The Model:  Construction Techniques

Benchwork

Several basic styles of benchwork have been used in the construction of the railroad.  Against the walls and at the center of the peninsula are hangers attached to the floor joists above and extending to below the bottom level.  These hangers provide legless support in areas where the layout is narrow, and allow cantilevered support of upper levels.   The hangers are 3/4 inch plywood cut to 3-1/2 inches wide and fastened to the joists with four drywall screws each.   Plastic sheeting attached to the bottom of the joists helps keep dust down until a dropped ceiling can be installed.  Where ducts or other obstructions prevent neat attachment, 3/4" plywood brackets have been used to attached to the joists:


The lower levels are typically basic box construction using both plywood sheet and open-frame-with-risers subroadbed support techniques. These boxes are usually supported on the wall or back side of the layout by attachment to the joist hangers.  Where the width requires, either legs or diagonal braces are used to support the front of the layout.



The upper levels are supported on brackets mounted to the joist hangers.  These brackets are either 3" or 4" deep at the back and taper to 1" deep at the front.  Their length depends on the layout depth at that point, which is usually determined by the track configuration or aisle width requirements.  Subroadbed will be 1" extruded foam attached to the brackets.  Where necessary, 1" wide strips of 1/4" hardboard will be used as longitudinal supports along the front of the benchwork.  They will be attached to the front of the brackets and will serve double duty as the supporting surface for the upper level's fascia.


Backdrops

The backdrop is primarily 3/8" gypsum board, which can be bent to a surprising degree of curvature to cover misplaced lally columns, cinderblock buttresses in the outer walls, and other architectural challenges!  Where sharper curves are needed, like at the coved corners, 1/8" hardboard has been bent to fit.  Again, surprising curves have been possible with judicious use of water misted on the hardboard before and during bending.  The joints between gypsum board and hardboard are levelled using 1/2" plywood shims under the hardboard, and ordinary drywall mud and tape fill the gaps and cover screwholes.  Painting is still to come, but typical drywall painting techniques are planned:  primer followed by two coats of topcoat.  The sky color has not been selected yet.  The high ridges present in most of the modelled area lend themselves nicely to thin profile foam "hills" about 1" in front of the backdrop, so little painting of scenery on the backdrop should be needed.

Roadbed and Subroadbed

Roadbed construction is typical:  Homasote attached to the subroadbed with white glue.  Subroadbed will vary with the area of the layout. In the yards 1/2" plywood will be attached directly to the supporting box.  In the Poconos transition from lower deck to upper deck, 1/8" hardboard spline will be the subroadbed, and on the upper levels the base will be extruded foam with the homasote glued down with hot glue. Surprisingly, testing has shown the hot glue provides a quick, strong bond and does not melt the foam.


Spline Roadbed, as perfected by Lee Nicholas on the Utah Colorado Western

Upper level construction technique, except the roadbed will be Homasote.


Trackwork

Trackwork is a mixture of commercial and hand-built components.  In the staging yards Code 100 commercial turnouts and flex track have been used, except on the western throat of the West  End staging yard.  This portion of the layout was salvaged from a previous layout and much of the throat is handlaid Code 83, with #6 turnouts.  On the western end of the throat I needed a curved crossover so that, too is handlaid.  

Visible track will be Code 83 on the Main Line and Code 70 on the Bloomsburg Branch and on sidings and industries.  Turnouts will be mostly handlaid but to save time the remaining track will be flex track.

Switch Control

Control of the track switches will vary depending upon prototype area.  Where the railroad used remote switch control, Tortoise switch machines will operate the switch and will be controlled by the Dispatcher.  Where the switches were thrown locally, control will be either groundthrows or a mechanical linkage operated from a knob in the fascia.

Staging yard switches will be operated by Tortoise machines.  The machines are connected to the switch throwbars using a linkage extending through the roadbed and a bell-crank type connection to transfer the linear Tortoise motion to the throwbar linkage (see the photos below).



Linkage to the throwbar before painting the PC board throwbar. Simple brass rod inside brass tube, the tube extends through the roadbed/subroadbed and protrudes about 1/2" below the subroadbed.  The rod extends about 1" farther to allow room for attaching the bellcranks.
 The under-table linkage.  The bellcranks are made from aluminum bar stock using a simple jig.  This linkage will be used wherever remote operation is needed, whether manually operated using a knob, as in this picture, or with a Tortoise machine.
 Tortoise switch machine mounting.  Machine and terminal block are glued to the hardboard mounting plate.  The hardboard plate can be mounted either horizontally against the plywood surface, or vertically on a riser or similar support.  The throwrod attaches to the Tortoise throw arm and connects with the bell-crank assembly shown at left.

 

Scenery

Since we have built little scenery, the construction methods are still in development.  Upper level scenery will likely be extruded foam sculpted to the desired contours and then finished with plaster, paint, and ground foam (see the photo above).  

For the lower levels we anticipate using a method similar to that used by Kelly Newton on Lee Nicholas' Utah Colorado Western (go to http://www.ucwrr.com/UCW.htm and follow the "Construction" link) .  Kelly uses cheese cloth over plastic bags filled with crumpled paper to form the basic scenery contours and then coats the cheese cloth with several layers of a thin plaster mixture.  He then adds a texturizing mixture of dry plaster and real dirt with dry coloring (if needed).   When forming his landforms Kelly ignores the track structure and covers the tracks where appropriate.  then, when the plaster is dry, he cuts the dry plaster/cheese cloth away where it is above the track and builds cuts or fills using more cheese cloth and plaster.  This results in a very convincing scenery forms and goes quickly.   We'll let you know how it works for us!

That's all for now.  Feedback and comments are welcome!
Send your thoughts to jwmutter@yahoo.com Thanks!

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