General HO Standards

Track Standards

     A. Scale

     B. Prototype Portions Modeled

     C. Functional Concept

     D. Structures

     E. Equipment on Layout

     F. Operation



A. Scale

     1. The primary scale of the Carriso Gorge Exhibit shall be 3.5 mm equals 1 foot, known as HO scale.

B. Prototype Portions Modeled

     1. The San Diego Model Railroad Association's HO exhibit is based on the San Diego and Arizona Eastern Railway from San Diego Union Station Eastward to El Centro, California. In addition, the branch line from San Diego to Foster is also modeled. The SD&AE Coronado branch will not be modeled.

     2. A portion of the AT&SF Railway from National City, California Northward to Rose Canyon and beyond is also modeled. This portion includes the AT&SF freight yard, the freight spurs and common trackage at Union Station, and the hidden North Loop.

     3. The 3 ft narrow gauge leaving Plaster City is based on the prototype U.S. Gypsum Corporation Narrow Gauge Railway.

C. Functional Concept

     1. The layout is constructed as separate portions, each of which may be operated independently. These are:

     2. Conventional DC throttles are used on all portions of the layout. The branch line and narrow gauge use Innovator commercial throttles with automatic short circuit crowbar protection, while the remainder of the railroad uses member-constructed heavy-duty throttles which are protected by external circuit breakers for short circuit protection.

     3. A DCC system is also installed on the HO layout. A Command Station manufactured by NCE controls the entire layout. 10 amp boosters are installed at every panel, and Tony's quad power shields provided power via block toggles to the track. Blocks can be shut off for short circuit isolation, and selection of toggles further isolates groups of tracks. Conventional DC throttles are isolated via a member built relay panel during DCC operations. At the current time, wireless cabs are not used on the HO layout due to interference with adjacent layouts in the Museum.

     4. A separate NCE Command Station is used for programming decoders on a dedicated programming track. Use of a separate Command Station prevents inadvertant interaction with other locomotives on the layout. The programming Command Station is also available as a spare should the main Command Station fail during an operating session.

D. Structures

     1. The goal of the Association is to construct a museum-quality exhibit. Integral to this is the requirement for accurate models of existing or historical prototypical structures of San Diego and Imperial Counties. Structures include railroad related buildings, bridges and trestles, recognizable commercial buildings, and free-lance buildings which capture the flavor of an area but where existing buildings may not be used due to space limitations.

     2. Where possible, historical structures will be constructed from original plans. If such plans are not readily available, photographs may be used. In some cases, a visit to the structure for measurements may be possible. Free-lance structures may be constructed by combining photographs of two or more existing buildings.

     3. Commercial kits may be used for generic structures such as tilt-up warehouses, residential houses, or may be used as parts for near-prototypical structures.

E. Equipment on Layout

     1. All equipment running on and scenery attached to the layout shall be HO scale. The large vista areas do not require the use of forced perspective. Painted backdrops shall not cause equipment to appear out of scale.

     2. British OO scale equipment (4.0 mm equals 1 foot) may be operated on the club layout provided it meets clearance requirements and has been granted a variance by the member-in-charge. OO equipment is by definition non-standard, and is exempt from NMRA Standards and Recommended Practices, although non-RP-25 wheel flanges are likely to cause problems. Foreign prototype equipment may be equipped with other than Kadee-compatible knuckle couplers (link and pin for example), but operation must be reliable.

     3. Non-standard is defined as cars, locomotives and streetcars that do not meet club Standards. Non-standard equipment may only be operated with a variance granted from the member-in-charge. A variance is valid only on the day issued. Permanent variances may be issued by the General Manager, or the chief carknocker. Owners of equipment failing to meet NMRA specifications must remove equipment from the layout in the event operational problems are encountered. A variance is voided when equipment is removed and may not be returned to the layout without re-inspection.

     4. When equipment is damaged, the member causing the damage is to notify the owner and the member-in-charge. The owner may choose either repairs or replacement and the member causing the damage is to honor the request. When a guest damages equipment, the host member is responsible. Damage to scenery is to be reported to the member-in-charge. After damage to any portion of the layout, a bad order slip must also be completed and dropped in the Association layout mailbox. Damage which affects normal operation should also be listed on the whiteboard to alert future crews.

F. Operation

     1. The member-in-charge is the final authority for operations. The following variants are recognized operations styles:

     Note: Panel operation does not work well with DCC.

     Branch line operations may follow any of the above variants. In addition, trolley operation has priority on the branch line. Other equipment must interleave with trolley operations and use care to not overrun gaps into trolley-equipped blocks.

     2. The Vice President/General Manager when present may overrule the member-in-charge in all matters related to operations.

     3. Members of visiting clubs must abide by the same rules, regulations, and standards as members of the San Diego Model Railroad Association. A visiting club must designate one of their members present as their representative in case damage to the layout or equipment occurs.


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