The IEEE 1473-L Train Network Protocol
Frequently Asked Questions
( )

Updated: 27 Feb 2005

What is IEEE 1473-L? What about Wayside Applications?
How do I obtain a copy of the standard? Which Railcar Builders use LonWorks?

Where is it used?

Who makes subsystems & Development Tools?
What is LonMark? Where can I find Specifiers & Designers?
Why do end-users mandate LonMark? Where can I obtain Training?
How can I ensure my Network is Open? How can I get answers to Technical Questions?
What about Safety Critical Applications? 

What is IEEE 1473-L?

IEEE 1473-L is the world's most widely used rail car network. Based upon LonWorks IEEE-1473-L is the same control network protocol used on thousands of rail cars from UK to China and from coast-to-coast in North America. LonWorks is also the AAR's S-4200  train network standard for next generation Electronically Controlled Pneumatic Brakes. (See also: where used)

LonWorks became an IEEE standard in 1999 after becoming an ANSI/EIA standard under EIA 709.1. The availability of an Open Reference Implementation now allows anyone to port the protocol at no cost to any microprocessor. (Note: Prior to 1999 LonWorks was considered a proprietary protocol.) Today, most agree that LonWorks is an open protocol. 

IEEE-1473-L based systems that conform to LonMark Guidelines, by definition, have fully open interfaces. Open interfaces are important to transit operators because rail cars may be expected to last 30-40 years. When spares are needed but the original vendor is no longer in business or wants to support its product, the benefits to open interfaces become clear. Conformance to LonWorks and LonMark Guidelines greatly reduces the risk of being tethered to a single supplier by allowing others to build compatible systems.
(See also: Ensuring an IEEE-1473-L network is open.)

LonWorks based networks have been deployed by >4,000 OEMs in >30 million nodes across multiple industries. As a result highly cost-effective, multi-sourced components are widely available. Other train network systems may require entire circuit boards for each node but most LonWorks networks today are implemented using low-cost integrated circuits from Toshiba and Cypress that can be embedded into existing vehicle and wayside systems. 

Unlike other protocols, LonWorks provides services at all seven layers of the ISO OSI 7-Layer Model. Its robust networking layer (Layer 3) combined with built-in authentication make it easy to build secure systems that can also be seamlessly integrated with Internet Protocol (IP), Ethernet (IEEE 802.3),  WiFi (IEEE-802.11)  using ANSI/EIA 852.

With proper application of these open standards it is now possible to architect seamless end-to-end communications from an individual rail car sensor all the way to a rail control center, Rail ITS, & beyond....  

Today, LonWorks systems that conform to LonMark Guidelines are starting to be integrated with new open XML and SOAP protocols. As a result  they are expected to be highly compatible with the US Department of Transportation's National Architecture for Intelligent Transportation Systems, NTCIP and newly emerging TCIP2 standards.

For more on IEEE-1473-L and LonWorks see:




Related Links

White Papers



2. How do I obtain a copy of the IEEE 1473 Standard?  

The standard can be purchased from IEEE via the IEEE Standards on-line Store. 1473 is now coming up for renewal and Working group 1 will soon be meeting to decide what if any changes should be made to this protocol.

IEEE-1473-L is one of two protocols defined in IEEE Std. 1473-1999, and specified by the Rail Transit Vehicle Interface Standards Committee's WG1. IEEE 1473-L defines ANSI 709.1 (LonWorks) over ANSI 709.3 Free Topology physical layer. 

More information about IEEE-1473-T can be obtained by clicking on the WG1 link.


3. Where is IEEE-1473-L used?

While LonWorks has been used for "helm to propeller control" for the Navy's USS Rushmore and to demonstrate a fully deterministic "primary flight control" for the US Army's Apache helicopter, every major rail car supplier has built rail cars using IEEE 1473-L. (See Table below.) 

For wayside, LonWorks is deployed (or being deployed) in heavy rail systems in Germany and France, light rail systems in Seattle and San Diego and automated people movers in San Francisco. For safety-critical wayside applications LonWorks is used in Safetran's S3 Link radios, Grade Crossing Predictors and its new Geo vital Interlocking.  

In 2001, the world's longest subway system, NYC Transit, demonstrated interoperability between trainlined LonWorks cars from Bombardier and Kawasaki. This successful interoperability demonstration was possible because NYCT's required its rail cars conform to open standards and also LonMark Interoperability Guidelines

NYCT,  was the first to mandate IEEE-1473-L and conformance to LonMark guidelines in its vehicle specifications. After carefully evaluating several alternatives, NYCT selected LonWorks because of its open architecture, service-proven technology and worldwide support. 

Below is a partial list of locations where LonWorks is known to be used in Transportation. 

Please contact us if you know of additional links:

Heavy Rail  Vehicles

Light Rail




Wayside Applications  
Traffic and Intelligent Transportation Systems 

New York, NY
New York City Transit
Over 1000 rail cars 
Bombardier R142
Kawasaki R142A & R143
Alstom R160

IEEE 1473-L networks/trainline

-Diagnostics monitoring 
-Siemens CBTC interface

Chicago, IL

706 Next Generation 1000 Series subway  cars. LonWorks:  Doors, Propulsion, Passenger Information, Train Operator Touch Screen, IEEE 802.11.
Spec Section 15 

Vehicle Network

Trainline T1 Mux

Helsinki, Finland 
Metro (pdf). 

San Francisco, CA 
GE Nippon Signal  Safety-critical Train Control trainline overlay using LonWorks Powerline Technology
Safety-critical brake watchdog monitor  

Washington, DC
1000 series rehab
5000 series - CAF
6000 series -Alstom
Diagnostic systems 


San Francisco, CA
Muni Railway
Breda Trainlined Passenger Information signs by Trans-Lite

San Jose, CA
Valley Transit Authority
Kinkisharyo -
Diagnostic Systems by
Rail Transit Consultants

Philadelphia, PA
Bombardier CBTC Radio system monitor

Los Angeles, CA
Breda P2050
US&S cab signal system
Pasadena Gold Line 
AnsaldoBreda P2250
Vehicle monitoring  Door Systems 

Minneapolis, MN
Hiawatha Transit  LRV

Phoenix, AZ
Kinkisharyo LRVs using GeoFocus IEEE-1473-L Vehicle Network 

Kuala Lumpur, Malaysia
Bombardier -  Propulsions, HVAC, Brakes, Health Monitor by Quester Tangent

Acela Express -
Many subsystems including
Train Diagnostics
Advanced Civil Speed Enforcement System

Chicago Metra
Nippon Sharyo -
Passenger Information System by GeoFocus  

New York, NY Metro North Commuter Rail
 Monitoring System - Peerless

Long Island Railroad
M7 Bombardier
US&S MicroCab Signal System

Newark, NJ 
NJ Transit
10  subsystems on
Comet V's  
by Alstom and
TCN  locos by Bombardier
US&S MicroCab Signal System

VIA Rail

Train Network Communications
(1.2 MByte PPT Presentation) 

Japan Railway East
Monorail Station Platform Doors.

Sydney, Australia
Commuter Rail
Door Control, Security

Association of American Railroads
Electronic Braking
 S4200 Standard 
 Knorr  & Wabtec. Reduces braking distance up to 70%

Virgin Atlantic  Passenger Rail Cars by Bombardier

Southwest Trains  "Desiro" by Siemens & SA ViewCom

Canadian National Railroad

Propulsion Pack and Braking Control

Ministry of Railways
2,000 Passenger rail cars ( HVAC, Doors Power Supply, etc) Plans for ECP Brakes
Shanghai Express on T21/22

Federal Railroads
Passenger Stations
Fire Alarms, Smoke Dampers, Electric  Meters, Emergency Lighting, Sprinklers, HVAC,  Elevators Escalators, Moving Walkways -  TAC

Swiss National Railroads
Passenger Information by Netcon

New York, NY
JFK AirTrain
Vehicle Monitoring Systems by
Quester Tangent

Seattle, WA
ata radio for  Bombardier CBTC

San Francisco, CA - SFO Airport 
Andrew data radio for  Bombardier CBTC

Vancouver SkyTrain
Diagnostic & Monitoring Systems Quester Tangent

Mark II Bombardier
Station Wayside security Notifier


Intelligent Transportation Systems
Tollgates, tunnel ventilation & gas monitoring

San Diego, CA
SD LRV Tunnel control and monitoring by HSQ and  Control by Light

Seattle, WA Central Link
Light Rail
Wayside systems including power substations, ticket vending, fire alarms,  radio fiber switches, UPS, elevators and escalators, door trackway and intrusion, HVAC
Transit Signal Priority
1300  King County transit buses for  passenger counting & route info using  AAR  RF-ID tags to Automobile Traffic Controllers  interconnected via  LonWorks.

LonWorks based remote monitoring and control of rail heaters for track switches by DAI-DAN Co., Ltd. 

Train Station 
Remote lighting and heater controls over powerline

Charles de Gaulle Etoille Station
Platform Doors by Faiveley
for RATP
Meteor Line  

McCain Traffic Supply

Open Interface Traffic Controllers Smart Transit Vehicle Priority System



Spartan Motors
Fire Trucks

Marathon Coach
High end RV using 33 nodes for engine control & diagnostics, lighting a/c door control, generators

Apache Helicopter  Demo
 Primary Flight Control


USS Rushmore
Redundant control from helm-propeller


4. What is LonMark?

LonMark International
is the 300+ member group of end-users, developers, consultants and system integrators who have agreed to promote, market and specify the use of open, interoperable systems based upon LonWorks. LonMark is a not for profit organization.

Increasingly, transit properties are beginning to mandate conformance to LonMark guidelines because it effectively requires subsystem interfaces to be fully defined and exposed. Exposing key subsystem interfaces makes it easier to specify, procure, operate and maintain cost effective electronic systems and harder for end users to be tethered to single suppliers.  

LonMark Profiles for rail transit subsystems are "object representations" of vehicle and wayside subsystems such as GPS locators, propulsion controllers, door system interfaces, sign systems, HVAC, etc. By mandating IEEE-1473-L systems conform to LonMark Functional Profiles and interoperability guidelines both a transit property and a car builder will have a system with open interfaces and thus minimizing the traditional risks associated with proprietary systems and interfaces

While LonMark Functional Profiles are copyrighted documents anyone may use and reference them. However, membership in the LonMark Association is required to participate in the development of new LonMark Profiles.

Key to developing open, interoperable systems using LonWorks is conformance to LonMark Interoperability Guidelines.

 These include the use of LonMark Profiles and the use of  Standard Network Variable Types.  


Many LonMark Members are also members of IEEE RTVISC and its WG 9 is now working with LonMark to develop new LonMark Profiles for rail cars.

LonMark Membership for end users, transit properties, consultants, and other non-profit associations, is $250/year. Manufacturers, suppliers and others have other membership categories. To join simply download and complete this membership application. 


5. Why do End Users Mandate LonMark Guidelines?

While LonWorks is a powerful and flexible control network protocol it is still possible to build closed proprietary systems if network interfaces are not fully exposed and designs do not conform to open LonMark Interoperability Guidelines.  For this reason, increasingly, end-users benefiting from IEEE-1473-L are also requiring conformance to LonMark Interoperability Guidelines to help them avoid being tethered to propriety systems. This critical need for open interface standards is more fully described by the former chair of the Rail Transit Vehicle Interface Standards Committee, Tom McGean in his APTA paper "Oh What a Tangled Web We Weave."
Transit Organization

LonMark Member

LonWorks/LonMark Projects
MTA NYC Transit
New York City
722 mile heavy rail subway
6,000 subway cars
469 passenger stations
Yes All new subway cars
R142 Bombardier
R142A Kawasaki
R143 Kawasaki
R160 Alstom
Chicago Transit Authority
222 mile heavy rail subway
1200 subway cars
144 passenger stations
All next generation subway cars
beginning with new 1000 Series
Washington, DC
100 mile heavy rail subway
6000 Series subway cars
5000 Series subway cars
1000 Series HVAC rehab
New Jersey Transit
Commuter Rail System
Yes Alstom Comet Cars - commuter rail
Central Link Light Rail
Seattle's Sound Transit
Light Rail System
Wayside Communications Backbone
Santa Clara Valley Transit
Light Rail System in San Jose, CA
Yes Kinkisharyo Light Rail Vehicles
Los Angeles
Light Rail System for Pasadena Gold Line 
AnsaldoBreda P2550 LRVs


6. Which Railcar Manufacturers use IEEE-1473-L?

Passenger Rail Car Outlook 2001





Alstom Dr. Marcos Albuquerque  Yes New Jersey Transit Comet V
MTA Long Island Railroad M7
WMATA 6000 series
NYCT R-160
Bombardier Christian Girard Yes Amtrak Acela Express 
Kuala Lumpur
NYC AirTrain
MTA NYC Transit R142
MTA Long Island Railroad M 7 
Vancouver SkyTrain Mark II ALRT
AnsaldoBreda SF Muni LRVs - Passenger Information Signs
LAC MTA - Pasadena Gold Line P2250 LRV's 
CAF Washington Metro 5000 Series
Kawasaki NYC Transit - R142A, R143
Kinkisharyo Santa Clara Valley Light Rail - Diagnostic Systems

Yes UK Desiro Southwest Trains
 subsystems by SA Viewcom;
Many LonWorks building systems
Sumitomo/Nippon Sharyo Chicago Metra, Commuter Rail - Pa
Pasenger Information and locating systems
by GeoFocus


7. Who makes IEEE-1473-L Subsystems, &  Components?





Alstom E. Fargues Yes Computers, displays, propulsion
Bach Simpson Event Recorders
Control By Light Rollin Hughes Yes Ultra-reliable, fault-tolerant, tamper-proof, fiber-based sense and control networks. Products conform to SAE AS-5370 open standards. 
Cummins Northwest Emergency Power Systems
Control Network Solutions Control Network Products
Curtis Door Systems Platform Door Systems with LonWorks Interface
EKE Electronics Ltd. Jari Jarvinen Yes Gateway between IEEE 1473-L and IEEE-1473-T under development
Echelon Corporation Glenn Dahl Yes Training, development tools, transceivers, control modules, Device Managers
Faiveley S.A. Paul Monard  Yes Platform and Train Door Systems
GeoFocus  Jim McGinnis Master Mobile Information Terminal  
Satellite Mobile Information Terminal 
GE Transportation Systems
Global Signaling
  Train control communications sub-systems interoperable with Safetran Systems

Advanced Automatic Train Control System

Group Alpha LonWorks based subsystems for rail transit vehicles. Braking subsytems
Knightronix, Inc Arnie Knight Yes ECP Braking Control Systems
Knorr Brake Corp David Drury Yes EP-60 Baking systems
Luminator (Mark IV)  Scott Yarberry Passenger Information sign systems
Microsym Greg Neff Yes Packet Tunnel Engine  (tunneling routers)
Nippon Signal Train Line Interface Systems for Advanced Train Control (See GE above)
Quester Tangent David Gregson Vehicle Monitoring System
Logic Control Unit

Health Monitor Unit
Rail Transit Consultants Rick Lerew Vehicle Monitoring Systems
Rolls Royce Auxiliary Power Systems
Safetran Systems
Bill Petit Yes S3 Link™ - Direct Sequence Spread Spectrum Radio

® - Advanced Solid State Interlocking
Some systems are interoperable with GE

Grade Crossing Predictors
SA Viewcom Mikael Obelitz Yes Audio/visual passenger address and passenger information systems
Sepsa Julia Gil Pizarro Yes
SmooCom Rob Grossenbacher IEEE-1473-L Routers
Technologies Lanka, Inc. Paul Cartier Train Network Communications
PowerPoint Presentation (1.2 MB)
Thermo-King HVAC systems
Telecite (Alstom) Jo-Li Wo Yes Passenger Information Signs
Trans-Lite Bill Maley Jr.
Passenger Information Signs
Union Switch & Signal (Ansaldo Signal) Denny Pascoe MicroCab® 
Vapor Yes Intelligent Door System 
Train passenger door systems
Wabtec Richard Mazur


ECP Braking systems
Door Systems


8. Where Can I find Consultants & Integrators?

The following firms have experience with LonWorks-based systems in the areas of Specifications, Design and Design Review. The services of a firm with experience in Specifications development are likely to be engaged by an end-user, such as a rail transit operator. Services of a firm with design experience are likely to be engaged by a rail car builder or a subsystem developer or possibly a rail transit operator. The services of a firm with design review experience are likely to be engaged by a rail transit operator or a rail car builder. 

Please feel free to contact  these firms directly or also TSD to help us assess your needs. (Please tell these firms you learned about them via the TSD web site.)

Firm Name



 Recommended Areas of Expertise

Oakland, CA USA
Ray Louis Specifications
Design and Systems Integration
Design Reviews
Booz | Allen | Hamilton
McLean, VA USA
Al Scala Specifications
Echelon Corporation
San Jose, CA USA
Glenn Dahl Yes Specifications
Design and Systems Integration
Design Reviews 
Knightronix, Inc Arnie Knight Yes Specifications
Design and Systems Integration
Design Reviews
LTK Engineering Services
Ambler, PA USA
Jim Lyke Yes Specifications
Rail Transit Consultants
Philadelphia, PA USA
Dallas Spedaro Specifications
Design and Systems Integration
Design Reviews
Microsym Corporation
Toronto, Canada
Greg Neff Yes Design
Systems Integration
SA ViewCom
Hillerød, Denmark
Mikael Obelitz Yes Design
Systems Integration
Philadelphia, PA USA
John Ewing Yes Specifications 
Transportation Systems Design
Oakland, CA USA
Tom Sullivan Yes Specifications
Design Reviews


9. Where can I obtain Courses & Training?

Training in LonWorks technology is available from multiple sources worldwide including Echelon, the technology developers. Click here for course dates and locations. The George Washington University's Center for Professional Development also offers CWEG 118 Advanced Communications Based Train Control  that includes design techniques for building open interoperable train control systems based upon IEEE-1473-L.
For more information please contact Tom Sullivan.

10. Where can I get Fast Answers to Technical Questions?

Glenn Dahl
USA & Europe
V:  +1 (516) 676-6622
F:  +1 (408) 790-3494

For over 10 years, Echelon's Glenn Dahl has been providing technical assistance to transit operators, railroads, rail car builders, system integrators and consultants worldwide. As a result Glenn is world's foremost authority in applying LonWorks to transportation systems. Echelon, a leading LonMark Interoperability Association member works with other LonMark members to help ensure systems based upon LonWorks are fully open and interoperable. The following Echelon contacts may also be able to help if Glenn Dahl is not immediately available: 
Laura Klein CA USA
Voice: +1 (408) 938-5256
Fax:    +1 (408) 790-3387

Lawrence Chan
Voice: +852 90 272 896

Transportation Systems Design, Inc. (TSD.ORG)
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Last Updated:  02/27/05