Non Railway Modeller Needs Help, Please...

[G-man69]

Hi all,

 

You have kindly helped me out on two questions posted previously within this topic, both related to small dioramas (A4 footprint) in 4mm scale, both set during WW2.  The first being possible sources of implements/items to ‘dress’ a ‘farmyard’, the second being the type, and suppliers, of rolling stock suitable for a quayside setting…now nearing completion (see image below).

 

 

Now I'm aiming to create another A4 size diorama using up the track left over from the above scene.  Again, it'll be set during WW2, but this time will incorporate a railway bridge passing over a canal an acute angle, as opposed to 90 degrees.

 

I therefore have two questions:

 

Firstly, would the bridge supporting walls be parallel to each other, but not to the banks of the canal, as in the left-hand sketch below, thereby allowing a square built bridge to be built across the span, or…

 

…would the bridge supporting walls be parallel to the canal banks, as in the right-hand sketch, thereby requiring the construction of an angled bridge across the span?

I hope the above makes sense?

 

Secondly, does anyone know of a site(s) where I can obtain detailed construction details and dimensions for a steel plate girder type railway bridge?  The kind of dimensional information relates to overall width for a single track, or possibly double track line, including clearances either side.  Size of supporting beams and how they would be braced together, size of sides/parapets, and whether the base would be ballasted or planked…basically anything that would allow me to scratch-build the item.

 

If anything is unclear and/or anyone has any questions, please feel free to ask away.

 

Cheers, 

 

G

[SR71]

Hi G,

 

That's a challenging one. I've seen your second option more commonly but have also seen your first option. It will depend on when it was built and by whom (which regional railway company) etc.

 

Steel designs will again be subjective. I would say if you can be more specific on region then people may be able to point you towards reference photos. I took some recently here;

 

 

But I didn't note the construction date unfortunately.

[Andy Hayter]

Defining location is key.  If this is France like the original ideas, then be aware that canals are significantly wider than the UK.  

 

As above parallel parapets is much the more common arrangement.

[G-man69]

Thanks to both SR71 and Andy for confirming that my second sketch is more likely to be the type encountered,.

 

Thank you for the link to your photos SR71, the first ones give me some idea of how the framework looks, much appreciated, .

 

The bridge/canal will be WW2 era, and UK based, I had been toying with an idea of a fictional area in the south-west, maybe along one of the 'stop lines' built to hinder the Germans if they invaded...but never too proud to ignore the ideas of others.

 

Cheers,

 

G

[Nick C]

If you want something more unusual, along that theme, how about this bridge over the river Arun:

 

https://en.wikipedia.org/wiki/Cranleigh_line#/media/File:Rudgwick_Double_Bridge.jpg

 

It was part of one of the defensive lines, which followed the river ( https://edob.mattaldred.com/map/S0016648 ), and is still extant, with the Downs Link path running over it along the former railway.

 

Alternatively, there is another bridge on the same branch, crossing the Wey Navigation (and the outer London defensive ring), which fits more with your previous sketch: https://edob.mattaldred.com/map/e25061

Edited February 23, 2022 by Nick C

[RJS1977]

There are two types of girder bridge - underslung (where the girders are beneath track level) and overslung (where they come above track level).

 

On overslung bridges, the girder doubles as the parapet, and its size is dictated by the length of the bridge and the weight of the trains using it.

 

On underslung bridges, the parapet (if there is one - some just have handrails) serves no structural purpose and is really there to stop workmen falling off the bridge, or possibly to catch an occasional derailment. As such, they'd be unlikely to come much above footplate height.