I have completed the basic layout for
the Wampo, Nieke and Sonkrai railway. Before I glue down the track,
the bridges have to be built. The first bridge is the simplest, a
two-span deck plate bridge on three concrete piers.

The
prototype The prototype is the Apalon Bridge, about 25
kilometres inside Burma, beyond Three Pagoda Pass, at the 335 kilometre mark
from the railhead in Thailand. John Stewart described it in his book
To the River Kwai Two Journeys 1943, 1979, when he visited the bridge
on his return journey. At the time it had been abandoned for 35
years, and at that time, appeared to be intact, but appeared to be
freshly painted a dirty shade of red, like coagulated blood. From
close up, it is revealed to be nothing but deep rust which Stewart
says contrasted sharply with the pervasive greenness of the
jungle. A
photograph shows thick jungle right up to the edge of the pylons on
either bank.

Alternate world This project is more of an alternative
world, the
term taken from speculative fiction than the pure model railroading freelance. 
In this alternative world, the railway was not
abandoned; instead it becomes a mainline route from China and
Southeast Asia, as well as traffic between Thailand and Burma as well
as the local runs. However, in the post-war world, there is a minimal
budget, and so far, in the period 1946-1947, the maintenance on the
hastily built railway is concentrated near the railheads and high
traffic areas in Thailand and Burma. The border region that I am
modeling is on the list but at the bottom. So the bridge can be
described as neglected, and I have weathered it, as it would have
been in either world in 1946 or 1947.

A note on construction
In the construction of the Burma Thailand Railway, the wooden
bridges, ties (sleepers) and telegraph poles were made from local
insect resistant tropical hardwoods, mainly teak. At least during the
period of the Second World War, creosote was not available and not
used. That means the traditional methods of staining or painting both
the wooden trestle and the ties do not apply on this railway. Teak
and other hardwoods were used, usually untreated, for many years
after the Second World War across Southeast Asia. Later various forms
of anti-insect treatments were used. Today it is more common to use
metal and/or concrete for bridges and poles.

The model The
original model is made from two Kato N Scale deck plate bridges with
Kato pylons. There is a close resemblance to the original Apalon
bridge

The pylons I came upon a method of creating
neglected or decaying concrete purely by accident. I was testing
Krylon All Purpose White Primer #41315 on some scrap styrene. The
result was a powdery cracked white, not all suitable a primer, but
perfect for crumbling or neglected concrete.

First I sprayed the three pylons with Krylon primer. Once it was dry,
I applied a wash of Polyscale Concrete, allowed it to dry and then
applied two more washes.

The level of the Kwai Noi varies from day to day and sometimes from
hour to hour. Flooding is frequent during the rainy season. So how to
create flood/mud stains on the pylons? So I tried an experiment, I
created a bath of artists acrylics (raw umber and raw sienna), and
mixed it so it actually had a consistency of mud. I left the three
pylons outside in the sun, which reduced the bath and left a stain,
then transferred the pylons to my work bench, where the remainder of
the paint bath evaporated over three days, leaving an authentic
looking stain.


After the mud stains were dry, I applied artists pastel chalks, first
some raw umber followed, in the tropical environment with a bright
Phthalo Green, an Olive Green and then a mixture of the two. The
final chalks were Black, Mouse Grey and a mixture of both. The final
step was a Krylon matte spray to fix the chalks and remove any sheen.

The track I have already run experiments with spare
Kato Unitrack and Atlas Snaptrack. Both have ties that are too dark
to match tropical hardwoods. As is widely recommended, I coated the
rails with oil before each painting step.

What worked best was Krylon Satin Almond spray #42327, which creates
a dull grey-brown finish. The second step was also an experiment. I
had successfully tested Home Hardware Teak wood stain on bass and
balsa wood prior to building the trestle bridges. (More on that in
future posts) 

So I brushed the ties with the teak wood stain”and that worked,
bringing out the details of the ties and adding a teak-brown tone to
the grey from the spray.

However, this technique works best on track
without a built-in roadbed, since the stain tends to bleed into
roadbed. (I am working on a couple of other techniques with the
Unitrack) I then painted individual ties with a variety of washes
from Polyscale D&RGW Building Brown, Depot Buff and Mud, adding a
smidgen of Box Car Red now and again. The guardrail and the sides of
the rails were painted with Polyscale Rust.
I
added a wash of rust on the central walkway. It was chalk pastels
that made all the difference. First was for rust, Caput Mortuum Red,
Indian Red, Permanent Red Deep and Raw Umber (and mixtures of those
shades). There were several different shades of Raw Umber in
Curry’s Artists Supplies in Toronto, so I used those to add a
general aged appearance. As with the pylons, I used my selection of
green to add some hint of the jungle, followed by greys and blacks.

The spans Kato calls the colour of the deck plate grey. But it was
actually a grey green that was perfect for my needs since it closely
resembled camouflage paints, likely the only paint available in the
region at the time anyway. I used a small sculpturer’s pick to
distress parts of the bridge, weakening some of the side rails and
poking some small holes, which could have come either from allied
strafing or just general wear and tear. Again I started with wash of
Polyscale Rust, followed by a mixture of Rust and Building Brown, but
largely left well enough alone.


The main step was a heavy application of pastel chalks, several of
mixtures of a rusty orange, followed again by greens and finally by
blacks.

Finishing All the elements were sprayed with Krylon
matte finish, to seal the chalks and to remove any remaining plastic
shine. I gave the Kato unijoiners a thin wash of concrete, and added
a black gantry support in the middle, that I may use for a telegraph
pole or just leave as is. 

Next step The next step is
the first trestle bridge.