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CPC technology class · B61

B61K - Auxiliary Equipment Specially Adapted FOR Railways

Auxiliary equipment specially adapted for railways, not otherwise provided for. 506 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

506
US patents granted
B61
Parent CPC class
20
Active assignees
+40%
5-yr velocity

The verdict

Auxiliary Equipment Specially Adapted FOR Railways ranks #541 of 670 CPC technology areas - 506 US patents granted since 2015, with filing up 40% over five years.

#541
of 670 CPC technology areas
506
US patents granted, 2015–2025
Bnsf Railway
leading assignee (27)
+40%
filing velocity, last 5 yrs
Top assignee: BNSF Railway Company (27 patents)

CPC subclass B61K - AUXILIARY EQUIPMENT SPECIALLY ADAPTED FOR RAILWAYS, NOT OTHERWISE PROVIDED FOR - covers 506 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class B61 (RAILWAYS). See our CPC classification guide for how the system works.

The competitive landscape in B61K is shaped by 20 distinct companies actively filing in this space. BNSF Railway Company leads with 27 patents, followed by Tetra Tech, Inc. at 20 grants and Amsted Rail Company, Inc. at 13.

Filing activity in B61K is up 40% over the past five years versus 2015-2019, a sharp acceleration suggesting an emerging or fast-moving technology area. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is B61K innovation accelerating?

US utility-patent grants per year in B61K, 2015–2025 - recent five years are up 40% versus 2015–2019.

20304050607080 20152016201720182019202020212022202320242025 41

Who leads B61K?

The 12 most active assignees in AUXILIARY EQUIPMENT SPECIALLY ADAPTED FOR RAILWAYS, NOT OTHERWISE PROVIDED FOR - wider bars mean more grants

patents

What this shows Bnsf Railway is the most active filer in B61K, holding 27 of the 506 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 B61K
Rank Company Patents in B61K
#1 BNSF Railway Company 27
#2 Tetra Tech, Inc. 20
#3 Amsted Rail Company, Inc. 13
#4 Ensco, Inc. 12
#5 International Electronic Machines Corp. 10
#6 L.b. Foster Rail Technologies, Inc. 10
#7 Progress Rail Services Corporation 8
#8 GE Global Sourcing Llc 7
#9 Knorr-bremse Systeme Für Schienenfahrzeuge Gmbh 6
#10 Whitmore Manufacturing, Llc 6
#11 Bombardier Transportation Gmbh 5
#12 Smartdrive Systems, Inc. 5
#13 Plasser & Theurer Export Von Bahnbaumaschinen Gesellschaft M.b.h. 5
#14 Harsco Technologies Llc 5
#15 Plasser & Theurer Export Von Bahnbaumaschinen Gmbh 5
#16 Sperry Rail, Inc. 5
#17 Georgetown RAIL Equipment Company 4
#18 Precision Rail And Mfg., Inc. 4
#19 New York Air Brake Llc 3
#20 CRRC Qingdao Sifang Co., Ltd. 3

About This Class

CPC subclass B61K belongs to class B61.

506 patents were granted in this class between 2015 and 2025.

20 companies actively patent in this space.

Classification System

Cooperative Patent Classification (CPC) is a hierarchical patent classification system used by the USPTO and EPO.

← All Technology Classes Technology Rankings →

Footprint here vs. claim strategy

Each dot is a leading B61K 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 B61K assignees by class footprint. Bubble size = patents in B61K. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Top 14 B61K assignees by class footprint. Bubble size = patents in B61K. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 510152025 051015202530 Patents in B61K Avg claims / patent (company-wide) Bnsf RailwayTetra TechAmsted RailEnscoInternational MachinesL B Foster RailProgress Rail ServicesGe Global SourcingKnorr-bremse Systeme…Whitmore ManufacturingBombardier Transporta…Smartdrive SystemsPlasser & Theurer Exp…Harsco
Top 14 B61K assignees by class footprint. Bubble size = patents in B61K. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class B61K?
CPC subclass B61K covers AUXILIARY EQUIPMENT SPECIALLY ADAPTED FOR RAILWAYS, NOT OTHERWISE PROVIDED FOR. It belongs to CPC class B61 (RAILWAYS), with 506 US utility patents granted since 2015.
How many patents have been filed in B61K?
506 US utility patents were granted in CPC subclass B61K between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in B61K?
BNSF Railway Company leads B61K with 27 patents, making it the most active assignee in this technology area.
How is patent data for B61K collected?
Patent data comes from USPTO PatentsView, a public research dataset maintained by the United States Patent and Trademark Office. It covers all US granted utility patents and assigns CPC codes based on the technology described in each patent.
What is the difference between CPC class and subclass?
A CPC class (e.g., B61) is a broad technology category. Subclasses like B61K provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from USPTO PatentsView - official U.S. government patent data. See our methodology for computation details. Retrieved and formatted by PlainPatent Editorial

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.