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Construction, Lighting, and tracklaying.

Benchwork and Scenery.

Two factors led to the benchwork for the KMR being much lighter than is conventional. First, from its design, the benchwork would never need to support more than it's own weight. Second, the space occupied by the structure between the upper and lower decks was to be miminised.

Thus, the upper level layout joists were from clear 1"x2" lumber, cantilevered from the 2"x4" stud wall (typical stud spacing of 16") that formed the back surface of the layout.  The joint where each joist was bolted to the stud was reinforced by a metal bracket, screwed to the joist and stud. This is shown at right. The structure was further strengthened by the fascia, (from 1/8" hardboard) which was screwed to the ends of the joists, the strengthening being more significant when the fascia was sharply curved.

The joists for the lower level benchwork, where space considerations were not critical, were from 1"x4" or 2"x4" lumber, again bolted to
Benchwork construction at 90BD
90BD at a later stage of construction.



and cantilevered from the stud wall. The lower level fascia was again screwed to the joist ends.

Lumber 1"x2" in size was also used to rough in the structure of the lighting valence and the "ceiling" for the upper level, both clad with 1/8" hardboard. The ceiling was necessary since the viewing angle into the upper level scene is upward for many visitors. The layout backdrop was also from 1/8" hardboard, glued and screwed to the studs.

The subroadbed was from 1/2" plywood, screwed to the joists. The roadbed was from 1/2" insulation board ("Donnaconna"), glued to the subroadbed.

Scenery was by plaster-gauze applied over form-work of screwed up balls of newspaper. Where necessary, additional layers of texture-paint were applied, and the whole painted with artists' acrylic paints. Final texturing was by Woodland Scenics ground foam.

At left is seen the same area as above, but later in construction, before installation of the lower level trackwork.

The helix shown in the trackplan was installed inside and supported by the back of the stud wall, which supported the backdrop in the region of Soda and the Homestake Gulch trestle on the upper level, and Clanwilliam on the lower level.

To keep the grade on the helix track at an acceptable 2%, it was necessary to make the roadbed and its support as thin as possible.  The roadbed was two layers of 1/4" plywood glued together, supported by 3" hardware-store metal brackets screwed to the studs. The positions of the brackets was carefully adjusted to ensure a constant grade throughout the four turns of the helix. This view also shows the helix occupancy detection system.

The Okanagan staging loop on the lower level (located below the lowest turn of the helix) is free from the above benchwork thickness constraints. It is therefore supported by 1"x2" joists cantilevered from the studs.

Helix construction

Trackwork.

Dual gauge switches at Sicamous. The track switches ("turnouts") were all built to suit their location, using nickel-silver rail soldered to printed-circuit-board (PCB) ties using techniques learned from Ed. Stimson, many years ago. Rail sizes were code 55 for the narrow-gauge main line, and code 40 for narrow-gauge secondary trackage. For standard-gauge, the main-line was from code 70 rail, with secondary trackage and all dual-gauge track from code 55 rail.

Track between switches was from Micro-Engineering Flextrack, with the same rail sizes as above. The light rail sizes have proved quite practical during some years of operation. Standard wheel flanges are found to have adequate clearance from the ties, and the track has an appearance much closer to that of the prototype.

Switches were designed, and the PCB ties gapped, to provide for frogs to be powered positively through an under-the-benchwork slide switch , seen at right, actuated by the switch throw-rod. Switch rails are also positively powered, at the same polarity as the adjacent stock rails, thus eliminating short circuits by passing wheels.

Switches are also fitted with lit and working switchstands, by techniques which were described in the Gazette for Sept/Oct 1996.
The photo at right shows the crank mechanism which turns the switch stand, also actuated by the switch throw-rod.

On the outside of the fascia, each switch throw rod is terminated by a glued-on wooden ball. Following the example of Bill Darnaby, the hemispheres of the ball closest to and furthest from the fascia are painted with colours matching those of the corresponding switch stand target. Some of the balls are to be seen in photos elsewhere in this website.
Slide switches to change frog polarity.

Lighting.

Upper level lighting. It was decided at an early stage to use fluorescent lighting for the layout, for reasons of economy and to avoid excessive heat load. When the upper level was built, ordinary cool white fluoresecent tubes were used, in 2-, 3- and 4-foot lengths to match the curvature of the lighting valence, as seen at left. (For night-time lighting, we use incandescent blue Christmas tree lights, and the structures are lit with microbulbs from Cir-Kits.)

Almost all the photos in this website were taken with the fluorescent illumination. It is said that the UV component of the light from these tubes causes paint colours to fade, and styrene (used to build structures) to become brittle. We have not noticed such effects during the many years since the installation, perhaps since we finish models to look rather delapidated and dusty in the first place.

By the time the lower level of the layout was built, compact fluoresent lights had become available in cool-white and a range of wattages. After an experimental installation, it was decided to adopt these lights throughout the lower level.

These lights have several advantages. They mount in ordinary lamp sockets, and the intensity of illumination can be varied by changing between lamps of different wattage. A disadvantage is that the light source is more concentrated, so evenness of illumination is more difficult to achieve. However, unless the lamps are within a few inches of eg. the backdrop, this effect can be offset by a closer spacing of the lamps.

It has been found that a useful contribution to illumination of the lower level comes from the lighting for the upper level. This is particularly true where the lower level extends out much further than the upper level, as at Sicamous. To be sure, objects near the front of the layout are somewhat back-lighted, but the illumination is nonetheless a considerable aid in uncoupling and similar operations.
Lower level lighting.