KB945: What does the NMRA Conformance Seal mean?

This article was last updated on Sept. 4, 2011, 4:14 p.m. | Print Article | Leave Feedback

It means just what it says. "This Product Conforms To All Applicable NMRA Standards."

An NMRA Conformance Seal is NOT an endorsement by the NMRA.

It is NOT a guarantee by the NMRA or by the manufacturer.

It is merely a statement that a particular product conforms to a particular test set up and administered by NMRA volunteers to assess whether, in their opinion, the product conforms to a particular NMRA Standard. Interpretations of this statement vary widely depending on whom you ask for clarification.

The Real Issue is Interoperability

Interoperability means that you don’t have to worry about a single source system. It means competition in the marketplace so that you have more choices and better prices.

Many manufacturers in the DCC industry have produced DCC interoperable systems for several years without the NMRA's conformance process. These manufacturers will continue to produce compatible products and will continue to work hard to ensure backward compatibility with existing DCC equipment when new products are brought to market. As manufacturers, we realize the importance of interoperability to you, our customers. But, in reality, there is no absolute guarantee of DCC interoperability. The what the NMRA calls their DCC "Standard and Recommended Practices" are loosely drawn in some areas and narrowly drawn in others. The "standards and RP’s" are open to interpretation and sometimes different engineers do come up with different interpretations of the same "standards" document.

You may have heard about (or seen on the net or on the DCC SIG) discussions and lists of DCC compatibility problems posted by various (sometimes partisan) individuals. Some of the issues listed are "legacy" issues with DCC equipment that was produced before the "standards and RP's" had progressed to their current state.

Other issues have to do with products produced based on variations in interpretation of the "standard & RP's". Because DCC has evolved over many years and is continuing to evolve today, compatibility problems can be expected to arise from time to time.

Unfortunately, we have seen several products with conformance seals that have interoperability problems, too! The good news for consumers is that most of the time DCC equipment is interoperable because the DCC manufacturers take the extra time to be sure that it is. And even when there is an interoperability problem, there is usually a workaround offered by the manufacturers to get you up and running again. All of the major DCC manufacturers really do offer excellent customer service and support.

Even though the NMRA issues Conformance Seals you will continue to see many products that are DCC "compatible" but not necessarily "conforming." Even though the NMRA may have "tested" certain products, and issued conformance warrants for those product samples tested, there is little or no control over the products that actually wind up on retailer's shelves.

The bottom line on NMRA compatibility/conformance is that it we really count on the DCC manufacturers to maintain DCC interoperability. Chances are that you will never experience any interoperability problem with your DCC equipment regardless of whether it is NMRA DCC compatible or conforming and if you do, the manufacturers, not the NMRA, are the ones who will take care of any problems you might encounter.

In 1996 Digitrax received a conformance seal for the DB100 Challenger Command Station (Challenger was retired after 5 years of production in July 1998). Based on our experience in obtaining the Challenger Conformance warrant, we chose not to submit any additional Digitrax products for testing at that time.

Between 1996 and 1998 Digitrax worked privately with the highest levels of NMRA leadership by making them aware of some very serious concerns that we had regarding 1) the actual testing being performed, 2) the lack of documentation of that testing, 3) the conflict of interest of individuals involved in the program, 4) the legalities involved in the whole process and 5) the need for guaranteed confidentiality during testing of new products. 

In 1998 we decided to submit the DB150 command station for conformance testing because we felt that progress had been made on some of our concerns.

In October 1998, the NMRA awarded a conformance seal to the DB150 command station (this is the command station used by the Genesis II, Empire Builder II, Super Empire Builder and Empire Builder Xtra Starter Sets). 

The experience with the DB150 showed us that our concerns had not been addressed fully enough to justify additional submissions for NMRA Conformance testing.

Digitrax has no plans to submit future products for conformance testing.

Digitrax will continue to concentrate on building products that interoperate with other DCC compatible systems.

We will continue to cooperate with the NMRA and its volunteers in their efforts to establish standards and RP’s that make sense for the hobby and are not overly restrictive or unfair to any manufacturer.

We will not support any change to NMRA Standards or RPs that will adversely affect products made by any manufacturer that is currently in the field because we feel that this would also adversely affect model railroaders who own those products.

Digitrax will continue to pursue our goal of a Complete Train Control System that operates with DCC but is not limited only to that technology.  Digitrax customers will continue to have the best train control we can offer. The Digitrax System is interoperable with the NMRA DCC "Standards and Recommended Practices" but is not limited to them in the features that are offered by Digitrax. The NMRA's DCC "Standards and Recommended Practices" are just one small subset of Digitrax Complete Train Control and Digitrax LocoNet's much broader system capabilities.

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