For your convenience, you may click on any of the following term's to be taken to the definition for that term.

Basic Shapes

Basic shapes are things that the builders of the prototype would have used as raw materials. For example "I-Beams," scribed siding, embossed brick sheets, and scale lumber are considered basic shapes. Assemblies such as ladders, or detail castings such as door or window castings, (Including cast wall sections with windows doors or other features.) are not considered to be basic shap



A "car" is just about anything that runs on rails, and is not self propelled.

Contest awards

Contest Awards: each contest model at any level of NMRA Sponsored competition that recieves 87 1/2 points and has been evaluated using NMRA contest rules may be used to satisfy the Merit Award requirements for the following categories: Master Builder Motive Power, Master Builder Cars, Master Builder Structures, Master Builder Scenery, and Model Railroad Engineer - Civil.

Merit Awards

Merit Awards are special awards which are sponsored by the AP. They may be granted by either the official judges at National, Region, or Division model contests, or by two or more special evaluators appointed by the Regional or Divisional AP Manager to view and evaluate the models of the member requesting certification at an agreed upon location in their Region or Division.

Note: Merit Judging of models on layouts is valid only on the official AP Merit Award-Certificate Evaluation forms obtainable from the Region AP Manager and on the website.

Merit Awards shall be granted to models recieving a total point score of 70% of the total points ( 87 1/2 out of 125 points in other words.) according to the following schedule:

Category Factor Point Range
Master Builder Motive Power Construction 0-40
Master BuilderCars Detail 0-20
Master Builder Structures Conformity 0-25
  Finish & Lettering 0-25
  Scratchbuilt 0-15
Category Factor Point Range
Master Builder Scenery Terrain 0-35
  Structures 0-20
  Background 0-25
  Lighting 0-20
  Realism/Conformity 0-25
Category Factor Point Range
Master Builder Prototype Models Terrain 0-35
  Structures 0-35
  Background 0-15
  Lighting 0-5
  Realism/Conformity 0-35
Category Factor Point Range
Model Railroad Enginer Civil Construction 0-40
  Detail 0-20
  Conformity 0-30
  Finish & Lettering 0-10
  Scratchbuilt 0-25

Note on Civil Evaluations of Track:  There are three alternative criteria to achieve a Merit Award score:  A self-powered locomotive that successfully traverses all routes gives a Workmanship score of 40; if all track meets the applicable NMRA track standards (S-3) using the appropriate track gauge, the score for conformity is 30; and if the track is built with scratch built frogs and points, the scratch building score is 25.  If the three criteria are met, the score is 95, sufficient for a Merit Award.


Merit Judging

In many AP categories, you will see requirements that your work must have earned a score of at least 87-1/2 points in Merit Judging.

This can be done in one of two ways:

  • The first is through judging at an NMRA sponsored contest.
  • The other, and often overlooked, way is to arrange for evaluation at another time.

Motive Power

Motive power is any type of steam, diesel, or electric locomotive, traction unit, maintenance vehicle, or other type of self propelled vehicle that runs on rails. This includes everything from speeders to Big Boys. It does not include hand cars, or unpowered models of powered prototypes ( Dummy Locomotives ).

Passenger Car

Passenger Cars include anything that would normally be found in a regular scheduled passenger train including baggage cars, RPO cars, express reefers, business cars, or other passenger carrying cars like Drover's cabooses.


Operable as related to motive power or cars means that they must be able to roll on the track, negotiate a curve, pull, be pulled, etc. In the specific case of motive power, the model must be capable of self-propulsion. Trains must be able to negotiate track work without derailing.

Scratch Built

To be considered scratchbuilt, a model must have been constructed by the applicant without the use of any commercial parts except

  1. Motor
  2. Gears
  3. Drivers and wheels
  4. Couplers
  5. Light bulbs
  6. Trucks
  7. Bell
  8. Marker and classification lights
  9. Valve gear (not driving or side rods)
  10. Car brake fittings
  11. Basic wood, metal and plastic shapes

A model is considered "scratchbuilt" if at least 90% by count of the model's pieces/parts (other than those specifically exempted in the list above) are fabricated by the modeler. This is an objective quantitative assessment based on the number of pieces with no weight given to complexity. This is a separate determination from the scratch building score.

The term "scratchbuilt" carries the implication that the builder alone has accomplished all of the necessary layout and fabrication which establish the final dimensions, appearance, and operating qualities of the scale model.  This definition does not prevent the use of any tools or jigs as long as the builder alone has done the work necessary for the tool to make the part.  This would include drawings or computer files to control CNC, automatic lathes, laser cutting machines, 3-D printers, and other tools.  If a third party changes the builder's inputs, then the parts are not considered to be scratch built.



Statement of Qualification: a form available from your Regional AP Manager or the NMRA website, which is necessary for completion of any AP category.

Super Detailed

To be considered "Super Detailed" it is necessary that a model have considerably more detail of excellent quality than is usually expected. The quality of the detail is of more importance than is the quantity. The applicant may qualify with Superior Craftsman Kits providing that, in the opinion of the Regional AP Manager, real individual craftsmanship is demonstrated.

Models falling within the following categories may also be considered as "Super Detailed".

  1. Cross-kit models
  2. Modified kit models
  3. Parts built models
  4. Extensively altered assembled models: e.g., to a different prototype. In addition such models are to have more detail.


For those categories which require that someone act as a witness or a judge to the accomplishments of the member requiring certification, a qualified witness shall be:

  1. Past or present National or Region Officers can witness the NMRA Service Certificates - Volunteer and Official if they have first hand knowledge of the service.
  2. Past or present National Contest, Regional Contest or Achievement Program Manager or AP committee members doing evaluations in their own Regions.
  3. Past or present National, Region or Division AP Manager or members holding the certificate can be witnesses within their own geographies (Region or Division);
  4. NMRA members appointed by the Region or Division AP Manager as committee members, evaluators or witnesses within their Region or Divison (not outside their Region or Division).
  5. For the Chief Dispatcher certificate, an exception is that the layout owner or dispatcher during an operating session can verify the tasks and time a member spent operating.  Though perferable, these do not have to be NMRA members if the operating sessions can be verified if needed.

All witnesses must be current NMRA members and put their NMRA number on the witness form.

Further Information

Contact National Achievement Program General Manager, Frank Koch achiev [at], or your Region or Division Achievement Program Manager for more information.