The Bridge

[Vecchio]

Sitting in an armchair with a dram of single malt some time ago the idea was born to try my luck on a Scottish layout. Of course, West Highland Railway line. I will not start immediately in creating baseboards as I usually do. I will start with just one module which I will call the bridge. As the reader may guess - I will try to make a model of the Banavie swing bridge. The material is no question for me, it will be brass Came out too difficult, so polystyrene it is. But before to start I need a few essential things. One of them is a drawing. I have been in Banavie 5 years ago and made many photos, as I was fascinated about this bridge also then. But if you want to build it you need more. Photos taken at 90 degrees to the structure and photos of all details as for instance the service ponton and the stonewalls on both sides of the canal.  With this I was lucky as my wife has planned a holiday near Oban. This holiday took place last week, and we were lucky with the weather. I spent the whole Monday on my own in the area taking photos. Unfortunately, I couldn't see the bridge move, probably because of the Queens funeral there were no boats around. I planned to go there another day, but this didn't happen as from Wednesday onwards I was grounded by some movement of a kidney stone which caused a nice kidney infection.

 

Anyway, I have my photos, the infection is cured for the moment, so I can start with a drawing. But: how big do I want the bridge to be? The original is about 35 meters long, this would lead to 460mm in 00 scale.  Quite large I would say. To keep the track more or less in the middle of a standard 4x2 module the thing shouldn't be much more than 300mm. But how should I scale the bridge down without losing the right look? I can take 2 fields out of the truss bridge, but this shortens it just 4 meters, so we are still at 408mm in 00. I don't want to shrink it lengthwise as the distance between the vertical I beams would considerably change and if I scale down the whole thing the train on it would look oversized. I need to find the right compromise.  any ideas welcome. 

 

To give those who do not know this bridge an idea - find here a (hopefully) 90 degree shot of the bridge, taken from the nearby road bridge. 

DSC_0194

 

And as I was there long enough - the morning Jacobite train from Fort William to Mallaig. 

DSC_0157

 

 

 

Edited January 11, 2023 by Vecchio
change of material...

[Pete the Elaner]

11 hours ago, Vecchio said:

Sitting in an armchair with a dram of single malt some time ago the idea was born to try my luck on a Scottish layout. Of course, West Highland Railway line. I will not start immediately in creating baseboards as I usually do. I will start with just one module which I will call the bridge. As the reader may guess - I will try to make a model of the Banavie swing bridge. The material is no question for me, it will be brass. But before to start I need a few essential things. One of them is a drawing. I have been in Banavie 5 years ago and made many photos, as I was fascinated about this bridge also then. But if you want to build it you need more. Photos taken at 90 degrees to the structure and photos of all details as for instance the service ponton and the stonewalls on both sides of the canal.  With this I was lucky as my wife has planned a holiday near Oban. This holiday took place last week, and we were lucky with the weather. I spent the whole Monday on my own in the area taking photos. Unfortunately, I couldn't see the bridge move, probably because of the Queens funeral there were no boats around. I planned to go there another day, but this didn't happen as from Wednesday onwards I was grounded by some movement of a kidney stone which caused a nice kidney infection.

 

Anyway, I have my photos, the infection is cured for the moment, so I can start with a drawing. But: how big do I want the bridge to be? The original is about 35 meters long, this would lead to 460mm in 00 scale.  Quite large I would say. To keep the track more or less in the middle of a standard 4x2 module the thing shouldn't be much more than 300mm. But how should I scale the bridge down without losing the right look? I can take 2 fields out of the truss bridge, but this shortens it just 4 meters, so we are still at 408mm in 00. I don't want to shrink it lengthwise as the distance between the vertical I beams would considerably change and if I scale down the whole thing the train on it would look oversized. I need to find the right compromise.  any ideas welcome. 

 

To give those who do not know this bridge an idea - find here a (hopefully) 90 degree shot of the bridge, taken from the nearby road bridge. 

DSC_0194

 

And as I was there long enough - the morning Jacobite train from Fort William to Mallaig. 

DSC_0157

 

 

 

 

You'll be wanting as narrow a river as possible, but it would still need to be deep enough for boats to be able to use it. So how about a canal? Corrugated sides may look reasonable.

Most canals fell out of use with taller boats a long time ago, so the swing bridge would need to be low otherwise it would have been replaced by a fixed bridge, which is not what you want to model. This is good because being lower should disguise its shortness a little.

It would also give you an excuse to model the boughs of a couple of boats, waiting for the bridge to swing out of their way again. An operator's hut could also be justified.

[Vecchio]

Dear Pete, a canal it is - as it is the Caledonian Canal, built by Thomas Telford and finished in 1822. As this was quite late in comparison with other canals in the country it is much wider and deeper than a narrow boat canal.  

The design size for the canal was: Maximum boat length 45.72m (150ft), Maximum boat beam 10.67m (35ft), Maximum boat draft 4.1m (15.5ft), Maximum boat air draft 35m (115ft). Today all the locks are hydraulically operated. There is the operators hut for the bridge, it is next to the parallel road bridge. There is also a signalbox in the station of Banavie, which is not only controlling the bridge but a large part of the Western Highland Line (therefore it looks rather big for such a small halt as Banavie is). 

 

Let's have a look at the other direction, here you see both bridges and a very small corner of the control building (right edge of photo). In the background you see the locks of Neptune's staircase (8 locks in total)

DSC_0131 

 

This is the complete control building which is responsible for both road and rail bridge. 

DSC_0171 

 

And finally the Banavie signal box. It is just a few yards from the bridge, at the end of Banavie station platform.

DSC_0147

[PerR]

The 35 meters is that the total of the bridge or just the overhang on the canal?

 

On the pictures I see the the turntable underneath the bridge. If the total of the bridge is 35 m, then the turntable is about 10 m from the end and the overhang on the canal «only» 25 m. 

Then you will need space to turn the overhang on 25 m and not the entyre 35 m. Or am I missing something here…?

 

The canal is also in an angle to the railway. This will be to your favour if you model the bridge with a view from the loch-side.

 

It is a beautiful place you have chozen - good luck and best wishes! 
 

 

[Vecchio]

The 35 metres is the total length of the bridge. 

Thanks for the wishes, will need them!

 

[PerR]

Then it is the overhang you need space for; 25 m = 32,89 cm in scale.

 

If you, as you mentioned,  compremize on the total lenght of the bridge and shorten it by max 4 meters, and model the canal in the prototypical angle to the railway, you will manage to be marginally within the width of the board.

[trevora]

38 minutes ago, PerR said:

The 35 meters is that the total of the bridge or just the overhang on the canal?

 

Surely the canal takes boats Maximum boat beam 10.67m (35ft), 

so the part over canal must be atleast that

 

 

 

[PerR]

10 minutes ago, trevora said:

 

Yes, and I look at the first pic in post 1, and count the fields in the truss bridge. I count 7-8 fields in the part of the bridge overhanging the canal it self. One field is about 2 meters if the bridge is 35 meters in total, and that makes the part of the bridge over the canal about 15 meters.

[Vecchio]

A little bit of progress. As the shape of the bridge side doesn't follow any geometric figure I draw it as a spline curve. Which is annoying as my CAD program doesn't accept intersections with this curve...

 

I was also successful on the rolling stock side; I found a Hornby class 156 in very good condition. I invested into Express model's lights and added also interior lights. A chip was found in the drawer, and on we go. 

 

IMG20220929180019 

 

IMG20220929180005 

 

Of course, they are empty, so I need to paint a few sitting figures, also the interior colour is not right. Should be purple and tables creamy grey. But nobody tells me not to open the units again. Probably also to change the chip (is currently a Zimo 623) into something better. 

 

More to come. 

[jpendle]

2 hours ago, Vecchio said:

Probably also to change the chip (is currently a Zimo 623) into something better. 

Better than Zimo? What do you have in mind?

 

John P

[Vecchio]

Well the 623 is not a sound chip, but a small, 0.8A loco decoder. Question is - if we are at a show do we hear the sound? If there is a proper sound file for Zimo I would go for a MX648, but there is also enough space for the larger MX645 (or MS...).

The other contenders for a future layout are a class 37 (on pre-order, with sound) and a black five (already there, with ESU sound, but needs a mechanical overhaul as it wobbles on the last axle). And last but not least - we have to turn the penny these days before we spend it.... 🙂 Probably the wrong emoji - should better use this one 😭 

[5BarVT]

On 27/09/2022 at 10:38, Vecchio said:

This is the complete control building which is responsible for both road and rail bridge. 

DSC_0171 

 

And finally the Banavie signal box. It is just a few yards from the bridge, at the end of Banavie station platform.

DSC_0147

Hi Vecchio,

Are you sure the ‘control building’ is responsible for both bridges?

As far as I recall, back in 1993 the rail bridge was controlled just by Banavie RETB signalbox and I’m not aware of it having changed.  (I have photos somewhere but from a pre digital age and not scanned yet.) 

Not that it matters as far as modelling is concerned!

Paul.

[Vecchio]

Paul, I was reading it somewhere, otherwise I wouldn't have said it. But, if we look at the source of 2022 wisdom (google) we find in Wikipedia:

 

"The bridge is an asymmetric bow truss, with more reinforcement at the end where it is held.

Its operation is fully automated and is controlled by Network Rail staff in the signal box located only a few yards away."

 

Which confirms what you said. I do not think I will have the road bridge on my layout other than represented by either a drawing or photo, so the little black control building will not be there. I am also not sure if I will find space for the signal box, considering that the bridge is 454mm long. We will see, it is still a bit early for this decision. 

[zr2498]

As this is a working bridge and you are modelling in it's current form (I assume), you may be able to get drawings which together with photos would be a great help.

 

Dave

[Vecchio]

Some useful stuff arrived over Christmas, but unfortunately no peep from the bridge kit I ordered from the US.

 

IMG20221226162654 

 

IMG20221226215920 

 

IMG20221226220601 

[Vecchio]

So what's the progress? I got my bridge kit with very useful parts, I think postage, VAT and handling fees were more expensive than the kit itself... 

 

I just started with one of the bridge sides, it is rather difficult as I struggle with cutting and sanding of parts, several I had to make a second or even a third time. Also glue stains are a problem.

Hats off to zr2498, I couldn't see many stains on his work.

 

This is the work on the first bridge side - progress after 2 days (well, I cannot sit 8 hours at this as there are is always family business which has to be done).

 

IMG20230108220519

 

The side is far from being finished, there is a second layer of the diagonal strips to apply before the second halves of the top and bottom girder can be glued on. 

Anyway. Rome wasn't built in a day, I will have some fun in the making....

 

 

 

 

 

 

 

 

 

[Vecchio]

Now the side is almost finished, but I am not totally happy with it - it is a bit too wide - so I re-start with thinner material. (No fear, I keep what I have made so far, who knows if it works with 1mm thick sides...) 

 

IMG20230111162821

 

IMG20230111162839 

 

By the way - the bridge is straight - but the top of my freezer isn't...

[Vecchio]

Slow progress, but finally both new sides are ready. 

I hope I can put them together tomorrow. 

 

Only excuse for slow progress I have is that I am one stone lighter now - well one kidney stone (surgery last week)...

 

IMG20230118195721

[Vecchio]

Today was a rather quiet day so I could put some effort into my bridge. Finally it starts looking like a bridge... 

 

Assembly of the two halves

 

IMG20230119122922 

 

 

Now both halves connected.

 

IMG20230119162549 

 

 

And everything looks better wit a bit of primer. I am far from being ready, but the next design elements will cover up some areas so I decided to paint it now. 

 

IMG20230119172147

 

IMG20230119172214 

 

IMG20230119172234 

 

 

As it is a swing bridge we need a counterweight. So I left the ends (where I suppose also the original has the counterweight sitting) open. What is heavy? Lead. Probably not a sexy material these days but I was working with this material for years as I had to test dimensions (cable industry), and surprise, I am still there without a lead poisoning. What is poisonous is the oxide, not the metal itself. And of course hand washing is a good idea... 

 

IMG20230119173547

 

And into its pockets.

 

IMG20230119173612 

 

 

 

Edited January 19, 2023 by Vecchio

[zr2498]

42 minutes ago, Vecchio said:

 

IMG20230119173612 

 

 

 

Great progress and really looks the part. All that extra rivet detail makes a difference, presumably cut from the kit you purchased.

 

 

[Vecchio]

Some stuff was from the kit, but I also purchased a rivet sheet from slaters. So what is on top is from the bridge kit, what is on the sides is from Slaters. In any case the most important thing is a good eyesight - everything pretty small... 

 

Next challenge is the turntable. The original runs on 8 flanged wheels, I have some 009 wheels spare - so we will see.... 

 

Edited January 19, 2023 by Vecchio
spelling

[lezz01]

It looks very nice. Is it balanced correctly in the right place? I assume that it's going to swing and not be a static model. If it's going to move then you need to make sure that it's correctly balanced or it will give you trouble. You will also need a proper bearing or it will also give you trouble. Something with a tapered roller that will take the load through the axis not at a right angle to the axis will see you right.   

Regards Lez. 

[Vecchio]

Thanks Lez. The lead in the pockets is not enough. But I can add more below the bridge, between the longitudinal girders (not yet fixed to the model). At this point the lead will also be invisible. And yes, I would like to see it turning. For the bearing I use a turntable as it is normally in use at cranes. You have a number of wheels running between 2 plates. The original shows eight wheels as far as I can see from my photos. So I try the same. If it doesn't work with the 009 wheels I use small ball bearings instead. Drawing I made just during the last hour, now I need to find a suitable piece of aluminium. I will pay MK metals a visit tomorrow. 

 

bridge turntable.pdf

Edited January 19, 2023 by Vecchio

[Vecchio]

Now I am making the turntable, which is the "bearing" of the bridge.

 

Material purchased, first I have to cut some handsome discs off.

 

IMG20230120130043 

 

Then I turn a boss on one side, which allows me to hold the workpiece when working on the other side. 

IMG20230120135012 

 

After that the "rail" of my turntable gets turned. 

IMG20230120173911 

 

Many parts have been made, some of them were rather at the small side for an 8 inch machine... 

IMG20230120210754 

 

But unfortunately I made a mistake - the holes I drilled into the hub were quite a bit off-center. Means back in the workshop and another hub to make. 

IMG20230120185301 

 

Assembly only after the weekend. Need to go out and spend some time with my lovely wife who accepts living with a maniac who is producing lots of aluminium swarf...

IMG20230120174329 

 

Edited January 20, 2023 by Vecchio

[Vecchio]

The weekend is ending and I am in my workshop again. Just the hub has to be re-made. 

 

Well, I made one, this time the holes were not off-centre, but the diameter was too small. See below hub no 1 and hub no 2... 

IMG20230122145510

 

On we go with hub no3, now 1.5mm larger in diameter... 

Hub no 3, now at the next stage, the arms are soft soldered in place. 

IMG20230122144541 

 

Now you will see what I planned with the 009 wheels. 

IMG20230122170011 

 

IMG20230122170047 

 

The top part will marry with the bridge, the bottom part will be connected to the foundations. 

IMG20230122170128

 

On this photo you can see (not very well, but you can) the wheels of the original

DSC_0167 

 

A long way to go, but I am happy with the progress so far. 

Edited January 22, 2023 by Vecchio
photo missing.