Blea Moor

[martink]

And so it begins...

I have spent the last 3 months considering and evaluating many different concepts for my next layout, in both T and N, and have finally settled on the highly original idea of Ribblehead (in T). To try and preemptively reduce the confusion with the two other Ribblehead threads, for the purposes of this forum I am calling mine Blea Moor. Although it will probably end up being called Ribblehead elsewhere.

The detailed design is still in flux, but the overall concept has settled down nicely.

Serious construction is scheduled to start in December.

The top level requirements are:
- a new exhibition layout, aiming for a first public showing in August 2018
- single-handed setup and fully automatic operation
- at least 2 trains in motion in the visible area most of the time
- as large as practicable, given transport and running-at-home constraints
- a narrow thread of railway lost in a large landscape
- no points
- few trees and buildings.

The main design features include:
- the visible area extends from the overbridge just beyond the Blea Moor loops through to the overbridge at the far end of Ribblehead station (2500m straight line or 2800m along the track in real life).
- two block posts (Blea Moor and Ribblehead) for train control, so 2 trains will be moving and up to 4 will be visible most of the time
- the layout will be a double track oval with no points, with half the track behind the backscene. Sidings and loops will be dummies. The Blea Moor loops will be designed for upgrading with working points if a decent product ever eventuates.
- the time period (for track plans, etc.) is not fully defined, but set prior to the line closure attempts, with loops at Blea Moor, double track over the viaduct, and either one single or two staggered platforms at Ribblehead
- built on either 3 or 4 baseboards, 5'-6'6"" x 2', with a total frontage of 16'-18' (final configuration still TBD)
- overall size and configuration as close to the prototype as possible, though probably requiring 10-20% length compression of the non-viaduct sections and curve straightening of the non-viaduct sections
- a curved baseboard design to support the 80 degrees of curvature over this stretch of track (although reduced to around 60 degrees by the compression), with viewing from the inside (east). This maximises the radius of the 180-degree curves at the ends, and allows me to set the layout up in the corner of a room at home for testing.
- minimum curve radius of at least 10" for the 180-degree curves, with negative super-elevation to try and keep long(ish) rakes of 4-wheel wagons on the track
- no gradients. The prototype gradient varies between 1 in 100 on the viaduct to 1 in 300 in the stations, but this will be ignored for simplicity and maximum train lengths.
- the control system will be a further upgrade of Sarum Bridge's, with independent control of each track, more than 3 trains per track, back-EMF feedback and anything else I can think of.
- all (or most) structures 3d printed by me.

A rough preliminary sketch of the design (Google Earth, slightly compressed in GIMP):

Preliminary Board Design for Blea Moor

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Nearly-final CAD shots of arches for the viaduct:

Preliminary Arch Design

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An early work-in-progress CAD shot of a king pier:

Preliminary King Pier Design

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More to follow as events progress!

[Nutter]

Looks like Bridges are the in thing at the moment.

[msimister]

So you're aiming for Melbourne's big exhibition at Caulfield next year? (For others, Warley it ain't). Look forward to seeing it.

[dkightley]

This will be the second 3D printed model of Ribblehead that's been made for T Gauge. The previous one, which is featured on one of the Ribblehead threads, I supplied in good faith...and they went incommunicado and haven't paid me for it! No idea what happened.......just had to put it down to experience!

Despite doing what I did...which I regretted....ie promised it would be ready for a show.....I hope you fair better and get it completed in plenty of time...and not like me, during the set-up for the show!

[martink]

A bit more progress - now ready to start on the timberwork.

The size has settled down to 4 identical wedge-shaped (trapezoid) boards, 4'9" along the front (viewing) edge, 5'6" along the rear edge, and 24" deep. They are effectively arranged on the outside of a 12' radius circle. Each is just a bit bigger than all of Sarum Bridge. The four boards together form a 90 degree curve with a viewing frontage of 19' (6m). This is basically the maximum size that I can squeeze into the car in a specially-designed transport frame, manhandle by myself, and fully assemble and test at home. It works out to about 85-90% of the prototype size, or close enough for government work.

A 3D printed model of the model, at 1:25 scale (1mm=1inch), or 1:11250 of the real thing...

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The model of the model packed into its model travelling frame for the back of the station wagon (not modelled)...

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[martink]

After spending a good 6 weeks bludging over the holidays, I've finally got back to work on Blea Moor, resuming at the start of February.

One major design change: the viewing side is now the outside of the curve. This took a bit of juggling, but improves a number of areas.

As planned, the visible section of the layout starts from the occupation overbridge at the north end of Blea Moor, runs along the embankment and Ribblehead viaduct, and ends with Ribblehead station through to the (now demolished) occupation overbridge at its south end. Other than the stations and loops, all on a 1.6km radius curve. That all works out to an 18 foot stretch of visible track, or 2.5km. The prototype is 2.9km long between those bridges, so the model is 85% of full size. Alas, I cannot fit in the extra 3 feet it would take to do it at 100%. Fortunately, it is all open country, so the compression won't be obvious.

The four baseboards are now built, and after several false starts it seems I will be using trestle tables for support again instead of legs. That gives me various options for adjusting the height for construction and display. The layout just barely fits into my lounge room for setup and testing. It is currently there with a mockup of the visible track bed, with Ribblehead station on the left and Blea Moor on the right. While almost invisible, there is actually a full-length HST on the viaduct!

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[zdrada69]

Impressive !

[martink]

Peripheral work for the layout is progressing slowly, in dribs and drabs, but there are a few new things to report...

I have always found making the legs for a layout to be a real problem, especially with small transportable designs. It is easy with a fixed home layout - just make them really solid, heavy and well-braced. Portable layouts raise all sorts of transport, stability and height issues. So, I think I have finally found a general solution that I intend to use for this and all future (and past) layouts. Steel folding table bases are sturdy, stable, pack neatly into the car, and the height can be adjusted by adding timber extensions. Blea Moor now has a designed track height of 1050mm, but this can trivially be altered if circumstances require it.

The four baseboards and legs fit neatly into the back of the car, using the old trick of bolting each pair of boards face-to-face with plywood sheets to make two packing crates. The leg-height extenders are visible, and the table bases are packed in there too (although invisible as black-on-black).

Also, the details of exactly what gets squeezed onto the layout are nearly final, looking at backscene and elevation data now, and almost ready to build the track bed. It is all to scale except for the Ribblehead station area, which is somewhat compressed.

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