General Design

Givens:
a. HO Scale layout of the Placerville Branch between Folsom and Camino, California as it appeared and operated in the 1930's.
b. small steam - the largest steam locomotive ever to appear on the Pville Branch were Pacifics 4-6-2 and that was rare.The consolidation type locomotive was standard SP power on the branch.
"Engines not allowed on branch: A-3s, A-6s, mikes and larger. But Pacifics except P-8s, 10s and 12s were allowed. Also T-40 number 2371 was not allowed. It looks like anything without a trailing truck was allowed plus most Pacific's." Engines types per a 1949 employees TT - thanks to Phil Smith for this information.  
c.11x29 room size

Druthers:
a. double deck design with constant elevation gain around the room - no helix.
b. code 70 ME flex track except in staging (code 83 Atlas)
c. 24" minimum radius .  Lower level nominal height 42" Upper level nominal height 62" Steps stools maybe required for the vertically challenged Operator. Since the lower level climbs to meet the upper level level, deck spacing gets smaller and smaller as the lower level climbs. At this room size I gladly gave up deck spacing to not have a helix.
d. some degree of prototype - not to the level of copy track for track - although that probably wouldn't be too difficult given the Placerville branch track main, spurs and sidings. All you need is a large enough room.  I am more interested in a fairly high degree of accuracy when it comes to industries served, then I am in accuracy of track duplication. And I really want to attempt to maintain historical accuracy in my modeling efforts. When visitors arrive I want them to know right away this is not modern times.

Level O Staging
Level 1 Folsom to El Dorado
Level 2 El Dorado to Camino

Interior Construction

Next I turned my attention to the interior. There were several challenges here, most of which were met, some which have yet to be addressed.  The exterior walls were insulated. The wall facing the west underside of my house got a treatment of furring strips 16"OC for drywall attachment. The ceiling was insulated with 1" foam and then OSB attached. I had 3 vents from the underside of the house facing the room, where I created channel to run cool air from underneath the house to the rr room. Although air conditioning is a must for people comfort, the vents will all get 4" vent  booster fans to push cool from under the house into the room. It gets very warm where I live and with just the 2 full banks of flourescents going I can easily raise the temperature several degrees. With the planned use of CFL bulbs under the layout and the 5 or 6 folks needed for operation, an air conditioner will be needed. I digress. With the help of my friend Phil Gulley we added coving in 2 of the 5 corners of the room and after taping and sanding I painted the basic sky blue color that I will use for backdrop sky. Photos below show some of the construction.
Lastly I should write something about the electrical. I have 50 amps going into the room with 6 outlets . I didn't have the need to drop outlets every 6 feet. I just made sure I had a dedicated circuit for just the railroad and another for the eventual placement of room air, heat and dehumidifier. So far its worked out. I have blown a breaker a couple of times usually while the little portable electrical heater is cranking away and I start up a shop saw, with someone else working the table saw. I just didn't and don't see a need for a whole lot of breakers and house wiring on a layout of this size. Time will tell.

raw interior with external 2x6s in place

facing north toward eventual opening

east wall insulation  progress

treatment to south facing concrete brick wall. Notice porch tensioning cable at top

foam insulation in ceiling

2x3 furring strips to interior concrete brick wall.

box around porch tensioning cable in place top of photo

OSB ceiling in place.  Working lights going up
Notice 1 of 3 ceiling vents

ceiling and lights in place

me and the drywall

looking south toward door opening. Thats Moose at my side

taping and sanding in progress.
Thanks to Phil Gulley

Everything in several coats of white primer

1 of 2 corner coves using ¼" masonite
Now painted sky blue

An empty but completed interior room underneath the back porch

Room Construction

I started designing and building the Placerville Branch in 2010. I had switched prototypes in 2008 when I moved into town after living on acreage in the Sierra Foothills. I had been building a large GN layout of the Cascade Division in a separate shop building on the property. After moving to our in town home in 08 and with the help of several friends I started the design and building of a steam era SP layout centered around the iconic Placerville Branch that ran from Brighton, Ca. to Placerville in the Sierra foothills. The layout originally was to be in one bay of a two car garage, but my house faces east/west and afternoon sun really heated up the garage space, making it unbearable to work in. I did start insulating to try and beat away the heat, but my wife suggested an alternative area under the back porch. I looked this over and after some measurements decided it would be the future home for my Placerville Branch layout. The space measures 11 x 27 ft, so it is long and narrow with a low 8 ft. ceiling. Below shows the initial exterior construction photo's.

2x6 studs are installed along the long side of the porch

then T11 siding

Trim

and paint

The entrance is to the the narrow side, with a door that mistakenly opens in. Soon I will reverse it as it needs to open out to make room for a track running across the door face connecting upper and lower levels.