The Bridges at Saltash

Post details of your T gauge layouts and the progress you are making.
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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

No pressure, then! ;)

Unfortunately, as you may have picked up following my build threads, I do tend to jump from one thread of a build to another.....so results on my point may not be that quick. But seeing as there is a bit of an interest, I'll try to put a little more effort in on the point build in the next few weeks....
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

Pushing on with yet another different aspect...the flexi-traverser....which I've partly made whilst the idea is still reasonably fresh....

The flexi-traverser is basically an oversized point that consists of three parallel tracks attached to rotational slides at each end that move a single track width in a similar way to a point....here's a couple of photos: First...the full traverser
IMG_3294_red.JPG
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You can see inside the basic box are two strips of wood that pivot half way across at the extreme end of the box. At the other end, there is an arc shaped slot in the top of the box....into which fits a sliding panel that is mounted on the wood strip. Here's a close-up of one end:
IMG_3295_red.JPG
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The lowere strip inside the box is pivoted at the other end and the panel will be screwed onto it's edge. A servo will then move the panel side to side to move the three parallel tracks so that two of the tracks line up with two tracks at the end. The servos are driven from the CBus control system......at least that's the plan!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

I've not posted anything directly on this thread as I've been concentrating on the DCC side of things which I've been documenting in another thread
( http://www.talkingtgauge.net/viewtopic.php?f=10&t=525 )....so I thought it was time to bring things up to date here as a sort of pre-Christmas progress report.

DCC & automation.....as per the above thread, I've got the electronics of the layout as far as I can go for the time being. The next step is to finish the installation of the LDR sensors and general connection wiring, which can't be done until I get the layout itself moved on considerably.

Tamar Bridge......I've started moving on with the design and printing of the bridge components and bits for the vehicle drive system. The motor drives and controllers/power supply have been obtained and just need fitting when appropriate.

Royal Albert Bridge....nothing started yet, although I may start looking at some of the basic structural pieces after Christmas.

Layout board....I've purchased timber to make the layout board sections, and have started making up the three main sections. This will be followed up by the side and rear extensions. Once all are done, I can start looking at the track bed for the public and behind-the-scenes sections. PVC sheeting similar to that I used to simulate water on The Bridge is on order and hopefully may be fitted over Christmas. Bit of a contrast in the cost of things....15 lengths of 2x1 £13.50.....3 sheets of PVC sheeting £60.00. :shock:

Scenery.....obviously, nothing started as there's a small issue of there being no layout boards.

Trackwork.....I have the basic form of the flexi-traverser assembled and working. I still need to add the short track ends and finish off the guides for the moving sections. I also have the starting work done for the single shallow wye-point that sits at the west end of the rail bridge...I think I've documented this in a separate thread.

Buildings.....I've started by creating a design and print log for the houses and other buildings on the layout....but as of yet, I've not started any CAD work on any.

As with The Bridge, you can see I have several thing in progress at the same time......something I call "Organised Chaos!". I love it! ;)

I'll try to print some progress photos over the next few days.....
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

A few photos as promised...

Layout board partly made...here's the three main sections with the rear behind-the-scenes section in place, with the flexitraverser in its approx. position:
IMG_3320_red.JPG
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A closer view of the flexitraverser:
IMG_3322_red.JPG
IMG_3322_red.JPG (121.47 KiB) Viewed 13335 times
And a selection of parts of the Tamar Bridge:
IMG_3324_red.JPG
IMG_3324_red.JPG (125.08 KiB) Viewed 13335 times
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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Nutter
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Re: The Bridges at Saltash

Post by Nutter »

looks horribly clean and tidy to me :roll:
At least you now know how much room you have and can do the test stretch across the boards to make sure you can reach everything safely.
Mike
DON'T knock it at least I am trying to do something, with only one good hand.

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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

Decided to get to a significant point for another of the manufacturing threads before the New Year....the production of 3D printed buildings.

Here's the first of many:
IMG_3328_red.JPG
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And its the most notable of the buildings...the Union Inn:
Union_Inn.JPG
Union_Inn.JPG (55 KiB) Viewed 13247 times
I'll need to finish this building with a transfer to get the required image resolution.....

One down......many more to go!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

Now I've got the basic baseboards in their 99% finished form....all surfaced and break down-able for transport/storage, I thought I'd start the new year with a dry assembly of the parts I've so far produced:
IMG_3330_red.JPG
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Not bad for less than six months work.

The greatest progress is on the DCC and control system. The six boxes are in approx. their final positions....there's just a wiring harness and individual wires to each track section and sensor, etc to do. The next chunk of work has been on the Tamar Bridge and the vehicle drive system. This is totally untested and unproven.....so I've got a lot to do. The other parts are the flexi-traverser and a half-built wye point.

I'm going to have to take all this to bits and pack everything away soon........I have The Bridge to sort out for it's next show in less than two weeks!!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

At last.....a bit of Brunel's bridge:
IMG_3333_red.JPG
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Its not in its final form yet, but this is one of 17 sections of the approach viaducts. It seems Brunel hadn't heard of standard sized assemblies; two of the sections are 93 ft long, two are 88ft 6in, two are 78ft, two are 72ft 6in, and the remaining 9 are 63ft 6in long...and one of those is wider at one end to allow for the pointwork! And the differing sizes aren't even steps of equal amounts!!!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

Back in April 2014, I posted a shot of a couple of viaduct sections for the Forth Bridge sitting on top of a stone pillar (post here: http://www.talkingtgauge.net/viewtopic. ... 3&start=12 )

Here we are, almost four years later and I'm posting an equivalent shot for Brunel's bridge at Saltash.........
IMG_3336_red.JPG
IMG_3336_red.JPG (86 KiB) Viewed 13149 times
Doug Kightley
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Re: The Bridges at Saltash

Post by dkightley »

I've been able to make some good progress over the past few days......

I now have all of the deck sections and under deck sections for the Tamar bridge all printed ready for the next stage....clean up and assembly of the full deck. The whole bridge will need to be one giant sub-assembly, so this will be the first time I get to see how "giant" it will be!!!!

I've moved on the CAD design of the approach viaducts for the RAB (Royal Albert Bridge). I've put together the individual deck sections....which vary in length...to form two deck sections for each end. The Plymouth side decks are ready to print, as is one of the Cornwall side sections. The other section....the one that joins up to Saltash station....is complicated by the fact that there's a point that sits on the last two sections. More on that below....but here's a picture of an early print of the section, held up with three of the stone supports:
IMG_3339_red.JPG
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So I can assemble the bridge onto the layout, I've had to make all bar one of the stone pillars in two slot-together pieces, and I've got all the CAD work done for these. Included in this set is a support for the very end of the Plymouth viaduct....which also will have the plywood track bed fitted onto it. So....a bucket full of pieces to print here!

I mentioned the point. Back in November, I posted an early state of the point on a printed jig. Now I know what the constraints of the volume into which I can build the point and its control linkage & power supply wires, I've re-done the jig so I make sure it'll fit once I get the point working. Here's the revised jig:
IMG_3343_red.JPG
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The two sections of viaduct shown represent the two sections that the channel shape replace. Fortunately, there's a deeper girder section for these two sections...and they taper. This makes it possible to actually get the point working!!
Doug Kightley
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Re: The Bridges at Saltash

Post by dkightley »

I've been pressing on with things since the last update....in between taking The Bridge to Stevenage and other things.

The most progress has been on designing and printing a range of quick-release posts for supporting the track behind the scenes. As I'm wanting to pack the layout for transport in as small a volume as possible, I was not wanting the track supports to stick out underneath the track bed sections, or on the base board, so my removable quick release posts were born. Here's a photo of a selection:
IMG_3353_red.JPG
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Front row, left to right, the bottom latch section, the post, and the top latch section. The top and bottom sections will be fixed to the base board and track bed respectively. The post section is dropped into the bottom latch and the track bed positioned and the top latch dropped onto the post. A 45 degree twist of the post, aided by the small tab, will lock things tight!

And here's a wider shot showing a few in approx. position...along with some of the fixed supports that will get incorporated into the scenery groundwork:
IMG_3357_red.JPG
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I'm also progressing well with the design of parts for the Royal Albert Bridge. I've completed CAD work on the viaduct supports and have started on the main towers. Once I get these done and draft parts printed, I will then be able to print a draft of the rail deck, so I'll then be able to mark out and create the track bed sections and start fitting them to the base board. Here's a photo of a few of the viaduct support parts:
IMG_3356_red.JPG
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The bottom parts of the support will be submerged in the scenery, with the top sections plugging when the viaduct is assembled .

I've moved on slightly with the development of the wye point for Saltash station. I'm ready to start cutting and shaping the moveable track sections. I've worked out the arrangements to get the right power to the right bits of track for the two point positions. I'll be using either an microswitch to switch power around on the frog & moving rails...although I'm looking at an electronic switching option as an alternative!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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Re: The Bridges at Saltash

Post by Nutter »

good to see the progress Doug.
Waiting on the updates on the Point :D :roll:
Mike
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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

Here's a screengrab of the current state of the CAD for the Royal Albert Bridge, showing for the first time the iconic shape of this bridge:
RAB_Span_CAD_240118.JPG
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So that I can start setting out the track layout, I'll probably print unfinished versions of the bridge track bed and towers so I can do a dry assembly to get positioning right.
Doug Kightley
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Re: The Bridges at Saltash

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I had to post this photo of a dry assembly.....
IMG_3362_red.JPG
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And midst all the excitement about points, here's the current state of my custom point at Saltash:
IMG_3363_red.JPG
IMG_3363_red.JPG (59.76 KiB) Viewed 12036 times
The plate in front sits a bit too tightly under the rails at present.....but will be operated by a lever running to underneath where the two brown track joiners are...and will be operated by a servo.

The thin and long profile of the girderwork has somewhat defined how the point will work. Not bad considering there'll be fresh air underneath all the way along this section!
Doug Kightley
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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

After having attended a regional meeting of MERG over the weekend, I've now made some progress on the control panel design for the DCC automation software....which is called JMRI.

Here's the track layout panel:
JMRIPanel.JPG
JMRIPanel.JPG (53.7 KiB) Viewed 11972 times
The track path is shown in red where sections are occupied, and the simulated LEDs are train detectors for pinpointing the exact location of trains. The above schematic has been rigged to indicate three trains on the layout; one on the bridge travelling away from Saltash (note the point setting gives a hint of direction), one on the branch line (direction not indicated....so what!), and a third sitting on the flexi-traverser ready to head over the bridge after the train already on the bridge has cleared the single line section.
Doug Kightley
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Re: The Bridges at Saltash

Post by dkightley »

Some visible progress at last......

For the first time, I've been able to dry assemble the whole bridge....so I can see if it will all fit together, and make sure I'm happy with the way it fits together and comes to bits, particularly as the layout is designed as an exhibition layout!!

Here's an overall shot:
IMG_3395_red.JPG
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Cornwall to the left, and Portsmouth [EDIT]..whoops, Plymouth[/EDIT] the other side of the wardrobe doors! The two main spans you see in this shot are not the final parts....they're just temporary deck sections I printed purely for sorting out placement.

A closer view of the Portsmouth [EDIT]..whoops again, Plymouth[/EDIT] side:
IMG_3399_red.JPG
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Only seven sections of viaduct this side. The last support also holds the 5mm ply track bed.

And a closer view of the Cornwall (or Saltash) side:
IMG_3397_red.JPG
IMG_3397_red.JPG (82.11 KiB) Viewed 11897 times
A few more sections this side....including the left-most two sections that hold the custom point where the single line track splits to go into Saltash station.
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

msimister
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Re: The Bridges at Saltash

Post by msimister »

Looking good Doug. Er, well yes, Portsmouth but Plymouth is closer...

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dkightley
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Re: The Bridges at Saltash

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With the DCC side of things now back on track....( I'll have to stop using that pun! ;) Its not funny any more.... :lol: ), I'm pushing on with starting to fix down the piers for the Royal Albert Bridge. I've just finished printing a set of pins that will push through the top of the layout board sections from below and locate into mating holes in the bottom halves of the viaduct supports.

Hopefully by the end of tomorrow (Friday) I'll have got to the point where I can start marking out the ply for the track bed.
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

gbtrains
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Re: The Bridges at Saltash

Post by gbtrains »

Hi Doug

That looks great .

Keep up the good work.

Reagrds
Graham :D

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dkightley
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Re: The Bridges at Saltash

Post by dkightley »

After a decision I've recently made, progress on the build will probably slow down for a month or two as I turn my attention to a DCC upgrade on The Bridge, which I have decised to carry out to speed the process of getting an exhibition layout that utilises DCC.

Despite the above, I've today cut out the first of the ply track bed sections that will go "behind the scenes". A twin track section that makes up almost 75% of a complete loop!!!
Doug Kightley
Webmaster here and volunteer at the National Tramway Museum http://www.tramway.co.uk

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