7mm Pencarrow - Cornish BR(S)

[Pencarrow]

Whilst on the subject of bridges, I find this book very useful. Both for remembering what all the parts are called and having lots of prototype photos. Some of the bridge kit manufacturers would do well to have a copy. They would then hopefully avoid stupid mistakes such as the bridge beams floating in mid air between abutments rather than sitting on them. (Looking at you L-cut Creative)

 

[Osgood]

Going to need another bookshelf....

 

[Pencarrow]

Brick cladding installed under the arch. Now the tricky task of getting the first front arch ring to match...

 

[Pencarrow]

Well, that was fun...

 

[Pencarrow]

Well, that's the trickiest bit done - on this side at least.



The spandrels will need a spot of filler to tidy them up. Buttresses next I think.

 

[Pencarrow]

Best period shot I can find, as ever a small part of a much larger photo. Interesting to see that the 4th row of arch ring bricks goes behind the buttress. The corner blocks look about 15" tall to me.

 

[simond]

Between 4 & five bricks, so 15” smells about right. Nobody is going to be able to tell you it’s wrong, in any case!

 

[matto21]

The brick arch is superb! Individually placed or some other trick?

 

[Pencarrow]

Between 4 & five bricks, so 15” smells about right. Nobody is going to be able to tell you it’s wrong, in any case!

That's what I thought too Simon, between 4 and 5 bricks. Having sketched it out at 15" it seems about right too. The saving grace is that it's only a 'based on' bridge, so as long as it's sound from an engineering point of view, it can't be too wrong.

I've also got the theory about structures and buildings that as long as they look about right, people just accept them and don't really notice the detail. It's things that look wrong that draw the eye.

 

[Pencarrow]

The brick arch is superb! Individually placed or some other trick?

Thanks chap, no real trick just a bit of time consuming work. Each arch ring is cut from a column of stretcher bond brickwork, half a brick wide. The edges of the brick column are slightly chamfered.

The trickiest row is the first one as you need the brick courses of the ring to match the arch lining. Some cuts and adjustment were required as the moulded coursing isn't 100% accurate.

The 2nd to 4th arch rings are much easier but you have to remember to do each course in two halves, starting each side from the bottom and doing some minor adjustments towards the crown to lose any gap. That reflects how the arches would have been built.

 

[Pencarrow]

Starting to look like a bridge now the buttresses have gone on. Will leave them to set before doing any more work.



One advantage of doing the arch ring properly is that you can do shots like this without embarrassment. Well, that will be true once I've done some touching up...



A quick check that the buttresses are vertical before the glue sets ...





Happy with that...

 

[Pencarrow]

We've not really had a whole layout shot for a while. Bit of a mess in places but just realised there's now only 2 structures I've not yet started.



The station building and goods shed are still card mock ups.

 

[matto21]

This is going to be a masterpiece when complete you know!

 

[Pencarrow]

This is going to be a masterpiece when complete you know!

Thanks chap, much appreciated. Only taken 10 years so far, and I sometimes look at it and wonder will I finish it and is it too much for one person. I have however realised it's the journey I prefer rather than the destination, so time taken = task enjoyed.

There is however a growing list of people who have assisted with the project to date including Simon, Mick, Dan, Robin, Paul, Richard and the late, great Gbloke. That's a result of the realisation that I don't have the time of skills to do everything myself, particularly on the kit loco front.

The growing number of RTR models is a big help in the last respect, but it is very noticeable that all my SR locos (Spam, N Class, T9, O2 and BWT) are not available as RTR. On the other hand ⅔ of the WR and diesel collection are RTR.

Of all the things left to do, those that are going to be the biggest challenges (to me) include:

- the station building, all those stone window surrounds, the stonework and the canopy ironwork.
- getting the double slip mechanically working.
- building a girder bridge to a standard I'm happy with.
- sourcing or making the 100+ windows that are needed to complete various buildings.
- finishing off the wiring, not because it's difficult, but because it's dull. Same goes for ballasting.
- installing all the point rodding. It's drawn up and I have all the parts, but is a huge time sink and oh so fiddly.
- finding time for it all!

But in the meantime, on with the bridge...

 

[simond]

- the station building, all those stone window surrounds, the stonework and the canopy ironwork.
- getting the double slip mechanically working.
- building a girder bridge to a standard I'm happy with.
- sourcing or making the 100+ windows that are needed to complete various buildings.
- finishing off the wiring, not because it's difficult, but because it's dull. Same goes for ballasting.
- installing all the point rodding. It's drawn up and I have all the parts, but is a huge time sink and oh so fiddly.
- finding time for it all!

You do buildings, might take time but it’ll be excellent. Canopy ironwork. Can it be laser cut from Trotec? If it has to be soldered brass, 3DP jigs on a resin printer.

I did a double slip for Ken Stansfield (rip) some twenty years back. I doubt I have the drawings but I recall that the tie bars at each end were equalised to a Tortoise. I’m going to have to sketch it now, as the memory is struggling. I do have a wiring diagram somewhere. The tortoise at one end controls a frog at the other.

I think you’ve already decided that the bridge is going to be brass. CAD Drawings take time, but the rest is a doddle. Put temporary view blocker in place for the time being.

Window frames. Laser cut Trotec. Available in white. Or card, or MDF. CAD Drawings required.

Wiring isn’t dull. Well, maybe running the wires and fitting the crimps, etc., but testing it is always exciting (the loco moves) or very exciting (the wiring catches fire). No, not at all dull.

Point rodding. I reckon that’s a job for when other things are coming together, each session, you can do a bit & play trains. The proportions of “doing” and “playing” are entirely in your own hands. (and I would spend more time playing, personally)

and you’re enjoying the journey!

 

[Pencarrow]

The canopy ironwork is a bit tricky to get photos of as blessed panniers and coaches and railbuses seem to get in the way.

The snip below should give you an idea of the structural form, and I'd welcome thoughts on the best materials. I'm automatically thinking brass for the main structure as the canopy will need to be removable and will be prone to being knocked when leaning over the layout.



I think I am going to bite the bullet on the windows and place an order with York Model Making. I had about 100 off them for an EM project I was involved in about 15yrs ago, and at the time was impressed with the results. They may have been a bit thick for 4mm but the same materials and tolerances should be better for 7mm.

Bridge view blocker... I could put the prairie tank in the gap between abutments? Is that the sort of thing you were thinking of?

Double slip... The structure seems to work fine with stock not derailing when pushed through on all routes. The wiring seems simple, I have a diagram for that, I'm really puzzled on how to get 4 points blades to move at each end. Would welcome thoughts on 'equslising tiebars', and I will be using Tortoise point motors.

Wiring... Never had a fire, had lots of not working but, that said, I do take quite a neat methodical approach to installation and I only gave about ⅓ left to do based on the plan you sent me years ago.

Point rodding... The push there is that I wanted all the supports and bases in place before ballasting. Much easier that way around.

Many of the remaining tasks will need individual boards taking out of the layout so they can be worked on. I'm thinking of knocking up a stand on casters to aid with this work.

 

[Heather Kay]

Although it’s hard to see in that photo, the canopy support structure reminds me a lot of Swanage. It's very likely standard across the network.

 

[Pencarrow]

Although it’s hard to see in that photo, the canopy support structure reminds me a lot of Swanage. It's very likely standard across the network.

Hi Heather,

It's similar in that it uses columns supporting a lattice beam but the lattice at Swanage seems to be simpler (later and more efficient?). The Bodmin North example seems more ornate and decorative, with the lattice horizontal L prices being separate and presumably rivetted or bolted together.



I think the example at the restored Wadebridge station is probably a closer match (but not as deep), but sadly a fair few miles away to measure up just now. That said, the good lady wife was asking about whereabouts I'd like to go on holiday this year...

Google Image Result for http://www.disused-stations.org.uk/w/wadebridge/wadedbridge(1.2000)7.jpg

 

[simond]

It’s saying “brass” to me. I think you could solder up the diagonal braced girders quite easily. I guess there are triangular angle iron frames above, supporting stringers which in turn support a planked roof? These triangles too could be soldered up on 3DP jigs. Might want some etched corner plates, etc., but if there aren’t many, you could probably fret them.

you might want to talk to Barry at Metalsmith, he has all sorts of lovely brass angles, and tees.

the pillars can be brass tube let into sockets in the platform. The decorative castings can be 3DP top & bottom.

no fires. That’s good…

I’ll see what I can find re double slips.

 

[Pencarrow]

All 4 decorative corners, quoins, now done.



Some post blending and shaping will have to be done, but some initial texture added by running solvent over the surface and then going over with a wire brush. Yes l, I'm abusing tools again...