PROCEEDINGS of the23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

Passenger’s Train Soundscape: Identification of Activities
Nurul HIDAYAH1; Gumilang Paramarta SANISKARA2; Nurfitirana MUHARAMI3; Keysha
Wellviestu ZAKRI4; Anugrah Sabdono SUDARSONO5; Sugeng Joko SARWONO6
1,2,3,4,5,6

Laboratory of Building Physics and Acoustics, Institut Teknologi Bandung, Indonesia

ABSTRACT
Passenger’s train is an environment where people are exposed by mechanical sound and the sound of humanactivity. The passengers need to be in the same acoustic environment for a period of time, so a comfortableenvironment is a necessity. Soundscape intervention can be applied in this case with the consideration ofpassenger’s activity. This study tries to identify the activities in a passenger’s train with 9 hours (07:20-16:20)
journey.
There are several activities identified in the train: sleeping, eating, going to the toilet, and using mobile phone.
In general, when the passengers are not sleeping, they are using mobile phone. The passenger tends to sleep
during three periods of time. The eating activity happens once after the first sleeping period. The passenger’s
going to the toilet twice during the journey. First, after two hours of journey and after 5 hours of journey. Thestudy has identified the passenger’s activity during nine hours train journey. The result of this study can bebeneficial to design acoustic environment scenario which considers the different activity.
Keywords: Sound, Insulation, Transmission

1. INTRODUCTION
Since becoming one of the most advanced and developed transportation [1], many people choose
the train as their transportation. As train’s passengers, they are exposed by mechanical sound andhuman activity sound during the journey [2]. Train’s passengers have to stay on the train and perceive
same acoustic environment for a period of time during the journey. Since they cannot change theacoustic environment when it feels uncomfortable, acoustic comfort became one of the important
aspects to be considered.
Train in Indonesia classified into two different groups, local train and inter-city train. Most ofinter-city trains have more than 8 hours of travel time [3]. The object of this study is long journey
train with 9 hours (07:20 – 16:20) travel time. There are several activities on the train during the travel
time and every activity needs different acoustic environment. The aim of this study is identifying thedominant activity per period of time during the journey. Different activities also give different
perception to the acoustic environment. The results from identification can be used to determine thesuitable soundscape intervention will be applied.
Previous study had been done on the train with 3 of hours travel time [2]. The result of the study
showed monotonous activities from the departure until the arrival so the same acoustical environment
could be applied during the travel time.

2. LODAYA TRAIN
The train will be identified in this study is Lodaya train which classified as inter-city train with 8hours and 41 minutes travel time. Lodaya train has average velocity at 60-100 kilometers per hour.
Lodaya train is mass railway transportation provided by Indonesian Railways Company (PT KAI)
1

nurulhidayah1610@yahoo.com
gumilangps@gmail.com
3
nmuharami@gmail.com
4
keyshawz@gmail.com
5
anugrah@tf.itb.ac.id6
jsarwono@tf.itb.ac.id22509

purposely serving passengers from Bandung to Solo, and vice versa .
The train usually leaves Bandung Hall Station at 07:20 in the morning and at 18:55 at night.
Meanwhile, the train leaves from Solo Balapan Station at 07:10 in the morning and at 19:10 at night.
It provides 2 classes of train, executive class and economy class. This study is foc used on economy
class of Lodaya train with departure time 07:20 from Bandung Station and have 80 seat capacity [2] .

Figure 1 – Economy Class Passenger Train of Lodaya [4]3. METHODS
The analysis was conducted by in-situ measurement. In-situ measurement was performed by direct
observing on the train and writing down passenger’s activities every 30 minutes during the journey.
The data of observing on the train provided information about dominant passenger’s activities every
30 minutes.
Besides observing, an objective measurement was also done to get objectives parameter. The
objective evaluation was done by sound recording inside the train during the journey. Thus, the data
represent whole condition of the journey. The measurement was done in the passenger’s train using
binaural recording during the journey. In addition to binaural recording, the devices used to obtainobjective parameters are Zoom H2n Handy Recorder and Zoom H3-VR Handy Recorder. Thismeasurement takes place in the middle seat of the train’s cart that could represent the whole acoustic
environment on the passenger train.
Objective measurement would provide several parameters such as sound pressure level, L eq, L10 ,L90 , and L50 . Background noise on the train is represented by L 90 and eventual sound is represented by
L10 . This eventual sound is mostly caused by passenger activities. Thus, there was a correlation
between passenger’s activities and sound pressure level on the train.
The result from objective measurement will be compared with the result of observing passenger’sactivities every 30 minutes during the journey. From these measurements, the basic for designingsuitable acoustic environment on the long-distance train can be obtained. The proper acoustic design
based on the passenger’s activities will help passengers feel comfort although it’s a long journey.

4. RESULT
4.1 Sound Pressure Level Analysis
Objective measurement was performed to collect sound level data during the journey. In this study,sound level data was collected for 8 hours and 41 minutes and calculated for every 30 minutes to get
Leq , L10, L50, and L90 data as shown in Figure 2.

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Figure 2 – Sound Pressure Level in the Lodaya Train
Figure 2 shows the value of L eq , L10, L50 , and L90 are fluctuating during the journey. Generally, thevalue of LA eq in this train is around 64.5 dBA. L 90 value indicates background noise level in thepassenger’s train which comes from train movement. L 90 value decreases at 09:21 – 10:20, 10:51 –11:21, 12:51 – 13:20, and 13:51 – 13:50 because of the train stopped at several stations. Nonetheless,
L90 value increases at last 11 minutes of the journey because of the other sound sources beside noisefrom train movement as background noise.
Table 1 – Range Value of Sound Pressure Level
Maximum Value, dBA

Minimum Value, dBARange, dBA

Leq

68.4

57.6

10.8

L10

74.0

60.3

13.7

L50

65.7

57.3

8.4

L90

61.9

52.4

9.5

L10 value indicates incidental sound level in the passenger’s train and it increases at 08:51 – 09:20,09:51 – 10:20, 11:21 – 11:50, 12:51 – 13:20, and 13:51 – 14:20. Table 1 shows the value of L 10 has
the highest range than the other value. It indicates there are variated incidental sound with variatedlevel during the journey. Most of incidental sounds came from passenger’s activities in the train. There
are a wide difference between L 10 and L90 at 07:21 – 07:50, 09:51 – 10:20, 10:51 – 11:21, 11:21 –11:50, 12:51 – 13:20, and 14:21 – 14:50 more than the average difference. Incidental sounds with highsound pressure level appeared at those time.
The value of Leq has similar fluctuation with the value of L 10 and increases at the same time. The
trend of the value could be seen in Figure 2 but the sound sources could not be identified. Consequently,
further analysis must be done to identify dominant sound sources related to the sound levelmeasurement. Dominant sound sources could be identified by analyzing spectral sound levelmeasurement.
4.2 Spectral Sound Level Analysis
Figure 3 showed the correlation between sound pressure level, frequency and measurement time.
Dominant frequency of measured sound inside the train is low frequency between 100 Hz – 315 Hz
and constantly measured during the journey The result of sound pressure level measurement showed
fluctuated value but still stable because the increment and decrement were not too high. The increasing
sound pressure level appeared at 09:51 – 12:20. The increment occurred at higher frequency up to1000 Hz. The increasing sound pressure level also occurred at lower frequency at 09:51 – 12:20 and11:51 – 12:50. The increment occurred at 63 Hz. The increasing sound pressure level at several range

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frequency was caused by incidental sound sources. Otherwise, there was a decreasing sound pressurelevel occurred at 09:21 – 09:50.

Figure 3 – Spectral Sound Level of Lodaya Train
Dominant frequency values can be used to identify dominant sound sources in the train. The low
frequency as dominant frequency explained that the dominant sound source is mechanical sound.
Mechanical sound could come from friction between the wheel and the rail causing vibration that
propagates through the structure of the train [5]. Mechanical sound would appear along the journey.
The decreasing sound pressure level at 09:21 – 09:50 indicates mechanical sound from train
movement disappeared due to train stopped at the station for a long time. On the other hand, theincreasing sound pressure level at several periods of time indicates occurrance incidental sound frompassenger’s activity. The sound from activities has frequency characteristic up to 1000 Hz.
Passenger’s activities with frequency up to 1000 Hz is conversation. The result of objective
measurement must be validated by in-situ measurement of activities.
In-situ measurement of activities was done by writing down passenger’s activities every 30 minutes
during the journey. The data shows there were four dominant passenger’s activities on the train. The
dominant passenger’s activities were conversation, eating, sleeping, and using mobile phone.
4.3 Identification of Passengers Activities
There were different dominant activities for every period. There were conversation, eating,sleeping, and using mobile phone. Conversation activities occurred 5 periods during the journey.
Eating activities also occurred 5 periods during the journey but at different periods. Sleeping andUsing mobile phone occurred at 4 periods of time.

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Time

07:21- 07:51- 08:21- 08:51- 09:21- 09:51- 10:21- 10:51- 11:21- 11:51- 12:21- 12:51- 13:21- 13:51- 14:21- 14:51- 15:21- 15:5107:50 08:20 08:50 09:20 09:50 10:20 10:50 11:21 11:50 12:20 12:50 13:20 13:50 14:20 14:50 15:20 15:50 16:11

Activities
Conversation
EatingSleeping
Using Mobile Phone

Figure 4 - Dominant Passenger Activities
The dominant activities are divided into two different groups of activities with different appearance
period. As shown in figure 4 conversation and using mobile phone appeared as dominant activities atmost of the same period. Those activities appeared at the beginning of the journey, in the middle ofthe journey and the end of the journey. Eating and sleeping as the other dominant activities also
appeared at the same period. The figure 4 showed the passengers tend to eat or sleep when they are
not chatting or using mobile phone.
4.4

Correlation between Objective Measurement and Identification of PassengerActivities
Sound pressure level measurement result is consistent with the identification of passenger’sactivity result. Sound pressure level measurement result showed Leq value is fluctuating and increasing
at 09:51 and identification of passenger’s activity result showed conversation activity showed at thesame period. The data was also strengthened by spectral sound level analysis result. The soundpressure level increased at mid and high frequency up to 1000 Hz at those periods. Conversation has
a frequency characteristic between 250 Hz – 4000 Hz [6]. Accordingly, conversation is correlated toLeq with correlation coefficient 0.3.
Some improvements would be necessary to achieve acoustic comfort in the passenger’s train. Dueto different dominant activities for every period during the journey, it needs different acousticenvironment. Thus, suitable soundscape intervention could be applied differently for every period
during the journey.

5. CONCLUSIONS
The value of Leq L10 , L50, and L90 were fluctuating during the journey and the value of LA eq in thistrain during the journey is around 64.5 dBA. Fluctuation of L eq’s value same as fluctuation of L 10 ’svalue because of incidental sounds. The increasing sound pressure level was caused by passenger ’sconversation. It is shown by the value of the correlation coefficient between L eq and conversation
appearance frequency. It is also strengthened by spectral analysis result that shows increment soundpressure level at high frequency up to 1000 Hz. Identification of passenger ’s activity result explains
there were four dominant passenger’s activities. There were conversation, eating, sleeping, and using
mobile phone. Those dominant activities appeared at different periods of time. Thus, soundscapeintervention should be applied differently for every period during the journey.

ACKNOWLEDGEMENT
This research was supported by a grant from National Center for Sustainable Transportat ion
Technology and funded by the Ministry of Research, Technology, and Higher Education of theRepublic of Indonesia.

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