How can I identify what is needed to build this two road tunnel in N Gauge/2mm

[Royal42]

I have three tunnels to build for my 2mm/N Gauge diorama and one of them is proving difficult to identify what type to construct. 

This view shows a large iron bridge tunnel on the left, a single track, with turnout, arched tunnel in the centre and a girder bridge on the right.  I am struggling to identify the design of the arched tunnel in the centre.  I am not even sure whether it is a single or two road tunnel.

 

 

The track is single but splits on entering the arched tunnel.   I don't think the tunnel facade crosses the tracks at right angles; also, I'm not sure how to define it for building.

 

 

The small platform, above and left of the tunnel entrance, plus the signals, are complicating my view and I could do with help on any clues or advice please.

 

I have been buying Scalescenes card models for my diorama but this shape doesn't seem to match anything available.

 

cheers,

Mike

Edited April 18, 2021 by Royal42

[Darius43]

All three structures are bridges rather than tunnels.  The “large iron bridge” is a deep plate girder bridge, the depth being required to enable the long clear span.  The central bridge is a masonry (brick) arch with a relatively flat arch profile, hence the heavy masonry piers (“platform”) on either side to take the lateral thrust forces from the arch.  The shorter span bridge on the left is of shallow girder construction with a masonry parapet.

 

Unless Scalescenes produce a kit for the pre-war New Street Station road bridges in the near future , I am afraid you will have to scratch build these bridges.

 

Cheers

 

Darius

[Darius43]

If you have obtained the Scalescenes masonry arch bridge files, you may be able to “stretch” the arch sideways using computer imaging software (you can do this in MS Paint) to create the “flatter” arch of the central bridge.

 

The modified image can then be printed out and stuck onto cardboard in the usual Scalescenes fashion.

 

Cheers

 

Darius

[Nick Holliday]

1 hour ago, Darius43 said:

If you have obtained the Scalescenes masonry arch bridge files, you may be able to “stretch” the arch sideways using computer imaging software (you can do this in MS Paint) to create the “flatter” arch of the central bridge.

 

The modified image can then be printed out and stuck onto cardboard in the usual Scalescenes fashion.

 

Cheers

 

Darius

The reason the arch looks so flat is that the bridge is very skewed, so at the end we are looking at a slice through the arch at about 45° to the actual line of the arch.  Stretching the Scalescenes arch will distort the brickwork, especially the spandrel panel above the arch.  I would suggest trying a free programme called BrickArch which allows you to prepare bespoke brickwork designs, within certain limits. The result can look like this:

 

The plain brickwork above the arch has to be cut to fit, but that will retain the brick sizes and coursing you want.

[Royal42]

Thanks Nick and Darius, that's very helpful and informative.  I shall give the stretching a try, plus have a look at BrickArch.

cheers,
Mike

[Royal42]

2 hours ago, Nick Holliday said:

........... I would suggest trying a free programme called BrickArch

Do you have a link for this software?  I did a google but came up with and actual brick building company.

Mike

[Nick Holliday]

Sorry, BrickArch is the title of the exe file, but the download is here: http://www.bwwmrc.co.uk/bricks/index.shtml courtesy of the Beckenham & West Wickham Model Railway Club.