Weathering the Apalon Bridge



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 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. Aphotograph 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.


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.

 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.


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.


Starting the Wampo, NIeke & Sonkrai (Version 1)


May to October- Railway salvage?
It was after I finished  A River Kwai Story The Sonkrai Tribunal, that I decided to build
a model railway based on my research, to model the real bridges on
the River Kwai.

But at that time there was trouble brewing.
Management at CBC had applied for conciliation and that had started
the clock ticking towards the lockout that began in August. Money was
tight, but my basement was full of material left by the one the
previous owners of my house, that could potentially be used for a
layout. A large pile of wood, probably structural wood, taken down
when the wall was taken down between the living and dining rooms.
There were also two doors in the basement, not the standard hollow
doors available at your local hardware store. There was a solid door,
same pattern as the rest of the doors in my house and a hollow
cupboard door. So that became my planned bench work. The plans were
put on hold as it became clear that there would be a lockout and I
was working on the first round of revisions of the manuscript. In
August, the model railway gods favoured me while  my income was
reduced by the lockout. I was able to get more salvage material from
construction sites on my block. The first was some old-fashioned wire
mesh, three different types, which I picked out of a pile of
construction waste. Then a couple of weeks later, another house on my
block was being renovated. The exterior walls were covered in lovely
blue extruded Styrofoam. And a colleague and lockout picket captain
owns the house next door, so I was occasionally a visitor and one day
I was there when the contractor’s crew was outside and I asked
and received all their scraps.

October to
November. Layout planning.
The lockout ended (see


Garret Tree
for my blog on the lockout) and once my pay cheque
resumed, I dropped by my local Home Depot and bought one large piece
of 4 x 8 one inch pink Styrofoam and a couple of pieces of two inch 2
x 8 foam. I knew the rough layout and I what was essential, the great
Sonkrai trestle bridge in the centre of the layout and the
spectacular Wampo viaduct on one side. As well, by watching the
forums and e-mail, I concluded that for viable freelance operation,
the railway needed an economic reason to operate, over and above the
long-standing idea that it should be a short cut from Southeast Asia
and China to India. When I visited the region in 1997 I saw the
devastation of clear cut logging, similar to the cut, clear and leave
the slash that so familiar to me when I was growing up in British
Columbia in the 1960s. The Imperial Japanese Army had created small
sawmills along the route of the railway to produce ties and material
for bridges, so my economic assumption is that there was a small
post-war logging and lumber industry that provided some support for
local trains. So that meant a branch line going to the sawmill. The
layout is designed as point to point as the original railway was. But
since the Burma Thailand Railway had what were called air raid
lines with little clearance from the jungle that were designed for
trains to hide during Allied air raids, the return loop of an oval is
partly the air raid spur.

Christmas holidays
I built the bench work during the Christmas holidays.

and February
Going slower than I thought it would, but
then by monitoring the forums, it seems it goes slowly with everyone.
I glue down the base extruded Styrofoam. Then I layout the basic
track plan, using Kato Unitrack for the lines. I planned to use Atlas
Snaptrack for the many bridges (there were 688 bridges on the Burma
Thailand Railway). My plans at this point call for four trestle
bridges based on the photographs and drawings of the real bridges on
the Kwai. (The movie bridge had trusses, the real ones did not) plus
a plate deck bridge (Kato model) based one of the railway’s
steel bridges in Burma. The problem is for this mountain layout is to
figure out the maximum inclination that can be modeled. The Burma
Thailand Railway steep inclines and in that location two locomotives
were used in a push-pull configuration.