The Light at the End of the
Tunnel
Article & photo by Tom Troughton, MMR
How many times have you entered a fellow model
railroader's train room to be awe struck at the
magnificent layout before your eyes. There're several
hundred feet of meticulously constructed hand laid
track, on tie plates even, track side signals changing
colors when trains roll past and sound effects coming
from every nook and cranny.
The model builder tells you that the layout
represents the "ABC" railroad as it existed on
July 9, 1947, and contains several scratch-built models
of engines, cars and structures. They look great also,
running through rolling countryside, deep mountain
canyons and across spindly wooden trestles.
Then you happen to spy a train about to roll into
view from one of the hand-carved tunnel portals dotting
the layout. The headlight comes into view and the train
exits, moving on to points west. However, your eye
catches a glimpse of something else in the tunnel.
First you see a couple of red and black wires. Then
there’s the familiar green colored form of a Tortoise
switch machine. Further into the tunnel you see a couple
of wooden braces, probably made from an old pallet
picked up at a warehouse loading dock. Finally there are
the risers supporting the hand-laid with code 40
weathered rail branch line. The impression of a super
model railroad layout just went down the drain.
The real world scene inside the tunnel is one thing I
didn’t want to be seen on my Cimarron and Tall Timber
RR. I realized that when I switched to Sn3 scale a
couple of years ago. The new scale allowed me to operate
engines equipped with lighting and sound systems and I
wanted to create realistic situations on my new layout.
I wanted to see the headlight beam bouncing off the side
walls and to hear the sound of the chugging engine
diminish when it entered a tunnel and increase as it
exited.
Lining model railroad tunnels is a relatively easy
thing to accomplish. You can make your own liners with a
plastic mold made by Woodland Scenics. They offer a
curved top tunnel liner for single or double HO track. I
purchased one at a railroad meet and poured my first
casting the next day. Two castings are needed to make a
complete lining. Taping the two together with duct tape,
I placed the arch over my track and measured the
clearances with the Sn3 NMRA Clearance Gauge. The gauge
just fit inside the opening, only touching a bit at the
top center. I merely removed some of the plaster with a
Stanley Surform tool to clear my Sn3 equipment.
I made several castings from dental plaster, my main
scenery material. When I’m casting liners, I don’t
get much layout work accomplished because I’m always
going back to my workshop, checking the castings and
pouring another as soon as one is finished. When a
casting was removed from the mold, I used the Surform
tool to smooth the edges, remove some from top center
and knock off any flash. They were taken outside and
placed on an old window screen supported across a couple
of bricks. The screen allows air to circulate completely
around the castings so they dry quicker.
Before installing them on the layout, I sprayed the
tunnel sides with Krylon gray paint, then did a hit and
miss spraying with black, to suggest smoke and soot from
the engine exhaust. This proved to be a mistake as it
made the interior of the tunnels too dark. Under
realistic conditions, they would probably be covered
with soot, but the dark color reduced the effect I was
hoping for with the layout. To correct the problem, I
will dry brush some white paint on the linings to
lighten them up a bit.
Installing the Woodland Scenics linings on the layout
is fairly easy and since the tunnels didn't need to be
lined beyond what could be seen through the portal, I
didn't have to line the full length.
I used Homosote for a roadbed for all my track. It
was cut 2 3/4" wide. There's about a half inch of
subroadbed material extending out beyond the roadbed for
the linings to rest upon. I held them in place, one at a
time, drilled pilot holes through the plaster, and
inserted 3 penny finishing nails through the holes into
the Homosote. When the track curves, I’ve used the
Surform tool to taper the top portion of the liner side
to curve with the track. I used duct tape to hold the
tops of the castings together. If I ever have to work on
the track in a section that's covered with the tunnel
castings, all I need to do is untape the pieces, pry out
the nails and remove the castings.
I wanted to make my own liners for a few situations
where the double track feature of the Woodland Scenics
mold wouldn't work for me, since it was designed for HO
scale. I had a neat rubber mold of a fairly straight
piece of rock. I made a casting of it and carved out a
4" x 5 1/2" piece. I smoothed the surface
irregularities from the castings to make it flatter,
since the men boring the tunnels in real life would have
knocked or blasted them off anyway. When I was happy
with the casting, I made an RTV mold of it.
These castings are rectangular in shape and don’t
offer any ceiling effect. I used them differently than
the curved topped liners. These flat liners are
supported on untempered Masonite that I ripped to width
on my shop saw and fastened to the layout with sheet
rock screws. The liners are secured to the Masonite with
Liquid Nails.
I discovered that I had to add small strips of the
Masonite to widen my subroadbed, especially on the
curves, because the cab roof overhang from the K-36 and
K- 37 engines I run hit the lining.
Since the tunnels will have portals, I didn’t try
to hide the tops of them with rock faced castings. I
merely put a piece of heavy cardboard across the tops of
the castings. The tunnels are as dark as a tomb when
viewed through the portal.
It took me about a month of pouring, coloring and
gluing to install liners to my tunnels on the scenic
portion of the layout. I’ve got about another fifteen
feet of liners to pour and install, but I'm not in too
big of a rush to complete them yet.
The liners are a nice visual effect to the layout.
They also help the sound because when an engine enters
one of the lined bores, the sound drops realistically,
as in real life. It’s also a nice effect to look
through one of the portals and see the light from the
engine bouncing off the side walls as it approaches and
blasts into the open.
Liners are cheap and easy to make and add that bit or
realism missing from model railroad layouts across the
land. Give them a try. I think you’ll like them.
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