PlainPatent

CPC technology class · B61

B61F - Rail Vehicle Suspensions

Rail vehicle suspensions, e.g. underframes, bogies or arrangements of wheel axles; rail vehicles for use on tracks of different width; preventing derailing of rail vehicles; wheel guards, obstruction removers or the like for rail vehicles. 797 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

797
US patents granted
#5/9
in B61
9.8%
B61 class share
+11%
5-yr velocity

The verdict

According to USPTO PatentsView, Rail Vehicle Suspensions ranks #482 of 670 CPC technology areas - 797 US patents granted since 2015, with recorded grant volume up 11% over five years.

#482
of 670 CPC technology areas
797
US patents granted, 2015–2025
Kawasaki Jukogyo
leading assignee (93)
+11%
grant velocity, last 5 yrs

How B61F's grant cadence moved

Between 2020–2024, B61F recorded 383 grants versus 345 in 2015–2019 (+11% equal-window velocity). Across complete years, output peaked in 2021 at 92 grants and bottomed in 2015 at 49 (+88% peak-over-trough). Lead assignee Kawasaki Jukogyo Kabushiki Kaisha holds 11.7% of the class ; the top three share 19.6%.

Leaderboard read

B61F concentration, lead at 11.7%

Kawasaki Jukogyo Kabushiki Kaisha leads this historical grant record at 11.7% of B61F - foreign corporation assignees hold 75% of class grants (398 of 530). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
11.7%

93 of 797 grants

Top three share
19.6%

of the class's recorded grants

Lead over #2
61

more grants than Bombardier Transportation GmbH

Where B61F sits inside B61

Among 9 subclasses in B61 (Railways), B61F ranks #5 and holds 9.8% of the parent class's 8,123 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

B61L 2,671 B61D 1,451 B61B 961 B61C 870 B61K 506 B61H 502 B61G 314 B61J 51

Rising assignees active in B61F

Company-wide grant multiples (2022–2024 vs 2019–2021) among assignees with ≥5 patents in this subclass. Growth is company-wide; class patent counts are subclass-specific.

  1. #1 Kawasaki Railcar Manufacturing Co., Ltd. 17x 0 → 17 company-wide · 10 in B61F
  2. #2 Parallel Systems, Inc. 13x 0 → 13 company-wide · 6 in B61F
  3. #3 GET Fabric Ltd 4.00x 2 → 8 company-wide · 5 in B61F
  4. #4 Crrc Tangshan Co., Ltd. 2.33x 6 → 14 company-wide · 11 in B61F
  5. #5 Knorr-bremse Systeme FÜR Schienenfahrzeuge GMBH 1.46x 24 → 35 company-wide · 6 in B61F

B61F grants by year, peak 2021 (92)

US utility-patent grants per year in B61F, 2015–2025 - recent five years are up 11% versus 2015–2019.

20406080100 20152016201720182019202020212022202320242025 34

Who leads B61F?

The 12 most active assignees in Rail Vehicle Suspensions, e.g. Underframes, Bogies OR Arrangements OF Wheel AXLES; Rail Vehicles FOR USE ON Tracks OF Different WIDTH; Preventing Derailing OF Rail VEHICLES; Wheel Guards, Obstruction Removers OR THE Like FOR Rail Vehicles - wider bars mean more grants

patents

What this shows Kawasaki Jukogyo is the most active filer in B61F, holding 93 of the 797 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

Source USPTO PatentsView, granted utility patents As of 2015–2025 grant years
View data table
Top patent holders in CPC subclass B61F
Rank Company Patents in B61F
#1 Kawasaki Jukogyo Kabushiki Kaisha 93
#2 Bombardier Transportation GmbH 32
#3 Crrc Qingdao Sifang Co., Ltd. 31
#4 Amsted Rail Company, Inc. 28
#5 Siemens Mobility GmbH 26
#6 Alstom Transport Technologies 25
#7 Nevis Industries LLC 23
#8 Siemens Mobility Austria GmbH 21
#9 National Steel Car Limited 15
#10 KYB Corporation 14
#11 Siemens AG Österreich 13
#12 Nippon Sharyo, Ltd. 11
#13 Crrc Tangshan Co., Ltd. 11
#14 Kawasaki Railcar Manufacturing Co., Ltd. 10
#15 Firestone Industrial Products Company, LLC 9
#16 Standard CAR Truck Company 9
#17 Mitsubishi Heavy Industries Engineering, Ltd. 8
#18 Electro-Motive Diesel, Inc. 6
#19 Knorr-bremse Systeme FÜR Schienenfahrzeuge GMBH 6
#20 Trinity Rail Group, LLC 6

Footprint here vs. claim strategy

Each dot is a leading B61F assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.

Top 14 B61F assignees by class footprint. Bubble size = patents in B61F. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 051015202530 020406080100 Patents in B61F Avg claims / patent (company-wide) Kawasaki JukogyoBombardier Transportat…Crrc Qingdao SifangAmsted RailSiemens MobilityAlstom TransportNevis IndustriesSiemens Mobility…National Steel CarKybSiemens ÖsterreichNippon SharyoCrrc TangshanKawasaki Railcar…
Top 14 B61F assignees by class footprint. Bubble size = patents in B61F. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near B61F's 797-grant footprint

Nationwide nearest neighbors for B61F (#482 of 670 by volume ; lead share 11.7%) - not the B61 parent-class siblings above.

Nearest by grant volume

B43K 784 F16P 783 F02G 812 B21F 817

Nearest by lead-assignee share

G10H 11.7% B60C 11.7% B65F 11.8% A61C 11.5%

Questions about B61F

Which company holds the most patents in B61F?
Kawasaki Jukogyo Kabushiki Kaisha leads B61F with 93 patents (11.7% of the subclass). By PatentsView assignee type, foreign corporations account for 75% of class grants.
Which B61F assignees grew fastest recently?
Among assignees with ≥5 grants in B61F, Kawasaki Railcar Manufacturing Co., Ltd. shows the highest company-wide grant multiple (17x: 0 grants in 2019–2021 → 17 in 2022–2024) while holding 10 patents in this subclass. Growth is company-wide, not class-only.
How does B61F compare inside parent class B61?
Inside B61 (Railways), B61F ranks #5 of 9 subclasses by grant volume and holds 9.8% of the parent class total. The largest sibling is B61L (2,671 grants).

What to do with this data

B61F in context - here's where to go next.

  • Kawasaki Jukogyo Kabushiki Kaisha leads B61F with 93 grants in this class. See full portfolio
  • B61F ranks #482 of 670 by grant volume among all tracked CPC technology areas. See the ranking
  • Inside parent class B61, the largest sibling subclass is B61L with 2,671 grants. Explore B61L

Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.

Methodology - B61F figures are USPTO PatentsView granted-utility totals for this subclass (797 grants in the tracked window).

Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.