Rail vehicle having a machine room and having at least
one driver's cab, and method for producing an excess
pressure in the machine room in conjunction with the
air conditioning of at least one driver's cab
Description
The present invention relates to a rail vehicle, for
example a rail power vehicle, in particular a
locomotive, a power head or a power car for a rail
vehicle train set, in particular a power head for heavy
rail vehicle train sets, for example for long-distance
trains, goods trains and regional trains, with the rail
vehicle having a system for the air-conditioning of the
at least one driver's cab. The present invention also
relates to a method for producing an excess pressure in
the machine room in conjunction with the air-
conditioning of at least one driver's cab.
The machine room of such vehicles serves to accommodate
electrical devices which are required in particular for
the operation of the rail vehicle, for example of
electrical components which are provided for the supply
of energy to an electrical traction drive, and to
accommodate auxiliary units which do not directly serve
for driving the vehicle, for example a compressed air
production device. Said electrical and other devices
are sensitive to contamination. The machine room should
therefore be kept as free from dust as possible. The
service life of said devices is otherwise limited, and
their failure rate increases.
To achieve this object, EP 2 127 991 Al, for example,
describes a locomotive which has two driver's cabs and
a machine room, wherein to cool the machine room and at
least one driver's cab, at least one cooling unit is
provided and a duct-shaped line system is provided for
conducting an air flow cooled by the cooling unit. The
line system makes it possible for the cooled air to be
guided through openings, in such a way that the cooled

air impinges in a targeted fashion on the components to
be cooled or is conducted into cabinets with components
to be cooled. In one exemplary embodiment, the
locomotive has two driver's cabs which are unoccupied
or occupied depending on the direction of travel. In a
first embodiment, an air-conditioning unit is arranged
in each of the two driver's cabs. The air-conditioning
unit of the unoccupied driver's cab is provided for
cooling the machine room, while at the same time the
air-conditioning unit of the occupied driver's cab is
used exclusively for the air-conditioning of said
driver's cab. In a second embodiment, a central air-
conditioning unit is. provided in the machine room. In
this case, cooled air is introduced into a line system
which extends in a T-shape through the machine room and
into the two driver's cabs, and said cooled air is
guided via said line system into the occupied driver's
cab, while the line system remains closed at the
unoccupied driver's cab, such that no cooled air can
enter there.
JP 10-129476 A specifies an air-conditioning unit for
rail vehicles having an internal fan, which air-
conditioning unit is fastened under the floor of the
vehicle. The air-conditioning unit comprises a first
fan for the supply and discharge of air, and also
comprises two evaporators and a second internal fan.
The air sucked in by the first fan is cooled by the
first evaporator. The cooled air is mixed with air from
the interior space of the vehicle, and the resulting
air mixture is cooled in a further evaporator. The
second internal fan blows the cooled air into the
interior space of the vehicle.
With the known air-conditioning systems, it is duly
possible to cool an interior space of a vehicle to an
adequately low temperature. EP 2 217 991 Al states in
this regard that the cooling of the electrical and
electronic components is necessary to reduce the
failure rate of these components. For this purpose, in

the rail vehicle described in said document, the cooled
air is directed in a targeted fashion at the
components. However, it has been found that the failure
rate nevertheless cannot be reduced to an adequate
extent. Furthermore, it must be taken into
consideration that the costs for manufacturing a rail
vehicle can be high if a plurality of air-conditioning
units are used, as in the embodiment specified in EP 2
217 991 Al.
Said problem is solved by means of the rail vehicle
having a machine room and having at least one driver's
cab according to Patent Claim 1 and the method for
producing an excess pressure in the machine room in
conjunction with the air-conditioning of at least one
driver's cab of the rail vehicle according to Patent
Claim 12. Preferred embodiments of the invention are
specified in the subclaims.
The rail vehicle according to the invention has a
machine room and also at least one driver's cab. The
rail vehicle may for example be a locomotive, a power
head or a power car for a rail vehicle train set, in
particular a power head for heavy rail vehicle train
sets, for example for long-distance trains, goods
trains and regional trains.
The rail vehicle according to the invention comprises
an air-conditioning system which is provided for the
air-conditioning of at least one driver's cab and which
at the same time produces an excess pressure in the
preferably adjacent machine room. According to the
invention, the air-conditioning system comprises a
first air guide for conducting fresh air into the at
least one driver's cab, and a second air guide for
transferring at least a part of the fresh air
introduced into the at least one driver's cab into the
machine room.

Accordingly, the method according to the invention for
producing an excess pressure in the machine room in
conjunction with the air-conditioning of the at least
one driver's cab of the rail vehicle comprises
introducing fresh air into the at least one driver's
cab and additionally transferring at least a part of
the fresh air introduced into the at least one driver's
cab into the machine room.
With the invention, it is achieved that the air which
is introduced into at least one driver's cab, and which
is if appropriate already filtered and/or cooled, by
means of the air-conditioning system is at least
partially transferred into the machine room, such that
an elevated air pressure in relation to the environment
is generated in the machine room. In this way, it is
achieved that the air introduced into the machine room
contains significantly lower amounts of impurities
and/or moisture than fresh air entering into the
machine room directly from the outside, such that the
reliability of electrical and other components situated
in the machine room is optimized. This is because, with
every additional supply of fresh air into the machine
room, the amount of impurities introduced and/or
moisture infiltrating into the machine room is
increased. Since, for the operation of the machine room
in the vehicle, it is adequate for a relatively small
amount of air to be introduced via the at least one
driver's cab, the introduction of impurities and/or
moisture into the machine room is minimized. At any
rate, it is preferable for only that amount of air
which is presently required for maintaining a slight
excess pressure to be transferred from the at least one
driver's cab into the machine room, such that the
reliability of the components in the machine room is
not put at risk. By means of the transfer of the fresh
air introduced into the at least one driver's cab into
the machine room, it is achieved that any impurities
contained in the fresh air are retained already in the
at least one driver's cab by virtue of being deposited

there. The transfer of the fresh air introduced into
the at least one driver's cab into the machine room is
also sufficient to maintain in the machine room an
elevated internal air pressure (in particular a slight
excess pressure) in relation to the environment. With
the elevated air pressure, it is ensured that
impurities and/or moisture cannot infiltrate from the
outside into the machine room even if the machine room
is not fully sealed off with respect to the
environment, since an infiltration of impurities and/or
moisture is prevented by the excess pressure.
In contrast, for optimizing the reliability of the
electrical and other components, it has been found that
branching off air from a traction motor blower in order
to produce the excess pressure in the machine room is
unsatisfactory, because this would cause additional
impurities and moisture to be introduced into the
machine room. The installation of separate machine room
blowers which suck in fresh air has also proven to be
disadvantageous. These methods do not permit permanent
machine room filtering which reliably retains dust of
all degrees of fineness and also moisture.
In any case, air is introduced into the at least one
driver's cab in order to supply fresh air to the person
present therein. According to the invention, said fresh
air is not discharged in an undefined manner but
rather, after being introduced into the driver's cab,
is transferred into the machine room.
The air-conditioning system comprises for example at
least one cooling element and may therefore be capable
of cooling the at least one driver's cab. Furthermore,
the air-conditioning system may also comprise filter
elements, guide elements for the air, for example guide
ducts, pipes and the like, switching means for shutting
off the passage of air through the guide elements, and
the like. A cooling element may be situated at any
desired technically preferable location in or on the

vehicle. A plurality of cooling elements may be
arranged at different locations in or on the vehicle.
In a preferred embodiment of the invention, the air-
conditioning system comprises cooling the fresh air as
it is introduced into the at least one driver's cab,
such that cooled air is produced. The cooling is
realized by means of at least one cooling element, for
example one or more evaporators of a refrigeration
machine or thermoelectric cooling elements or other
cooling elements.
In a further preferred embodiment of the invention, the
air-conditioning system comprises machine room
filtering as the air is transferred from the driver's -
cab into the machine room. Said filtering comprises at
least one machine room filter device. Filter devices
which can be used here are fundamentally known in the
field of the invention and are formed by corresponding
holders and materials composed for example of
nonwovens, or other gas-permeable materials, fastened
therein. With these means, it is achieved that the air
introduced into the at least one machine room is at
least substantially free from impurities and/or
moisture.
In yet a further preferred embodiment of the invention,
the air-conditioning system comprises at least one
machine room air delivery device, for example
comprising at least one machine room blower / at least
one machine room fan, for transferring the fresh air
component of the driver's cab air into the machine
room. Such devices are also known in the field of the
invention and are used in air-conditioning technology.
Through the use of at least one machine room air
delivery device, the delivery of the cooled air into
the machine room can be carried out as a function of
the delivery of the fresh air into the at least one
driver's cab. The air pressure in the at least one
driver's cab differs from the air pressure in the

machine room in that an excess pressure is produced in
the machine room and at the same time approximately
normal pressure (corresponding to the air pressure
outside the rail vehicle) is maintained in the at least
one driver's cab. The at least one driver's cab can
therefore be supplied permanently with fresh air, while
this may be avoided for the machine room, and an air
pressure is set in the machine room which is higher
than the air pressure prevailing outside the vehicle.
In this way, it is achieved that fresh air does not
also infiltrate into the inside through leaks in the
outer walls of the machine room and thereby entrain
impurities and/or moisture, but rather in fact air can
at most pass out of the machine room to the outside
through leaks and other openings.
The machine room air delivery device and the machine
room filter device may be combined in a machine room
air treatment device. The machine room air treatment
device may be accommodated either on the roof of the
rail vehicle or below the vehicle or in the machine
room of the vehicle or preferably in the region of the
partition between at least one driver's cab and the
machine room.
It has therefore been found in particular that the
cleanliness of the air fed into the machine room is
dependent primarily on the quality of the filtering. At
least one machine room filter device may be arranged
either on the suction side or on the pressure side of
the machine room blower or fan or both on the suction
side and on the pressure side thereof.
In yet a further preferred embodiment of the invention,
the machine room is of substantially air-tight design,
such that as air is transferred into the machine room,
an elevated pressure in relation to the environment is
generated in the machine room. "Substantially" means
that, at most, the housing surrounding the machine room
has leaks which oppose complete closure to the outside.

The walls of the housing are otherwise air-tight. By-
means of the at least one machine room air delivery-
device, which may also serve as a pressure generating
means for producing an elevated air pressure in the
machine room, an internal air pressure which is
elevated in relation to the ambient air pressure is
produced in the room region to be air-conditioned in
the machine room.
In yet a further preferred embodiment of the invention,
the air-conditioning system also comprises driver's cab
filtering as the fresh air is introduced into the at
least one driver's cab. Said filtering comprises at
least one driver's cab filter device. Such filter
devices are also known in the field of the invention.
As a result of the additional filtering of the fresh
air as it enters into the at least one driver's cab,
particularly clean and dry air is produced, such that
the problems of the known air-conditioning systems for
rail vehicles can be easily resolved. The air-
conditioning system may furthermore comprise in each
case one driver's cab air delivery unit for sucking the
fresh air from the outside into the at least one
driver's cab. The driver's cab air delivery units
comprise in each case one driver's cab air delivery
device, for example comprising at least one driver's
cab blower / at least one driver's cab fan. This may be
arranged upstream, downstream or both upstream and
downstream of the driver's cab filtering as viewed in
the air flow direction.
In yet a further preferred embodiment of the invention,
the air-conditioning system also comprises at least one
closing device which prevents the air which has been
transferred into the machine room from flowing back
into the at least one driver's cab. Said closing device
may be a non-return flap, though self-evidently may be
any other device suitable for this purpose, for example
a valve which closes automatically or through external
actuation if air seeks to escape from the machine room

back into the driver's cab. Said closing device serves
in particular to maintain an adequate excess pressure
in the machine room without the need for a continuously-
elevated inflow of air into the machine room. In
particular, said closing device serves to maintain the
excess pressure, once it has been reached, even when
there is the risk of said excess pressure being
dissipated on account of a malfunction, for example in
the event of failure of at least one of the machine
room air delivery devices.
In yet a further preferred embodiment of the invention,
the air-conditioning system also comprises a
recirculation of a first part of the fresh air
introduced into the at least one driver's cab, and an
injection of a second part of the fresh air into the
machine room. For this purpose, a flow of air formed in
the driver's cab branches into the first and the second
part, with the first part being introduced back into
the driver's cab (being recirculated) and the second
part being transferred into the machine room. By means
of the corresponding actuation of the fans, it may be
ensured that the amount of air delivered into the
machine room is at all times only as large as the
amount supplied as fresh air to the driver's cab, such
that a vacuum in the driver's cab is avoided. The
infiltration of impurities and/or moisture into the at
least one driver's cab and therefore also the
infiltration thereof into the machine room is thereby
minimized.
In yet a further preferred embodiment of the invention,
the air-conditioning system also comprises cooling of
the first part of the recirculated fresh air.
Continuous cooling of the fresh air recirculated in the
at least one driver's cab is obtained in this way. For
cooling, it is again possible for at least one cooling
element to be used, for example one or more evaporators
of a refrigeration machine or thermoelectric cooling
elements or other cooling elements.

The abovementioned cooling of the recirculated air may
also be realized by means of the cooling elements
already mentioned above, which are provided for cooling
the fresh air introduced into the at least one driver's
cab.
In yet a further preferred embodiment of the invention,
the air-conditioning system additionally comprises
recirculation filtering of the first part of the
recirculated air. Said filtering comprises at least one
recirculation filtering device. By means of continuous
filtering of the recirculated air, the level of
impurities and/or moisture therein is reduced further,
such that the air transferred into the machine room
also becomes cleaner and/or drier than would be the
case without this measure. The recirculation filtering
may be identical to the driver's cab filtering of the
fresh air introduced into the at least one driver's
cab, such that the fresh air and the recirculated air
originating from the driver's cab are conducted through
the same driver's cab filter device. It is however
alternatively possible for two different filter devices
to be provided, specifically a recirculation filter
device for filtering the recirculated air component and
a driver's cab filter device for filtering the fresh
air continuously newly supplied to the driver's cab.
In yet a further preferred embodiment of the invention,
the air-conditioning system comprises at least one
refrigeration machine, of which at least one evaporator
serves for cooling the fresh air. Such an evaporator is
a cooling element for the air to be cooled.
Refrigeration machines are known and typically comprise _
at least one evaporator, at least one compressor, at
least one condenser and at least one expansion valve in
at least one circuit for a refrigerant. The at least
one evaporator serves to absorb heat from the
environment into the refrigerant. The absorbed heat
quantity is inter alia discharged from the refrigerant

again in the at least one condenser. The at least one
evaporator therefore serves as a heat sink, and
therefore as a cooling element for cooling the air.
When using a refrigeration machine in the rail vehicle
according to the invention, the at least one evaporator
is preferably integrated into a driver's cab air
treatment device in order to act therein as a cooling
element for the fresh air to be cooled. At least one
cooling element, also preferably at least one blower or
fan and also preferably a filter device may be combined
in the driver's cab air treatment device. The at least
one refrigeration machine therefore comprises in each
case one evaporator for cooling the air, with the at
least one evaporator preferably being in each case a
constituent part of a driver's cab air treatment device
of the air-conditioning system in which the cooled air
is produced.
At least one driver's cab air treatment device is
preferably provided, for example in each case one air
treatment device for each driver's cab. Air is cooled
in the driver's cab air treatment devices and then
introduced into the respective driver's cab.
The one or more evaporators may be installed upstream
or downstream of the abovementioned driver's cab filter
device as viewed in the flow direction of the air used
for air conditioning. If two filter devices are used,
specifically a driver's cab filter device for filtering
the introduced fresh air and a recirculation filter
device for filtering the recirculated and if
appropriate already cooled air from the driver's cab
which is provided for being introduced back into the
driver's cab, said two filter devices are installed
upstream of the evaporator as viewed in the flow
direction of the air. In the case of the one or more
evaporators being installed downstream of the driver's
cab filter device, it is possible for particularly
clean filtered air to be conducted through the one or

more evaporators, such that the risk of the one or more
evaporators also being contaminated is reduced.
The at least one driver's cab air treatment device may
in particular be arranged within at least one of the
driver's cabs. Said at least one driver's cab air
treatment device may alternatively also be arranged
outside the driver's cabs, in particular outside the
rail vehicle, for example on the roof or - less
preferably - under the floor of the rail vehicle. Self-
evidently also preferable is an arrangement in the
driver's cab, since this provides encapsulation against
heat and impurities infiltrating from the outside.
Furthermore, no additional space within the vehicle
profile predefined by a rail operator need be reserved
for this device.
Instead of a refrigeration machine comprising an
evaporator, compressor, condenser and expansion valve,
it is also possible for a thermoelectric cooling
element or some other cooling element to be used.
The machine room air treatment device and the driver's
cab air treatment device may be combined in a common
air-conditioning unit and are constituent parts of the
air-conditioning system.
The present invention will be explained in more detail
on the basis of the figure described below, in which,
in detail:
Figure 1 shows a schematic longitudinal sectional
illustration of a part of a rail vehicle
according to the invention.
In the figure, the same reference numerals are used to
denote elements with the same function.
Figure 1 shows a schematic longitudinal sectional
illustration of the front part of a rail vehicle

according to the invention, for example of an electric
locomotive. Shown on the right-hand-side of the
illustration is the driver's cab 1. Situated at the
left-hand side adjacent to the drivers cab 1, and
separated from the latter by a wall 10, is the machine
room 2 of the vehicle. The wall 10 may additionally
have a door which divides the two rooms and which
preferably closes in a gas-tight fashion (not
illustrated). A diagrammatic illustration of electrical
devices situated in the machine room 2, for example of
electronic devices with electronic and/or
microelectronic devices for controlling the operation
of the vehicle, has been dispensed with for the purpose
of providing a clearer illustration of the invention.
Installed on the roof of the rail vehicle in the region
of the driver's cab 1 is an air-conditioning unit 3.
The air-conditioning unit 3 could however also be
arranged under the floor of the vehicle or
alternatively - and also by all means preferably -
within the driver's cab 1.
The air-conditioning unit 3 comprises a driver's cab
air treatment device 8 which, in the present case,
comprises two driver's cab blowers 9 and an evaporator
4. Furthermore, a driver's cab filter device (not
shown) is arranged in the driver's cab air treatment
device 8, specifically downstream of the driver's cab
blowers 9 and upstream of the evaporator 4 as viewed in
the flow direction of the sucked-in fresh air. The
further components belonging to the evaporator 4, the
compressor, condenser and expansion valve, of a
refrigeration machine may likewise be accommodated in
the air-conditioning unit 3 or at some other location
in the rail vehicle.
Also situated in the air-conditioning unit 3 is a
machine room air treatment device 11, in which a
machine room fan 6 and a machine room filter device
(recirculation filter) 5 are combined.

Situated in the air—conditioning unit 3 between the
driver's cab air treatment device 8 and the machine
room air treatment device 11 are air guides 13 (shown
only schematically) for already-cooled air flowing in
from the driver's cab 1, which air guides convey a
first part of the air into the driver's cab air
treatment device 8 and a second part of the air into
the machine room air treatment device 11.
An air duct 12 serves to transfer the cooled air into
the machine room 2. A non-return flap 7 is also
installed in the wall 10 which separates the driver's
cab 1 from the machine room 2, or in the air duct 12.
A predefined minimum quantity of fresh air passing from
the outside enters via the roof of the rail vehicle
into the driver's cab air treatment device 8 (first air
guide, illustrated by arrows 21) . The air is sucked in
by means of the driver's cab fans 9 and is subsequently
cooled by the evaporator 4. Furthermore, the air is
also conducted, in order to be cleaned (not shown),
through a driver's cab filter device situated in the
driver's cab air treatment device 8. After the cleaning
and subsequent cooling of the air in the evaporator 4
to a predefined temperature, the air passes downward
out of the driver's cab air treatment device 8 and into
the driver's cab 1 (illustrated by arrows 22).
The cooled air introduced into the driver's cab 1 is
sucked in again by the air-conditioning unit 3 and
branches in the second air guide 13. A first part of
the air is sucked by the driver's cab blower 9 back
into the driver's cab air treatment device 8 and is
cooled once again therein (illustrated by the arrows
23) . This causes the air in the driver's cab 1 to
undergo cooling recirculation. The cooled air emerging
downward from the evaporator 4 into the driver's cab 1
therefore contains components of the fresh air and
components of the recirculated air (illustrated by

arrows 22). A second part of the air, approximately
corresponding to the quantity of constantly supplied
fresh air, is sucked by the machine room blower 6 into
the machine room air treatment device 11, with the
sucked-in air being conducted initially through the
machine room filter 5 (illustrated by arrows 24) . The
purified air then passes through the air duct 12 and
the non-return flap 7 into the substantially air-tight
machine room 2 (illustrated by arrows 25). Air is
introduced continuously into the machine room 2 by
means of the machine room blower 6. This leads to an
elevated air pressure in relation to the environment in
the machine room 2. At most, the air can escape out of
the machine room 2 into the environment through leaks
in the housing of the machine room 2. Therefore, a
small air flow into the machine room 2 is sufficient to
produce the excess pressure. Since said air has already
been introduced as fresh air into the driver's cab 1,
significantly smaller amounts of impurities and
moisture are transferred into the machine room 2 than
would be the case with a direct supply of fresh air
into the machine room 2. If the machine room blower 6
were to fail, the excess pressure in the machine room 2
would dissipate quickly via the air duct 12. To prevent
this, the non-return flap 7 is provided which closes
off the opening between the driver's cab 1 and the
machine room 2. The air entering into the machine room
2 is particularly clean as a result of the multiple
filtering.

We claim:
1. Rail vehicle having a machine room (2) and having
at least one driver's cab (1)/ the rail vehicle
comprising an air-conditioning system (3) provided
for producing an excess pressure in the machine
room (2) and for the air-conditioning of at least
one driver's cab (1),
characterized in that the air-conditioning system
(3) comprises a first air guide (21) for
conducting fresh air into the at least one
driver's cab (1), and a second air guide (13) for
transferring at least a part (24) of the fresh air
(22) introduced into the at least one driver's cab
(1) into the machine room (2).
2. Rail vehicle according to Claim 1, characterized
in that the air-conditioning system (3) comprises
cooling (4) the fresh air as it is introduced into
the at least one driver's cab (1).
3. Rail vehicle according to one of the preceding
claims, characterized in that the air-conditioning
system (3) comprises machine room filtering (5) as
the air is transferred into the machine room (2).
4. Rail vehicle according to one of the preceding
claims, characterized in that the air-conditioning
system (3) comprises at least one machine room air
delivery device (6) for transferring the air into
the machine room (2).
5. Rail vehicle according to one of the preceding
claims, characterized in that the machine room (2)
is of substantially air-tight design, such that as
air is transferred into the machine room (2), an
elevated air pressure in relation to the
environment is generated in the machine room (2).

6. Rail vehicle according to one of the preceding
claims, characterized in that the air-conditioning
system (3) comprises driver's cab filtering as the
fresh air (21, 22) is introduced into the at least
one driver's cab (1).
7. Rail vehicle according to one of the preceding
claims, characterized in that the air-conditioning
system (3) comprises at least one closing device
(7) which prevents the air which has been
transferred into the machine room (2) from flowing
back into the at least one driver's cab (1).
8. Rail vehicle according to one of the preceding
claims, characterized in that the air-conditioning
system (3) comprises a recirculation of a first
part (23) of the fresh air introduced into the at
least one driver's cab (1), and a transfer of a
second part (24) of the fresh air into the machine
room (2).
9. Rail vehicle according to Claim 8, characterized
in that the air-conditioning system (3) also
comprises cooling the first part (23) of the
recirculated fresh air.
10. Rail vehicle according to either of Claims 8 and
9, characterized in that the air-conditioning
system (3) additionally comprises filtering the
first part (23) of the recirculated fresh air.
11. Rail vehicle according to one of the preceding
claims, characterized in that the air-conditioning
system (3) comprises at least one refrigeration
machine, of which at least one evaporator (4)
serves for cooling (4) the fresh air.
12. Method for producing an excess pressure in a
machine room (2) and for the air-conditioning of
at least one driver's cab (1) of a rail vehicle,

characterized in that the method comprises the
introduction of fresh air (21, 22) into the at
least one driver's cab (1) and also the transfer
of at least a part (24) of the fresh air (21, 22)
5 introduced into the at least one driver's cab (1)
into the machine room (2).

To optimize the reliability of electrical and electronic
components situated in a machine room 2 of a rail vehicle
which additionally has at least one driver's cab 1, it is
provided that the rail vehicle be operated with an air-
conditioning system 3 which is provided for producing an
excess pressure in the machine room 2 and for the air-
conditioning of the at least one driver's cab 1. The air-
conditioning system 3 comprises a first air guide 21, 22 for
introducing fresh air into the at least one driver's cab 1
and a second air guide 13 for transferring at least a part 24
of the air 21, 22 introduced into the at least one driver's
cab 1 into the machine room 2.