Made a template from dressed timber to ensure correct amount of lean-in, height, and squareness to the longitudinal.

Updated the drawing to include a thicker cross-beam. This did not alter the template outline.

Collecting off-cuts and shavings for future use in diorama. Shaving off excess timber for correct alignment.

One step back too far.

This is going very well.

A couple of observations.

The truss above the roadbed is quite a bit shorter in height than the section below.

Higgins overstated it, but its about a 3 above 4 below.

The verticals in the trusses out board of the main piers are either double logs, or big ones split top and bottom. The latter would suggest the whole thing was a model. 

I don't think in my 40 years of practice I've looked quite so hard at a structural engineering model as I have here, but you are certainly making a model of a model.

GMorrison

This is going very well.

A couple of observations.

The truss above the roadbed is quite a bit shorter in height than the section below.

Higgins overstated it, but its about a 3 above 4 below.

The verticals in the trusses out board of the main piers are either double logs, or big ones split top and bottom. The latter would suggest the whole thing was a model. 

I don't think in my 40 years of practice I've looked quite so hard at a structural engineering model as I have here, but you are certainly making a model of a model.

Thanks, GMorrison, for complement.

Earlier I mentioned that there were three models made for the Magnum PI TV series. One was shown on a previous episode on Higgins bookshelf, which I think is shown below in image (1). The second (2) was made where Higgins actually is filmed gluing matchsticks in place. After filming, the piece was quickly taken off and cleaned up, by the builder. The third (3) model was built to be blown-up. Each model looks very different to each other, especially in terms of spacing between trusses.

Here is a photo of the real movie bridge. Notice that the actual trusses on the cantilever are equal top and bottom. What makes it look smaller on top is the platform and railings.

The other problem encountered with the top half is how the platform is built by the modellers.

They are caught out by two building approaches. The first, is that the real railway tracks is built into the platform as opposed to being on top of it.

The other mistake is that the Burma railway uses a narrow gauge. Scale railway, Z gauge, is the closest width (6.5 mm) for the needed 5 mm. However, Z 'scale' (different to 'gauge') is 1:220 as opposed to the 1:150 I am using. Hence a small train indeed.

That is why I am not going to present a train in this build, at the scale I am using.

Created a second template to fit in between the piers. The card also shows me which sets of piers have supporting horizontal braces.

PeterPan

The other mistake is that the Burma railway uses a narrow gauge. Scale railway, Z gauge, is the closest width (6.5 mm) for the needed 5 mm. However, Z 'scale' (different to 'gauge') is 1:220 as opposed to the 1:150 I am using. Hence a small train indeed.

Scale and Rail gauge get complicated quickly.  Full-size rail gauge is around 4'-8"; or 56", or 142-145cm.  The pre-made rail scales all "want" a nice even number of millimeters between the rails to represent the scale.  Which is handy bfor casting rail sections.  But, less so when 1 meter, 2' and 3' rail gauges have been used.

The narrow-gauge model railroaders are a dedicated and committed lot, and many have "workarounds" to achieve their ends.  In your case, you'd probably have to handspike rails (so that the sleepers would be the right size).  But Z guage trucks under N gauge body work would get a result.

Probably simpler to let the work stand for itself, instead.

And, getting the right rolling stock would be very very difficult.

My last big layout included a narrow gauge/ standard gauge interchange. I did use Z gauge (1/220 if used as standard gauge track, more or less 1/160 if used to represent 3'-0" guage.).

I scratch built the cars as they were oil transport cars- flatcars with rows of wooden barrels on them. Z trucks.

Needless to say there was no locomotive on the slim gauge.

Judging from the DB locomotive there in "Die Brucke", the Germans beat the Japanese in 1947 and won the war outright.

Thanks Mac for excellent explanation and information. I figured the narrow gauge used was about 33". Compare Alec Guinness height to width of track in previous images.

CapnMac82

...

Probably simpler to let the work stand for itself, instead.

I totally agree with you. If anything, at least a home built flat car, as GMorrison suggested, but loaded up with a few tracks and sleepers to finish the bridge off.

GMorrison

...I scratch built the cars as they were oil transport cars- flatcars with rows of wooden barrels on them. Z trucks...

Thanks for the good idea.

GMorrison

Judging from the DB locomotive there in "Die Brucke", the Germans beat the Japanese in 1947 and won the war outright.

If that was the case . I don't think I would be here.

PeterPan

Thanks Mac for excellent explanation and information. I figured the narrow gauge used was about 33".

One of those tidbits I picked up along the way.  In my Amphibious days, I got to work with PhibCB (Amphibious Construction Battalion) types.  One of their beachhead exploitation methods involves setting up impromptu narrow gauge railways, typically 2', but sometimes 1 meter, often based on whether local lines were one or the other.  So, part of the logistics planning involved knowing what sources of rails would be near the beach (the less you carry over the littoral, the better).

I've also had to priveldge of knowing a few avid model railroaders.  And the American west historically used a lot of 2' and 3' narrow gauge for lumber and mining operations.

Narrow gauge rolling stok has a unique look to it, the sides of all the parts overhang the wheels and trucks considerably.  Locomotives particularly so, as you still need a fireman and an engineer to drive the thing, and you need room to put fuel in the firebox.  Our most excellent GMorrission can probably better speak to this.

33" would be 83-85cm, would be interesting to know if that was a narrow gauge used in Asia.

CapnMac82

...

33" would be 83-85cm, would be interesting to know if that was a narrow gauge used in Asia.

Hang on a minute, Mac. Don't forget we are talking about the movie bridge, which was built in Ceylon (Sri Lanka).

PeterPan

Hang on a minute, Mac. Don't forget we are talking about the movie bridge, which was built in Ceylon (Sri Lanka).

Which does not make sense, since Ceylon used broad gauge (5'6").

https://en.wikipedia.org/wiki/Sri_Lanka_Railways

Besides. I doubt there was a nearby railway line where they built the movie bridge. They may have done one of two things. 1) copied the Burma/Thailand gauge of 1940s, and shipped in a locomotive of old to fit on it. Or 2) used a narrow guage mining, or logging, or sugar cane rail guage, of Ceylon with its own locomotive.

What do you think?

PeterPan

What do you think?

I believe you are on to something there.  The movie had working rolling stock for at least some of the footage.  So, that was likely re-purposed from some plantation or the like, as it very much has the "skinny" base look of narrow gauge.

Now, the movie set was complicated--at least from the notes on it it I have seen.  The full-size bridge was only needed for a few shots, and in only limited perspectives.  The bridge that had the pyro on it was a model, but no one has hever sussed out what scale (legacy of earlier days, when there was no market for such minutia).

I would not be surprised if they used 1/8 scale (1 1/2" = 1'-0") as there were live-steam narrow gauge kits available in that size, which the props & effects crew could have ginned up.  1/8 scale would be small enough to managable as a set piece, yet big enough to not have too many issues with how neither fire nor water "scale."

But, that's my 2¢, t'pence, to be oldfashioned (I hava 2d coin from Australia my father brought me home as a gift, and no, I'm not parting with it, or the farthing, either ).

Actually the movie set used a real full sized steam powered narrow gauge locomotive and cars according to wiki.  The bridge was to be blown in front of the PM of Ceylon, but a cameraman wasn't able to get out of the way in time, the run was aborted and the locomotive ran into a generator across the river.  The locomotive was repaired for a next day shoot.

richs26

Actually the movie set used a real full sized steam powered narrow gauge locomotive and cars according to wiki.  The bridge was to be blown in front of the PM of Ceylon, but a cameraman wasn't able to get out of the way in time, the run was aborted and the locomotive ran into a generator across the river.  The locomotive was repaired for a next day shoot.

 

Bravo. That is true.

https://www.bing.com/videos/search?q=Bridge+on+river+kwai+explosion&&view=detail&mid=62ACE8053529CD46F21762ACE8053529CD46F217&&FORM=VRDGAR

Here are some interesting shots:

Charges going off, including the one at the tower base.

The train and narrow gauge used.

CapnMac82

...Now, the movie set was complicated--at least from the notes on it it I have seen.  The full-size bridge was only needed for a few shots, and in only limited perspectives.  The bridge that had the pyro on it was a model, but no one has hever sussed out what scale (legacy of earlier days, when there was no market for such minutia).

I would not be surprised if they used 1/8 scale (1 1/2" = 1'-0") as there were live-steam narrow gauge kits available in that size, which the props & effects crew could have ginned up.  1/8 scale would be small enough to managable as a set piece, yet big enough to not have too many issues with how neither fire nor water "scale."...

Sorry Mac, but I have to disagree. The movie bridge location/site, these days, also has people visiting what remaining parts of the train carriages they left there in the water.

Here is a screenshot from the movie...

and here is a photograph of th actual movie bridge...

Peter, I found 2 sources that state that the length of the bridge was 425 feet and was 90 feet tall.  Hopefully your dimensions are close to that with your using of forensic comparatology.

PeterPan

The movie bridge location/site, these days, also has people visiting what remaining parts of the train carriages they left there in the water.

Dang, "golden age of film" going full size and blowing it all up, too.

I'll sit corrected, then.

Not unprecedented, naturally--they built a 7/ scale replica of Titanic for that movie--makes me wonder what happened to that.

richs26

Peter, I found 2 sources that state that the length of the bridge was 425 feet and was 90 feet tall.  Hopefully your dimensions are close to that with your using of forensic comparatology.

No, I failed in that quite misearably.

I estimated the bridge to be about 400 feet by 68 feet.

Earlier, I re-drilled the outer holes to make it a bit easier to slant the piers inwardly. A few holes actually cut into the larger base board. This sunk the pier further than I wanted it to. While pondering what to do, Minder (my alter-ego) came up with a solution.

Bridge trusses completed.

This is looking good.

Your original drawing, and the movie stills, show sloping banks at each end under the trestles. But you're building the trestles with all of the bents full height on a flat base.

Are the banks still in the plan, and are the trestles going to be standing on them?

The usual method is to build the roadbed on something that can span the full distance from end to end, or in this case from solid earth to the first tower. Then build each bent to length per your drawing and suspend them from under the roadbed. Fill in the grade under them and hide the bases of the poles with ground cover.

PeterPan

The train and narrow gauge used.

And I wonder why did they use merchant marine flags on that engine - it probably has sailors going for R&R onboard :-)))

Have a nice day

Paweł

As soon as one is brave enough to admit an error, others feel safe and empowered to push the point.

GMorrison

This is looking good.

Your original drawing, and the movie stills, show sloping banks at each end under the trestles. But you're building the trestles with all of the bents full height on a flat base.

Are the banks still in the plan, and are the trestles going to be standing on them?

The usual method is to build the roadbed on something that can span the full distance from end to end, or in this case from solid earth to the first tower. Then build each bent to length per your drawing and suspend them from under the roadbed. Fill in the grade under them and hide the bases of the poles with ground cover.

I prefer to secure piers into the base, then fill in the land within and around the structures, like I did with the Wardell Bridge project. I am relatively new to dioramas, and I think I am blessed to not follow the norm to end up doing the norm. I rather rely on what I already know, even if it seems a whole lot of madness.

Pawel

PeterPan

The train and narrow gauge used.

And I wonder why did they use merchant marine flags on that engine - it probably has sailors going for R&R onboard :-)))

Have a nice day

Paweł

Don't know about that. Cinematography tends to no worry too much on accuracy, but on impressions. That is why the movie bridge is inaccurate to the real.

Looking amazing to me! 

I can't even finish a simple kit out of the box and you've finished one giant bridge diorama and are starting a second one... 

Gamera

Looking amazing to me!  I can't even finish a simple kit out of the box and you've finished one giant bridge diorama and are starting a second one... 

Amen...

Thanks Gamera, and Bakster.