Report on the atmospheric railway

1
Universidad Politécnica de Puerto Rico
Hato Rey Campus
Departamento de Ingeniería Mecánica
Feasibility Analysis of the Atmospheric Railway Concept in 2013
Mid-19th
Century Concept Art of Atmospheric Railway
Picture Origin: http://perrasmotornostalgi.blogspot.com/2012/10/the-atmospheric-railway.html
Gabriel A. Heredia Acevedo #79317
Eric Torres #47003
Julio Colon #55970

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Table of Contents
List of Figures...............................................................................................................................3-4
Introduction..................................................................................................................................5-7
Theory.........................................................................................................................................8-12
Problem Proposed..........................................................................................................................13
Results......................................................................................................................................14-21
Analysis of Results...................................................................................................................22-25
Conclusions....................................................................................................................................26
Recommendations..........................................................................................................................27
References......................................................................................................................................28

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List of Figures
1) Figure 1: Remnants of 22in pipe and rail (application of an atmospheric railway in U.K.)
Picture Origin: http://www.hows.org.uk/personal/rail/wwr/atmos.htm
2) Figure 2: Cross-section of the atmospheric train concept
Picture Origin: http://chestofbooks.com/crafts/mechanics/Engineer-Mechanic-
Encyclopedia-Vol2/Hallette-s-Atmospheric-Railway.html#.Ul6zSVD56So
3) Figure 3: Old Pumping Station at Torquay, U.K.
4) Figure 4: Frictional Force Model
5) Figure 5: Differential Pressure against Piston Idealization.
6) Figure 6: System Idealization
7) Figure 5: Idealization of the atmospheric railway problem 7.9
Picture Origin: Fundamentals of Engineering Thermodynamics Seventh Edition (Moran,
Shapiro, Boettner, and Bailey)
8) Figure 8: Porto Alegre Light Vehicle
PictureOrigin:http://www.trensurb.gov.br/paginas/galeria_projetos_detalhes.php?codigo_
sitemap=87&l=en-US&PHPSESSID=27cf0e0f466f557acac63b10f7565db8
9) Figure 9: Route to Porto Alegre Airport

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List of Figures (cont.)
10) Figure 10: Station at Porto Alegre Airport
11) Figure 11: Station at Jakarta Indonesia
Picture Origin: http://commons.wikimedia.org/wiki/File:TMII_Aeromovel_train.JPG

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Introduction
The name “atmospheric railway” provides good insight as for the concept that is being
developed goes. The system consists of a train being propelled from station to station by means
of atmospheric pressure. This concept was initially discussed by British engineer George
Medhurst by the end of the 18th
century, although his ideas were not implemented at the time.
By the mid-19th
century, Samuel Clegg, Jacob Samuda, and Joseph Samuda revived the idea and
created the first model by 1843.
The first application was on a segment of the Dublin and Kingston Railway in Ireland,
operating from 1844 to 1845. Other applications were effected in various parts of United
Kingdom, France, and even New York, although these efforts did not last very long either.
Recent applications of the atmospheric railway can be found in Brazil’s Porto Alegre
Metro system which connects to a terminal in the Salgado Filho International Airport.
Figure 1: Remnants of 22in pipe and rail (application of an atmospheric railway in U.K.)

6
Introduction (cont.)
The concept consisted of a piston which would be attached to the train and would be
propelled by means of atmospheric pressure and a partial vacuum in the system. The system
contained a pipe with a slot cut into it so that the piston may be connected to the train. To create
the vacuum the system needed a material that would permit the connection between the piston
and the train and not lose the vacuum (namely rubber compounds). There would be machines at
the stations to depressurize the pipe in front of the direction in which the user would want the
train to travel. That difference in pressure would cause the train to move in the direction of the
vacuum.
Figure 2: Cross-section of the atmospheric train concept
Picture Origin: http://chestofbooks.com/crafts/mechanics/Engineer-Mechanic-Encyclopedia-Vol2/Hallette-s-Atmospheric-
Railway.html#.Ul6zSVD56So
The train’s means for propulsion are simple in theory but the technology available during
the 19th
century was very limited and so was considered “too inflexible” for widespread use.
Future engineers eventually stopped considering this alternative and started looking into the use
of individual locomotives and other technologies, as we may see in our present.

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Introduction (cont.)
The theory involved includes pneumatic propulsion, material sciences, static and dynamic
force analysis, and thermodynamics, among other disciplines.
The advantages observed during research in this type of system include capacity to climb
at a steeper slope than usual, minimal infrastructure, economical maintenance, fuel efficiency,
green technology (passengers will not be affected by engine fumes, etc.), and increments in
system safety. Disadvantages to this system include increased difficulty in connecting railway
cars, increased difficulty in switching traction types (adapting to currently existing systems), and
difficulty finding commercially available materials. It should be noted that these claims need to
be verified.
Figure 3: Old Pumping Station at Torquay, U.K.
This report reconsiders the atmospheric railway’s feasibility incorporating today’s
technology to redesign this concept and to, potentially, motivate engineers to resurrect this
concept.

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Theory
A train is desired to move passengers from point A to point B, both being located along
the same track. This train system is to be propelled by a blower or vacuum powered by a motor.
The motor will blow against or pull on a piston which will then be connected to the train
assembly.
The system will be composed of a gas chamber with a piston to transfer the work into
motion. Air is selected as the gas for the system. The system is analyzed by using the first and
second law of thermodynamics, as well as the Ideal Gas Model and dynamic force analysis:
accounts for all
gravity loads on system.
is taken as the
frictional coefficient.
is the normal force
acting on the system.
is taken as all the
masses associated with
gravity loads.
is taken as the
gravitational acceleration.
Figure 4: Frictional Force
Model

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Theory (cont.)
With a design cruising speed for the train we have:
To determine the distance and time travelled to achieve cruising speed we have:
∫
√
Where,
 is the distance travelled to achieve cruising speed.
 is the kinetic energy required to achieve cruising speed.
 is the train’s mass, including all those masses associated with gravity loads.
 is the cruising speed.
Note that and
Knowing the force required to push the system and having a piston cross-sectional area, the
pressure differential may be calculated and so the required pressure to move the system as
follows:
Where,
 is the required pressure to accelerate the train to cruising speed.
 is the required pressure difference on both sides of the piston.
 is the atmospheric pressure.
 is the piston’s cross-sectional area.

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Theory (cont.)
Assign the system the initial conditions it will be exposed to. To analyze the system at steady
state and insulating the system, use the first law of thermodynamics applied to open systems and
the Ideal Gas Model as follows to determine conditions at the second state:
̅
̇ ̇ ( )
Where,
 is the gas pressure at a given state.
 is the specific volume of the gas.
 ̅ is the Ideal Gas Constant per molar mass for a given gas.
 is the absolute temperature at a given state.
 is the energy transfer rate (equal to 0 for steady state operation).
 ̇ is the work rate input by the blower/vacuum.
 ̇ is the system mass flux.
 and are the system enthalpy per unit mass at state 1 and state 2, respectively.
 and are the kinetic energy input per unit mass at state 1 and state 2, respectively.
 and are the potential energy input per unit mass at state 1 and state 2,
respectively.
Piston Face
(idealized)
Figure 5: Differential Pressure
against Piston Idealization.

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Theory (cont.)
Once conditions at state 2 are obtained, use the second law of thermodynamics to verify the
validity of the system:
̅ ∫ ( )
Where,
 is the change in entropy from state 1 to state 2.
 and are the entropies considering temperature only at state 1 and state 2,
respectively.
 ̅ is the entropy considering the change in pressure from state 1 to state 2.
 ∫ ( ) is the entropy associated with heat transfer at the system boundary.
 is the production of entropy.
Once the conditions for the train to reach cruising speed are obtained, analyze the system at a
third state operating at constant velocity. The initial conditions for this analysis will be taken as
the conditions at state 2 for the previous analysis. Note:
Compute distance and time to be travelled by train at this state:
Where,
 is the distance travelled at cruising speed.
 is the total distance travelled from point A to point B measured along the track
centerline.
 is the distance travelled by the train while accelerating and decelerating from
cruising speed.
 is the time the train travels at cruising speed.
 is the cruising speed.

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Theory (cont.)
Once the conditions at state 3 are obtained, recalculate the required work input using the
first law of thermodynamics applied to open systems. Verify the validity of the system from
state 2 to state 3 using the second law of thermodynamics.
To stop the train at point B, use the properties at state 1 and state 3 to compute required
work input using the first law of thermodynamics. Use the second law of thermodynamics to
verify the validity of the system. The system will require work to be done on the system to bring
it to a complete stop.
The total travel time is the sum of all the times during all the process.
Figure 6: System Idealization

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Problem Proposed
This paper presents an investigation that considers the feasibility of using the atmospheric
railway as a viable alternative to other types of trains as means of transportation in urban areas.
Various types of train systems used presently will be compared with a redesigned version of the
concept developed during the 19th
century. The problem (namely problem 7.9) arises from page
423 of the seventh edition of the Fundamentals of Engineering Thermodynamics textbook by
Moran, Shapiro, Boettner, and Bailey. The problem in the textbook states as follows:
“In the 1840s, British engineers developed atmospheric railways that featured a large-diameter
tube located between the tracks and stretching the entire length of the railroad. Pistons attached by
struts to the rail cars moved inside the tube. As shown in Fig. P7.9D, piston motion was achieved
by maintaining a vacuum ahead of the piston while the atmosphere was allowed to act behind it.
Although several such railways came into use, limitations of the technology then available
eventually ended this mode of transportation. Investigate the feasibility of combining the
atmospheric railway concept with today’s technology to develop rail service for commuting within
urban areas. Write a report, including at least three references.”
Figure 7: Idealization of the atmospheric railway problem 7.9
Picture Origin: Fundamentals of Engineering Thermodynamics Seventh Edition (Moran, Shapiro, Boettner, and Bailey)

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Results
Atmospheric Train:
Advantages
 Automated vehicles without drivers onboard.
 Silent vehicles without engine noise, engine rooms acoustically isolated.
 Security (Air propulsion system powered by electric fans).
 Pneumatic brake system of high reliability, more comfort at offset.
 Avoids wasting time in queues and traffic jams.
 Economy (low energy costs).
 The infrastructure is less expensive than monorails and trains.
 Environment: Electric motors without the emission of gaseous pollutants.
 Elevated structures are most simple and less expensive than common trains.
Disadvantages
 Usually design to travels short distances.
 Low speed train.
 Less comfortable than long distance trains.
 High initially cost.
 Possible air leaks in the pipes.

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Results (cont.)
Tram Train (trolley)
Advantages
 Low operational cost
 High capacity of passengers
 The ride is far more comfortable than that of a rubber-tyred bus.
 The trams stops in the street are easily accessible, unlike stations of subways and
commuter railways placed underground.
 Multiple entrances allow trams to load faster
 Some trams can adapt de capacity of passengers, adding more cars.
 Usually has a much longer lifetime than a bus.
Disadvantages
 Occupies a significant urban space.
 Tram tracks can be hazardous on bad weather conditions.
 The steel wheels of the trams are nosier.
 Poor suspension systems.
 Tram trains need a driver onboard.

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Results (cont.)
Metro Buses
Advantages
 Low operational cost.
 Operate by public or private companies.
 High capacity of passengers.
 The buses stops in the street are easily accessible, unlike stations of subways and
commuter railways placed underground.
 Multiple entrances allow buses to load faster.
Disadvantages
 Buses depend specifically on street traffic.
 Limited passenger capacity.
 Metro buses needs a driver onboard.
 Diesel (cost)

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Results (cont.)
Monorails
Advantages
 The system requires less maintenance than a road or train track.
 Monorails are also practically silent, as opposed to trains, which make a noise traveling
along rails.
 Runs around elevated tracks (system more efficient and less risk than busses).
Disadvantages
 Total electric units.
 Monorail it is limited to one track, if a section of track needs to be replaced, the entire
system needs to be shut down.
 Expensive to build initially, requires the elevated track and supports, which are more
costly than a basic railroad.
 Monorails need a driver onboard.

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Results (cont.)
Rapid Transit Train
Advantages
 Typically use various rail tracks.
 High capacity for passengers, more than other trains or buses.
 Located in undergrounds tunnels or elevated above street level.
 Organized, fast and effective system.
 The system is effective on a high passenger movement (big cities).
Disadvantages
 Total electric units.
 The system requires a frequently maintenance.
 Very Expensive to build, requires elevated rails and tunnels.
 Dangerous (underground tunnels accidents).
 Rapid transit trains need a driver onboard.

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Results (cont.)
A. Porto Alegre (Brazil)
 1 km single track (0.6 miles) connecting Trensurb Airport Station to Terminal 1 Airport
Salgado Filho.
 Travel time is approximately 90 seconds.
 Two light vehicles (150 and 300 passenger capacity).
 Two stations.
 Project cost is approximately $37.8 million.
 Transports 7,700 passengers per day.
Figure 8: Porto Alegre Light Vehicle
http://www.trensurb.gov.br/paginas/galeria_projetos_detalhes.php?codigo_sitemap=87&l=en-
US&PHPSESSID=27cf0e0f466f557acac63b10f7565db8

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Results (cont.)
Figure 9: Route to Porto Alegre Airport
Figure 10: Station at Porto Alegre Airport

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Results (cont.)
B. Jakarta (Indonesia)
 3.22km single track (2miles).
 50 kilometers per hour average speed.
 Capacity: 3 vehicles (Two vehicles were designed to carry 104 seated passengers and the
third one was designed for 48 seated and 252 standing passengers.
 6 stations
 The estimated cost of the project was $9 million (at an estimated 65 watts of power
consumption per passenger).
 1,000 passengers per day
Figure 11: Station at Jakarta Indonesia
http://commons.wikimedia.org/wiki/File:TMII_Aeromovel_train.JPG

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Analysis of Results
The atmospheric train (pneumatic train) is a technology for over 100 years, although it is
used very limited today. In Puerto Rico we have a big problem of traffic congestion and the
majority of citizens are not accustomed to using alternative transportation. In order to analyze
whether atmospheric train technology would be ideal for Puerto Rico we must analyze
transportation systems that are used on the island, and also systems of other urban areas.
As first we have the buses, this transport is established in May 1959 with The Puerto
Rico Metropolitan Bus Authority (AMA). This system is one of the first public transport
authorities in America, leaving behind the New York's MTA. The fixed or regular route operates
about 37 fixed routes serving the municipalities of San Juan, Carolina, Bayamón, Trujillo Alto,
Guaynabo, Levittown, Cataño and Loiza. Regular route currently has 243 active vehicles
providing service to 41,000 passengers on weekdays. This system has several advantages, it is
cheaper to travel on them, about $ 0.75, have multiple inputs and to travel on the streets have
easy access. But have several disadvantages, among them is that the passenger capacity is quite
limited (cannot change), depends on traffic, needs a driver to operate the bus and depend of fossil
fuels (diesel, natural gas).

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Analysis of Results (cont.)
Another type of urban public transport is the Tren Urbano (Rapid Transit Train). Puerto
Rico Department of Transportation (DTOP) established this transportation in December 2004 at
a cost of $2.28 billion. The system has 16 stations, 74 vehicles in total (two permanently coupled
pairs during peak hours) walking 10.7 miles (17.2 km) peoples of Guaynabo, Bayamón and San
Juan. The regular route serves approximately 43,000 passengers daily. Among its advantages is
that the current rate is $0.75, doesn’t depend on transit to operate, more than one rail track
(flexibility) and can transport a large group of passengers (72 seated and 108 standing). However
this system has several disadvantages, depends completely on an electrical source (high energy
cost), requires frequently maintenance to operate properly, completely dependent on a driver
onboard, can be dangerous in accidents (tunnels underground) and has a high initial cost of
construction. Besides the Tren Urbano route is limited, which means that buses are used as a link
to those places where the train doesn’t come. Another important factor is that the stations are too
large and expensive for the passenger flow. Finally the number of passengers is not as expected,
as the train was projected for 2010 would be transported 110,000 passengers daily.
There are other types of urban public transport that we don't see in Puerto Rico. The tram
trains is a type of transportation that we have seen on the island but in limited ways. Examples of
this are the trolleys, much like buses, with the difference that the route is quite limited. There are
other types of tram electric trains that have worked in many cities. Its advantages are that have a
unique rail to them and are easily accessible and transport rate is very low. The disadvantage
they have, like the trolleys and buses is that they depend on traffic in the area and passenger
capacity is limited. In addition to this means of transport, other cities can find monorails. This

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type of train has some differences when compared with the Tren Urbano. It depends only with a
a rail track to transport passengers and commonly we see elevated structures and underground
tunnels. Among its advantages is that it has a more modern design, require less maintenance than
Rapid Transit Trains and are practically silent, as Opposed to trains, they make a noise traveling
along rails.
Finally we present the atmospheric or pneumatic train as another type of urban
transportation. This technology is implemented for the 1830's on a small scale and over the years
began to be implemented in different cities. These trains use air pressure to provide the
propulsive force. Not much is known about these trains today, disappeared because the materials
that were used at that time were inadequate and the life of the system was very limited. Today
one company has again brought this technology implementing it atmospheric railway in
Indonesia and Brazil. In Indonesia design a route in a park that has 6 stations, 3 vehicles (Two
vehicles were designed to carry 104 seated passengers and the third one was designed for 48
seated and 252 standing passengers), carrying about 1,000 passengers daily. In Brazil designed a
route connecting two airports to help for the 2014 World Cup at a cost of $37.8 millions. The
train travels 1km, 2 stations, 2 vehicles (150 and 300 passengers), carrying 7,700 passengers per
day free. Also a company designs a prototype to transport passengers between cities (High Speed
Train), known as VECTORR project.
Atmospheric trains have some fundamental aspects that make it ideal for Puerto Rico.
First, the initial cost is not as high as the Tren Urbano because they have a track (rail)
structurally simpler, has light vehicles with simple stations. Another point in its favor is the air

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pressure dependence (Green technology). Also it would be more effective to use than buses or
trams because can transport a large group of passengers and modify that amount when required,
automated vehicles (does not require a driver on board to operate the train, more space in the
vehicle) and are fairly quiet. It is also a type of transportation that doesn’t require as strictly
maintenance as other trains and is very safe (single train track). But there are only a few
disadvantages to this type of transport. One is that has recently been designed only for short
lengths of 1km to 3 km, in our case would not be a big limitation because we could use it for
short-distance connections and test how it works. Also if you’re not given proper maintenance,
leaks could occur and affect the system piping. Finally, the initial cost is quite high, but
considering the initial costs of other types of transport wouldn’t’ be so excessive. In short,
citizens must understand that transportation systems are used to make life much easier. In Puerto
Rico we have the Tren Urbano and many citizens don’t’ use it, if we develop this new system on
the island, we must stop dependence of fossil fuels for transportation and focus on there are
systems that protect the environment and help to improve our daily lives such as the atmospheric
railway.

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Conclusion
After presenting in detail the atmospheric railway concept, historical background,
theoretical analysis of how it works, its advantages and disadvantages compared to other urban
transport we can conclude that this type of transport is possible to integrate it into the 21st
century in Puerto Rico. Initially, the atmospheric train didn’t evolve because the materials of the
period were inadequate, however at present we can integrate this system with existing
technology and make it more efficiently than in the past. Examples are the trains in Brazil and
Indonesia presented in the project, highly efficient systems that operate today. In Puerto Rico we
could build similar projects. We conclude that because the initial cost is low compare with other
trains, light vehicles and small stations, great passenger capacity, doesn’t need a driver onboard
and are pretty quiet. Another important reason that makes it possible in the island is the fact that
the atmospheric trains doesn't use fossil fuels, it makes the system more efficient and protects the
environment. In Puerto Rico, as in many other countries the cost of energy is high, with this type
of train we reduce electricity and petroleum consumption. Finally, this technology is ideal for
Puerto Rico, only we must educate the citizens to understand that they need to use systems like
these to help the environment and make daily life easier.

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Recommendations
 Analyze areas where the train is really necessary. This is mentioned because sometimes
we have misplaced construct facilities.
 Designing train stations according to the flow of passengers, avoid making large
structures to a limited flow of passengers.
 Ensure the cost of travel is appropriate.
 Educate the citizens to use the system. In Puerto Rico people prefer to use their vehicle
before use other urban transportation.
 Bring technology expert staff to supervise or perform the project.

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References
 http://www.urbanrail.net/am/america.htm
 http://www.dtop.gov.pr/transporte_urbano/det_content.asp?cn_id=6
 http://www.dtop.gov.pr/transporte_urbano/det_content.asp?cn_id=5
 http://www.dalkeyhomepage.ie/atmosphericrailway1843.html
 http://www.museum-
newtonabbot.co.uk/index.php?option=com_content&view=article&id=19
 http://www.aeromovel.com/
 http://www.trensurb.gov.br/paginas/galeria_projetos_detalhes.php?codigo_sitemap=87
 http://www.copa2014.gov.br/en/noticia/aeromovel-has-already-been-operating-24-years-
indonesia-using-brazilian-technology
 http://www.flightrail.com/
 http://en.wikipedia.org/wiki/Atmospheric_railway

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