European DCC (NEM) compared to US DCC (NMRA)

NEM standards are the standards for model railroads issued by the MOROP. NEM stands for Normen Europäischer Modellbahnen (German) or Normes Européennes de Modélisme (French), both of which translates to European standards for model railroads.

The NEM standards cover areas similar to the standards and recommended practices defined by the NMRA in North America, but the two standards are not universally interchangeable. In recent years, MOROP and NMRA have been working more closely together to establish common standards for developments such as Digital Command Control. European model railroad manufacturers generally follow the NEM standards, while North American manufacturers generally follow NMRA standards instead.

The NEM standards are defined and maintained by the Technical Commission of the MOROP in collaboration with model railroad manufacturers.

The NEM standards define the model railroad scales and guide manufacturers in creating compatible products and assist modelers in constructing model railroad layouts that operate reliably. The standards cover areas like suggested gradients, turn radius's, wheel profiles, coupling designs and Digital Command Control and are mostly scale specific. A fundamental principle in NEM standards are compromises in the exact scale reduction ratio in order to favor operational reliability of model railroad systems. An example for this are wheel flanges which tend to be proportionally wider in smaller scales to ensure a reliable operation.


DCC is an acronym, identifying the Digital Command Control Standard created by the National Model Railroad Association.

The NMRA decided that what was needed in the command control arena was a standard. So committees were created and discussions held, eventually resulting in a proposed standard for command control. The NMRA Working Group decided that Digital was the way to go, and built their standard around digital technology. Previous command control systems were built around analog technology, with some systems built around digital technologies.

Prior to the introduction of the NMRA DCC Standard, the market was fragmented into a number of completely incompatible command control systems. See DCC History for more background.

Before you start thinking that a bunch of old guys sat around a table smoking cigars, sipping Scotch and making decisions, that wasn’t the case. The NMRA is made up of people just like you and me. The working group members offered their time and knowledge to create this, and other standards, so that everyone from you to the manufacturer will benefit, and the hobby benefits as well from these efforts. Not only did they ask modelers what they wanted, but they also took input from manufacturers in the model railroading industry, from small companies to large.

By defining a command control standard, which the NMRA named Digital Command Control, you are assured that any DCC branded product should work with any other DCC branded product. Those products will have the DCC Logo seen at the top of the page. The football shown below may also be present, but at this time many manufacturers of Digital Command Control products do not submit their devices for conformance testing by the NMRA.

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