emergency mode, an area of the tunnel is under fire or contains smoke. Emergency
conditions are the TVS operational modes for any variety of occurrences including
transit vehicle malfunctions, derailment or fire that may result in smoke conditions
in the tunnel. The TVS of one of the station acts in a supply mode and that of the
other station acts in an extract mode depending upon the location of the fire and the
direction of safe passage for the passengers as shown in figure 3.
Figure 3: Tunnel ventilation Fans (TVF) in emergency mode V. DESIGN
PRACTISES AND EXAMPLES ABROAD A. London Underground Rail System
Colloquially referred to as ‘The Tube’, it is the world‟s oldest underground rail
system consisting of 270 stations and around 400 kilometers of track, making it the
second longest metro system in the world by route length after the Shanghai Metro.
Lines on the Underground can be classified into two types: subsurface lines and
deep-level lines [9]. The subsurface lines, which were dug by the cut-and-cover
method while the deep-level or tube lines, which were bored using a tunneling

28. shield. The Tube has no provision of air conditioning; however the new S-stock
trains however will have air conditioning system for providing a comfortable
environment for commuting. In summer, temperatures on parts of the Underground
can become very uncomfortable due to its deep and poorly ventilated tube tunnels.
Posters may be observed on the Underground network advising passengers to carry
a bottle of water to help keep cool without the air conditioning. Each line is being
upgraded to improve capacity and reliability, with new computerized signaling,
automatic train operation (ATO), track replacement and station refurbishment, and,
wherever needed, new rolling stock.
According to the concept design for the smoke control systems throughout tunnels
to separate the two areas with platform edge doors and provide separate smoke
control systems in both areas. The tunnels have a longitudinal ventilation system
controlled from fans located at either end of the station which also provides an
Over Track-way Exhaust (OTE) system above the tracks. In case of a fire the OTE
would clear the smoke from the tunnel space, although smoke would inevitably
enter the platform areas through the open train and the platform edge doors. To
ensure tenable conditions, the mechanical smoke exhaust system located on the
platform would start operating. For designing of the smoke control system,
Computational Fluid Dynamics (CFD) [13] smoke modeling has been carried out
using Fire Dynamics Simulator software. The station design includes twin-bore
tunnels throughout the line with crossovers between the two bores at three
locations along the tunnel. At these locations the TVS is designed to reduce smoke

29. spread between the two bores for all fire scenarios near the crossover. The CFD
analysis demonstrated that in all fire scenarios near the crossover sections, smoke
spread would be reduced in the non-incident tunnel. VI. SUGGESTIONS AND
IMPROVEMENTS The practice of halting trains in the tunnel during congestion at
DMRC places a lot of burden on the TVF system and also causes passenger
inconvenience. Trains halted in the tunnel run the risk of having their air-
conditioning units unload as dwelling trains cause the temperatures in the tunnel to
rise. Also, for the purpose of conceptual design, the fan sizing is based on the
logical course of only one train being permitted in the ventilation zone. If more
than one train is to be allowed, added heat and increased ventilation equipment are
to be considered. During an incident of vehicular congestion, the Train Service
Regulator should halt as many subsequent DMR trains as possible at the station
itself. This would place lesser burden on the TVF and allow the passengers to
alight to subsequent trains into the station. Currently the DMR Tunnel Ventilation
System is using the closed system concept and the open system concept. The open
system requires the sir-conditioning to use 100% outside whereas in the closed
system the station air is re-circulated to the station air-conditioning system. The
Platform Screen Doors (PSD) concept which is not being employed may also be
incorporated in the designing of future underground metro systems. Platform
screen doors are actually solid, transparent barriers that are aligned with the vehicle
doors such that the passenger entry/exit to the DMR trains is automated. The PSD
system has the inherent ability to isolate the air-conditioning from the hot & humid
air in the tunnels and also partially prevent the smoke and toxic gases from
entering the platform in emergency and congested conditions. They also provide
the least operating cost for the environment control systems. On the site, another
improvement may be to set up the tunnel at the top of exhaust pipe while the
ventilation system and smoke extraction system be set up separately using vertical
exhaust to replace the horizontal direction of the smoke method

30. ECS
During initial planning for underground metro stations, it soon became apparent that one of the most
critical and vital considerations in transit tunnel design was the need for a well-founded environmental
control system. This system would include temperature and humidity control, circulation of fresh air (to
meet both normal and emergency requirements), and safety features in case of fire.
Chiller plant
Chilled water-based cooling systems are frequently used to air condition large office buildings or
campuses that encompass multiple buildings. They represent a large investment from the perspective of
first cost, physical space they require within the building, as well as energy and maintenance cost. Yet
despite these fiscal and spatial impacts, many chiller plants do not reach their potential from the
standpoint of energy efficiency. In the past, California’s Title 24 Energy Efficiency Standards for
NonResidential Buildings did not have particularly aggressive efficiency standards for chillers. This all
began to change with the 2001 revision of the code and the latest 2008 requirements have become
even more demanding. Since the 1970’s, chiller efficiency requirements have increased by as much as 40
percent. Chiller plants that easily complied with older Title 24 Standards might not be efficient enough
to meet the 2008 Standards, which took effect on January 1, 2010. The strategies discussed in this
design brief can provide the basis for designing chilled water cooling systems that can beat the more
aggressive 2008 Title 24 Energy Efficiency Standards by 30 percent or more. Introduction All air
conditioning systems require a means for generating the cooling effect that offsets building heat gain
due to external loads (sun, wind, outdoor temperature) and internal loads (heat and moisture from
people, lights, and equipment). In smaller buildings and residential applications, this is usually energy
design resources Though more costly to install and more complicated to operate, a chiller plant offers a
number of benefits over simple packaged cooling units, including greater energy efficiency, better
controllability, and longer life. CONTENTS Introduction 1 What Level of Efficiency Is Achievable Today? 4
Characteristics of an Efficient Chiller Plant 6 How to Minimize the Cost of an Efficient Chiller Plant 7 Five
Design Strategies for Efficient Chiller Plants 8 Conclusion 25 For More Information 26 Notes 27 CHILLER
PLANT EFFICIENCY design brief PAGE 2 CHILLER PLANT EFFICIENCY accomplished with an air-based
system that ducts cold air from the point of generation (usually on the roof) to each space in the
building that requires cooling. Larger buildings and multiple building campuses usually use a chiller plant
to provide cooling. In such systems, chilled water is centrally generated and then piped throughout the
building to air handling units serving individual tenant spaces, single floors, or several floors. Ductwork
then runs from each air handler to the zones that are served. Chilled water-based systems result in far
less ductwork than all-air systems because chilled water piping is used to convey thermal energy from
the point of generation to each point of use.