Wednesday, May 25, 2011

Mountain Tunnels - Part I

Before I could start the tunnel structure, which would be the base for the future mountain, I had to finish the track. First was paint. I experimented for a few days to find a method that covered quickly, and looked effective. Since my layout is right beside my furnace and hot water tank, and there is no ventilation, spray paint and enamels were out of the question. That left me with hand brushing with water-based acrylics.

Painted railroad tracks

To paint the track, I used Burnt Umber acrylic, mixed with a bit of grey and thinned it with 25% water and 25% isopropyl alcohol (70%). This mixture covered well, and dried quite uniformly on the ties and in the webs of the rails. I had to use extreme caution when painting the turnouts, making sure I moved them frequently while the paint dried so they didn’t get stuck in place. Once the paint was dry, I cleaned any paint off the top of the rails using a fine grit sanding block.

Painted railroad turnoutsPainted railroad tracks

With the track painted, the last thing I needed to do was ballast the track. Unlike painting the track, I only ballasted the track that would be in the tunnels. This would allow me to finish the rest of the scenery on the layout and avoid having to work around the ballasted track.

Right tunnel entrances with portalsFuture mountain tunnel entrance positions

I used Woodland Scenics Medium Buff ballast. This, like most everything else, was my first time ballasting track, so doing it in the tunnel sections, where it would be a lot less noticeable, was a perfact place to start.

Left tunnel entrances with portals

I used a method that I found to be most popular in my online research. This method is to lay your ballast on the track and shoulders, then use a brush to level it between the ties and make it uniform. Then, using alcohol and an eye-dropper, gently wet the ballast. This reduces the water tension when adding the glue, and allows the glue to wick better through the ballast. Once the alcohol soaks in, apply a liberal amount of white glue, thinned 50% with water, and let this soak in as well. Be careful not to add too much glue at once, or your ballast with start to flow away. Once the glue completely dries, about 24 hours later, the ballast will be hard as concrete!

Tunnel entrance with track ballast

One thing I learned from this first ballast attempt is to not use too much ballast. You can always add more, but using too much makes things messy, and it’s almost impossible to brush all of the granules off of the tops of the ties. Model Railroader Magazine has a really good article in their February 2011 magazine about ballasting track. They explain a 2-part application process of ballasting, where you first apply glue, then ballast, then re-apply ballast and glue again. This method looks really nice in the end. I just might try this when I complete the rest of my track.

Tunnel entrance with track ballast

With the track and tunnel portals complete, I can finally start building the large mountain which the 2 tunnels will run through. Before I can build the mountain, I need to build each tunnel structure, which the mountain scenery will sit on. Each tunnel, which will include the supports, the walls, and a common ceiling, and will act as the base for the mountain.

The first task is accessing de-railed trains inside the mountain. The double wide tunnel is wide and short enough that I can access the inside of the tunnel from either side. The smaller, single tunnel which goes under the double tunnel, is the opposite situation. To solve this, I cut an opening in the benchwork right beside the track. This will allow me at least some room to retrieve a train if it becomes stuck in this tunnel.

Track access hole

Tunnels are dark, so to keep things as dark as possible, everything inside the portals was painted black, with no exceptions. Since there were sections of the tunnel that didn’t have a complete wall, it was important that everything was blacked out, so nothing could be seen inside the tunnels. I used cheap black acrylic paint from the dollar store, which worked great for this purpose.

Mountain tunnel interior area painted blackMountain tunnel interior area painted black

I then used Styrofoam to start building the walls. I used a combination of white glue and toothpicks to hold the foam together and keep it in place while the glue dried. Once dry, each wall section was painted black. I did visual checks on each end with the portals in place, to ensure that no wood or white Styrofoam was visible from any angle, and if there was, I quickly covered it with black paint.

Foam walls and supports for tunnel structureFoam walls and supports for tunnel structure

Due to spacing limitations, I had to combine the small and large portal on the tunnel entrances on the right hand side of the mountain, as seen below. I cut off 1 inch at the left base of the large portal, and glued it to the top of the right side of the small portal. This now allows both portals to exist where they were both intended to be.

Construction of right tunnel entrancesConstruction of right tunnel entrances

The entrance to each portal is the most visible, so it was important that there were complete side walls on both sides of each portal, extending far enough into the tunnel so you could not see that it ended. As seen in the top portal, right side of the mountain, I used 1/16” wood craft board as a divider from the lower tunnel portal. This was to prevent light from either of the portal entrances, showing through to either the top or lower tunnels. I had to use the thin 1/16” wood craft board as the foam I had was too thick to use without interfering with the lower tunnel.

Mountain tunnel interior foam structure nearing completionMountain tunnel walls with portals in position

Once I ensured the tunnel portals fit correctly, and were temporarily in place, I did a final visual inspection to make sure everything was pitch black inside. I then used a large template to cut a solid one-piece foam roof for the entire tunnel structure. I attached foam supports on the back-board, secured with screws and glue, to support the back and left edge of the roof. I painted the roof and foam supports black, and glued it into place.

Tunnel walls painted with Mar’s Black acrylic paintCompleted foam tunnel structure

Any gaps were filled in with carefully cut pieces of foam, and upon my final inspection, there was not even a sliver of light visible inside the tunnels. Now I have a solid tunnel structure which my mountain can be built on top of, without any possibility of affecting the tunnels themselves.

Completed foam tunnel structure

Monday, May 23, 2011

Tunnel Portals from Scratch

To be a bit thriftier, I decided to build my own tunnel portals of the 2 mountain tunnels. I built them out of styrene plastic and to my own custom size and specification so they fit my track and tunnels perfectly. I started out by measuring the sizes that they needed to be, then made a scale drawing on paper to show how I wanted them to look. I then traced templates which I transferred to foam board, and cut mock-ups of each tunnel portal. I used these foam mock-ups to ensure each portal fit the track correctly.

Tunnel portal templatesFoam tunnel portal mock-ups

Once I verified how the portals looked with the foam mock-ups, I used the same traced templates to cut the main portal shape out of styrene. To give the portals their 3-D shape, I used a scrap piece of square wood doweling to ensure each side was glued at a perfect angle.

Wood bracing for portal constructionWood bracing for portal construction


Styrene tunnel portals under constructionFace of half completed tunnel portals

I then used a thicker piece of styrene for the top of each portal, which each had a slight overhang. You can notice one of the large portals is flush on its right hand side. This is because it will but directly up to the backdrop.

Tunnel portals with topsCompleted single and dual tunnel portals

I then added the final details, which included an extending arch over the portal entrance, which wrapped around the portal itself. Wide footings were added to the base of each portal, and a curved inner arch for the roof was also put in. The last thing will be to paint them, however I’m not sure what colour they will be until I get further into my scenery.

Completed single and dual tunnel portalsCompleted single and dual tunnel portals