May/June 2024 - 19

115
All trains UP Tangara UP
110
105
100
95
90
Dec-20
Jan-21
Feb-21
Mar-21
FIGURE 4. Tangara trains represent nearly all high vibration events recorded.
Image: Briony Croft presentation
Train type Total cars New WILD flags in
year (% of cars)
Waratah 866
Tangara
447
60 (7%)
476 (106%)
Cleared
WILD flags
56
504
Average days
to clear
91
44
FIGURE 5. Wheel impact load detector measurements for both car types.
Image: Briony Croft presentation
" This made it clear that wheel flats
were driving the difference in vibration
events, " Croft said.
Maintenance records showed that
there was no marked difference in how
or where the car types were maintained
-in fact, wheel flats were corrected
faster, on average, on the Tangara cars
versus the Waratahs. This is where the
only fundamental design difference
between the two cars plays a role. The
Tangara cars use DC traction and friction
braking at low speeds while the
Waratah cars have more modern AC
traction systems and use dynamic braking
at all speeds. Wheel flats generated
as a function of this design difference
contributed to significant differences in
vibrations. This shows the importance
of vehicle design or selection when
you're mitigating vibrations.
" The general assumption was that
vibration levels for the two car types
should be the same since they're simply
a different generation of the same car, "
Croft said.
The Sydney case study illustrates one
of the less-obvious ways in which car
design can affect a transit system. It also
illustrates the fact the optimization of
the vehicle/track dynamic doesn't necessarily
end once a vehicle is designed
and delivered.
Wheel/rail profile interaction and
optimization, like vehicle/track interaction,
has a profound influence on
the kinds of characteristics and performance
specifications that transit systems
and car builders target. Wheel and rail
profile matching can be part of the new
car design/procurement process but it
can also be part of the maintenance/
operational phase of car deployment.
As Siemens' McClain detailed, vehicle/track
interaction (and optimization)
is a critical component of delivering
a well-designed vehicle. Wheel/rail
interaction takes that optimization a
step further, to a more granular level.
Transit properties commission wheel/
rail studies for many reasons. The goal
may be to improve curve performance
swhhsr.com
STACYWITBECK | HERZOG
For more information, visit
www.MassTransitmag.com/10065974
MAY/JUNE 2024 | MassTransitmag.com 19
2406MASS_Stacy Witbeck-REV.indd 1
5/1/24 1:13 P
Vertical vibration train passby Lmax,S
(dbV re 1e-9 m/s)

http://www.swhhsr.com http://www.MassTransitmag.com/10065974 http://www.MassTransitmag.com

May/June 2024

Table of Contents for the Digital Edition of May/June 2024

Editor’s Notebook
People & Places
Rep. Blumenauer led a movement of connection and choice
2024 Trends in Passenger Rail
Vehicle Design: Managing Noise and Vibration from the Ground Up
Transit Cybersecurity and Threat and Vulnerability Assessments, Public Transit Risk Assessment Methodology
Government of Ontario’s One Fare program sees early success
CUTRIC continues steps towards cleaner transit and community
Products
May/June 2024 - 1
May/June 2024 - 2
May/June 2024 - 3
May/June 2024 - 4
May/June 2024 - 5
May/June 2024 - Editor’s Notebook
May/June 2024 - 7
May/June 2024 - People & Places
May/June 2024 - 9
May/June 2024 - Rep. Blumenauer led a movement of connection and choice
May/June 2024 - 11
May/June 2024 - 2024 Trends in Passenger Rail
May/June 2024 - 13
May/June 2024 - 14
May/June 2024 - 15
May/June 2024 - Vehicle Design: Managing Noise and Vibration from the Ground Up
May/June 2024 - 17
May/June 2024 - 18
May/June 2024 - 19
May/June 2024 - 20
May/June 2024 - 21
May/June 2024 - Transit Cybersecurity and Threat and Vulnerability Assessments, Public Transit Risk Assessment Methodology
May/June 2024 - 23
May/June 2024 - 24
May/June 2024 - 25
May/June 2024 - Government of Ontario’s One Fare program sees early success
May/June 2024 - 27
May/June 2024 - 28
May/June 2024 - 29
May/June 2024 - CUTRIC continues steps towards cleaner transit and community
May/June 2024 - 31
May/June 2024 - 32
May/June 2024 - Products
May/June 2024 - 34
May/June 2024 - 35
May/June 2024 - 36
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