B61L 3/221
Using track circuits
Official title: {using track circuits}
B61L3/221 (Using track circuits) appears on 50 US grants and 35 published applications in this corpus.
Search patents in B61L- Granted patents
- 50
- Published applications
- 35
- Assignees
- 27
- Inventors
- 82
- Latest grant
- 7 Jul 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 2 | 0 |
| 1978 | 0 | 0 |
| 1979 | 0 | 0 |
| 1980 | 3 | 0 |
| 1981 | 1 | 0 |
| 1982 | 0 | 0 |
| 1983 | 1 | 0 |
| 1984 | 2 | 0 |
| 1985 | 0 | 0 |
| 1986 | 1 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 1 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 1 | 0 |
| 1994 | 1 | 0 |
| 1995 | 1 | 0 |
| 1996 | 1 | 0 |
| 1997 | 0 | 0 |
| 1998 | 1 | 0 |
| 1999 | 1 | 0 |
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 1 | 1 |
| 2004 | 0 | 0 |
| 2005 | 0 | 3 |
| 2006 | 2 | 0 |
| 2007 | 0 | 0 |
| 2008 | 1 | 0 |
| 2009 | 0 | 1 |
| 2010 | 0 | 3 |
| 2011 | 0 | 1 |
| 2012 | 2 | 1 |
| 2013 | 1 | 3 |
| 2014 | 2 | 2 |
| 2015 | 2 | 0 |
| 2016 | 2 | 1 |
| 2017 | 1 | 0 |
| 2018 | 0 | 2 |
| 2019 | 1 | 1 |
| 2020 | 0 | 0 |
| 2021 | 3 | 4 |
| 2022 | 3 | 4 |
| 2023 | 2 | 2 |
| 2024 | 3 | 2 |
| 2025 | 1 | 2 |
| 2026 | 3 | 2 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- System and method for virtual block stick circuits7 Jul 2026US 12,673,707 B2BNSF Railway Company
- Railroad virtual track block system16 Jun 2026US 12,654,753 B2BNSF Railway Company
- Railway detection system, railway infrastructure and method for detecting the presence of a railway vehicle2 Jun 2026US 12,643,583 B2
- System and method for virtual block operational status control with long block time delay23 Dec 2025US 12,503,145 B2BNSF Railway Company
- System and method for virtual block stick circuits15 Oct 2024US 12,116,028 B2BNSF Railway Company
- Railroad virtual track block system8 Oct 2026US 2026/0307691 A1BNSF Railway Company
- System and method for virtual block operational status control with long block time delay30 Apr 2026US 2026/0116439 A1BNSF Railway Company
- Device for testing cab signaling system and a method thereof17 Jul 2025US 2025/0229813 A1
- System and method for virtual block stick circuits30 Jan 2025US 2025/0033679 A1BNSF Railway Company
- Railway detection system, railway infrastructure and method for detecting the presence of a railway vehicle9 May 2024US 2024/0149931 A1ALSTOM Holdings
Most cited
By later US patents
- Integrated cab signal rail navigation system98US 5,995,881 AWestinghouse Air Brake Company · 1999
- Fixed data transmission system for controlling train movement72US 5,452,870 AHarmon Industries, Inc. · 1995
- Train control system integrating dynamic and fixed data64US 5,340,062 AHarmon Industries, Inc. · 1994
- Cab signal sensor with noise suppression33US 5,586,736 AHarmon Industries, Inc. · 1996
- Systems and method for communicating data in a railroad system26US 8,264,330 B2General Electric Company · 2012