Bridges of the Sandstone & Termite

A place for discussing garden railway scenery, such as buildings, trees, etc....
User avatar
gregh
Trainee Driver
Trainee Driver
Posts: 566
Joined: Sun Apr 01, 2018 5:44 am
Location: Sydney, Australia
Contact:

Bridges of the Sandstone & Termite

Post by gregh » Fri Nov 02, 2018 3:34 am

My GR needs lots of bridges – which is lucky because I like designing and building them.
So I thought I’d show a few of my creations. Please excuse the photo quality - the old pics are scanned - no digital cameras then.

Episode 1.

When I started building the SaTR, the first problem was to negotiate the big sandstone ledge. This is how it looked before I started:
1-rocks  without bridges C s.jpg
1-rocks without bridges C s.jpg (77.37 KiB) Viewed 8500 times
I finished up needing 4 bridges on this section.
The first was across a small gap between two of the large rocks, which I christened Mint gully for the plant that grows there. As I was in a hurry, my first bridge was a simple couple of bits of wood.
2-bridge1 s.jpg
2-bridge1 s.jpg (79.12 KiB) Viewed 8500 times

Many years later I got around to building a stone arch from Hebel lightweight concrete. It’s only about 40cm long but since it’s on a 1m radius curve I first had to cut the 60x20x20 cm block to fit into the gap, then cut the 1m radius curve, and then cut the arch out. For more info on using Hebel or Thermalite in UK, see my webpage here: http://www.members.optusnet.com.au/satr/hebel.htm
Here’s a train about to enter the ‘cave’. The parapets are cut separately from Hebel (very carefully – it’s fragile stuff when thin) and glued on using silicone.
3-mintgully3 s.jpg
3-mintgully3 s.jpg (81.18 KiB) Viewed 8500 times

Now the track had to turn back on itself, so I decided on a curved timber trestle, made from 25mm x 25mm hardwood tomato stakes. At the time I owned one loco – a Bachmann big hauler and had no idea what minimum radius to use for the curve. I could most easily build the bridge on a 75cm radius so, much to my future regret, that’s what I used. The Big Hauler seemed OK on this radius. (I was building my own track too.) The track is also on a 1:25 grade. I even turned the posts on my lathe to a ‘rough round’ to simulate tree trunks.
Here it is on opening day in 1994.
4-orig trestle and train 8-94 s.jpg
4-orig trestle and train 8-94 s.jpg (70.1 KiB) Viewed 8500 times

As that pic shows, it lead onto a steel arch bridge and then a timber truss. (I’ll return later to the replacement of the trestle on a larger radius.)
The steel arch was made from some leftover steel from an above ground swimming pool, 25x25mm steel angle and 6x3mm flat steel for the hangers. As I pop-rivetted each part I dunked the parts in ‘Kill Rust’ paint so there was a good covering at joints. There has been no rust in over 20 years.
5-panorama rocks (2) Aug94 s.jpg
5-panorama rocks (2) Aug94 s.jpg (81.52 KiB) Viewed 8500 times
The 1m long timber truss is made from 25mm x 25mm tomato stakes. I took the easy way out and made all angles 45 degrees. The vertical tension members are 3mm threaded steel rod so they can be tightened to the correct tension to hold the whole thing together. There’s no glue. I tested it by standing on it before installation. It’s still in service after 24 years.

After 6 years of trying to run longer trains around the 75cm radius curve, up a 1:25 grade, I decided it was time for a deviation. By building a new trestle using posts up to 1.2m long, I could get a 1m radius. I reused the arch and truss bridges but in the process I ‘transposed’ their locations.
These pics shows the before, during and after alignments.
6B-build new trestle(2) 11-2000 s.jpg
6B-build new trestle(2) 11-2000 s.jpg (70.02 KiB) Viewed 8500 times
6-old and new top curves s.jpg
6-old and new top curves s.jpg (155.33 KiB) Viewed 8500 times

This time I used 20mm x 20m tomato stakes so they look more slender.
The old trestle was ‘saved’ by the local Historical Society, but with no funds to maintain it, it is slowly falling apart.
7-build new trestle 11-2000 s.jpg
7-build new trestle 11-2000 s.jpg (78.96 KiB) Viewed 8500 times

This pic illustrates the new arrangement of the truss and steel arch bridges and the curved deviation cut into the rock.
8-new and orig route s.jpg
8-new and orig route s.jpg (206.59 KiB) Viewed 8500 times

This pic shows the long posts I needed to get the 1m radius. Any larger radius would have needed posts down to ground level. It also shows how very difficult it was to layout the new curve ‘in mid air’ on the 1:25 grade, with no level ground underneath for a reference.
9-long bents s.jpg
9-long bents s.jpg (124.79 KiB) Viewed 8500 times

I wanted a ‘fence’ to catch derailments but after much testing I decided I didn’t need a continuous fence but just the posts – if they were close enough together. Much testing using an old 4 wheel wagon pushed at speed to derail convinced me a separation of170 mm would not allow any vehicle to miss posts. They are just visible in the above pic.


This shows that the tree is leaning onto the truss. I have removed the bark on a couple of occasions to give clearance, but ‘soon’ I will have to replace the bridge – maybe just turn it upside down.
10-truss s.jpg
10-truss s.jpg (80.23 KiB) Viewed 8500 times

In the next episode, we’ll move along the line to Melaleuca and the biggest of bridges.
Greg from downunder.
The Sandstone & Termite's website: https://members.optusnet.com.au/satr/satr.htm

User avatar
philipy
Moderator
Moderator
Posts: 5033
Joined: Sun Jan 30, 2011 3:00 pm
Location: South Northants

Re: Bridges of the Sandstone & Termite

Post by philipy » Fri Nov 02, 2018 6:52 am

Thanks Greg. Very impressive structures and I always like these 'how I did...' type posts.

Not only that but you've given me food for thought. I did read your Hebel page a couple of years ago, but I'd forgotten about it. As I've said elesewhere, I have been planning to cast a concrete bridge over my stream when I get that far along, but now I'm wondering if this might be a better bet. I would have the whole winter to carve it and then it would be ready to simply plant next Spring. My major concern is water soaking in and subsequently freezing, so I need to give that some thought.

Edited to add: I've just checked on the Wickes site and it says "Aerated blocks can be used below DPC as infill for Beam and Block flooring systems," so I guess that means that water penetration and low temps shouldn't be an issue.
Philip

User avatar
ge_rik
Administrator
Administrator
Posts: 6497
Joined: Sun Oct 25, 2009 10:20 pm
Location: Cheshire
Contact:

Re: Bridges of the Sandstone & Termite

Post by ge_rik » Fri Nov 02, 2018 7:36 am

Fascinating stuff, Greg. I'm impressed that you tested the timber truss by standing on it. Not sure I would have such confidence in my creations. I've always admired that climb through the sandstone and how you envisaged the route before attacking it with chisel, angle grinder and civil engineering structures.

Rik
------------------------
Peckforton Light Railway - Blog Facebook Youtube

User avatar
tom_tom_go
Driver
Driver
Posts: 4824
Joined: Wed Feb 23, 2011 3:08 am
Location: Kent, UK
Contact:

Re: Bridges of the Sandstone & Termite

Post by tom_tom_go » Fri Nov 02, 2018 7:46 am

I have always wondered why you have two trestle bridges next too each other in your videos and now I know why.

Keep the instalments coming!

User avatar
Andrew
Moderator
Moderator
Posts: 3247
Joined: Tue Jul 03, 2012 1:33 pm
Location: Bristol, UK
Contact:

Re: Bridges of the Sandstone & Termite

Post by Andrew » Sun Nov 04, 2018 8:23 pm

I really enjoyed that, thank you. I love how the bridges all serve a real purpose created by the contours of your garden...

Cheers,

Andrew.

User avatar
gregh
Trainee Driver
Trainee Driver
Posts: 566
Joined: Sun Apr 01, 2018 5:44 am
Location: Sydney, Australia
Contact:

Re: Bridges of the Sandstone & Termite

Post by gregh » Sun Nov 04, 2018 9:46 pm

Thanks for the comments guys. Episode two is being prepared.
Greg from downunder.
The Sandstone & Termite's website: https://members.optusnet.com.au/satr/satr.htm

User avatar
FWLR
Driver
Driver
Posts: 4262
Joined: Sat Aug 05, 2017 9:45 am
Location: Preston, Lancashire, UK

Re: Bridges of the Sandstone & Termite

Post by FWLR » Mon Nov 05, 2018 8:22 am

Greg, I love the bridges, especially the Trestles…You are a brilliant builder… The bridge by the tree would look great upside down.

Have you ever thought of running a stream to something down those rocks Greg. It’s seem’s to be crying out for some water running over them.

Ps. The arched bridge is also brilliant…..

SpudUk
Fireman
Fireman
Posts: 329
Joined: Thu Feb 27, 2014 4:25 pm
Location: Bridgend

Re: Bridges of the Sandstone & Termite

Post by SpudUk » Mon Nov 05, 2018 9:47 am

Love the track bed carved into the rock, and the bridges nestling the gaps. Very atmospheric!
Chris Auckland

User avatar
Lonsdaler
Driver
Driver
Posts: 1226
Joined: Tue May 20, 2014 9:50 am
Location: North Yorkshire

Re: Bridges of the Sandstone & Termite

Post by Lonsdaler » Mon Nov 05, 2018 9:53 am

Very atmospheric stuff. Isn't there a real railway somewhere with an abandoned trestle next to the working one? Arizona or California rings a bell :scratch:
Phil

Sporadic Garden Railer who's inconsistencies know no bounds

My Line - https://gardenrails.org/forum/viewtopic ... 41&t=11077

User avatar
gregh
Trainee Driver
Trainee Driver
Posts: 566
Joined: Sun Apr 01, 2018 5:44 am
Location: Sydney, Australia
Contact:

Re: Bridges of the Sandstone & Termite

Post by gregh » Tue Nov 06, 2018 1:56 am

FWLR wrote: Mon Nov 05, 2018 8:22 am Greg, I love the bridges, especially the Trestles…You are a brilliant builder… The bridge by the tree would look great upside down.
Have you ever thought of running a stream to something down those rocks Greg. It’s seem’s to be crying out for some water running over them.
Long, long ago, before a garden railway, I had a water feature running down the rocks - the pipes are still there. It was a bit like this.
orig waterfall.jpg
orig waterfall.jpg (156.63 KiB) Viewed 8337 times

But when I started the GR, the pond at the bottom was in the way, so it all had to go. No chance to even build a sump as it's sold rock underfoot too.

Still get plenty of waterfalls when we get heavy rain.
I did have to jack-hammer a new 'river bed' for the rain water to avoid the trestle footings and I cut a new channel and bridge at Sandstone (you'll see it in Episode ??)
Greg from downunder.
The Sandstone & Termite's website: https://members.optusnet.com.au/satr/satr.htm

User avatar
FWLR
Driver
Driver
Posts: 4262
Joined: Sat Aug 05, 2017 9:45 am
Location: Preston, Lancashire, UK

Re: Bridges of the Sandstone & Termite

Post by FWLR » Tue Nov 06, 2018 8:58 am

Thanks Greg.

Can’t wait to see the next episode……

User avatar
gregh
Trainee Driver
Trainee Driver
Posts: 566
Joined: Sun Apr 01, 2018 5:44 am
Location: Sydney, Australia
Contact:

Re: Bridges of the Sandstone & Termite

Post by gregh » Tue Nov 06, 2018 10:58 pm

Time for Episode 2
Melaleuca station is on a raised baseboard 40cm high at one end and 120cm at the other. To get to it needed bridges at both ends.
So after my success with tomato stakes trestles, I used a small one here.
1-orig Mela trestle sept97.jpg
1-orig Mela trestle sept97.jpg (155.61 KiB) Viewed 8274 times
2-image18.jpg
2-image18.jpg (113.81 KiB) Viewed 8274 times

The tomato stakes were driven into the dirt and guess what? They rotted away! So a replacement was required. As in the prototype, part of the trestle was infilled with dirt to make an embankment and a steel girder constructed.
Actually this is still the same tomato stake stringers, but covered with a styrene ‘girder’ 1m long. It has not proved as successful as I hoped as it is too fragile and is damaged by possums (and clumsy feet stepping over it !) When and if I replace it, it will be solid timber inside covered by the styrene girder.
3- mela new bridge.JPG
3- mela new bridge.JPG (84.3 KiB) Viewed 8274 times

The old stringers under the styrene.
4-IMG_8411.JPG
4-IMG_8411.JPG (158.78 KiB) Viewed 8274 times

At the other end of Melaleuca baseboard the track is 1.2m above ground and I needed to reverse direction and get down to ground level. This would require what I call the horseshoe curve and as I needed access to the inside, I decided to start with another timber truss that I could ‘duck under’ followed by the big timber trestle on the curve.
The truss is similar to the first one, but used the smaller 20mm square tomato stakes. These proved less durable than the larger ones and are rotting (after 20 years!). It is one panel longer than the other truss at 1.2m, but uses the same 3mm threaded steel rod for tensioning.
1- melatruss.JPG
1- melatruss.JPG (210.54 KiB) Viewed 8274 times

Rotting of the horizontal parts is becoming a problem as you can see here.
2-mela truss composite.jpg
2-mela truss composite.jpg (149.6 KiB) Viewed 8274 times

The big Horseshoe trestle.

Because I now needed a curve, it was back to timber trestle type for the biggest bridge on the line – 7.8m long. This time I had space for a 1.8m radius and needed a 1:40 grade to ‘head for the ‘ground’.
1-horshoe11.jpg
1-horshoe11.jpg (381.62 KiB) Viewed 8274 times
1-horshoe11.jpg
1-horshoe11.jpg (381.62 KiB) Viewed 8274 times

I stuck with the tomato stakes trestle, pounded into the ground method. Big mistake again – but it was quick, if quite complicated to pound them at at the required angle to form the bents. I marked out the centre line of the bridge on the ground, just using a centre peg and string. I started by pounding the centre, vertical post in to the correct height, then on the ground, measured out from it the distance to each of the sloped posts. And pounded them at the angle to give the required separation at the top.
There are 17 bents ( =51 posts), about 45cm apart. Along with the top plates and stringers, I must have used around seventy, 1.8m stakes – the nursery man must have thought I was going to grow LOTS of tomatoes. The cross bracing is the same 8mm thick treated pine I use for sleepers. The bents were pretty wobbly till I added the top stringers and the track – then it’s solid as rock. I did not paint or treat the timber in any way.


This gives a view of most of the bridge.
2-IMG_8266.JPG
2-IMG_8266.JPG (355.8 KiB) Viewed 8274 times

Within 10 years most of the stakes had rotted off at ground level, so I started pouring concrete foundations around them. Using a bolt together formwork and quickset concrete I was able to do 8 in a day. (10+ years on now the posts are rotting inside the concrete, so maybe I’ll have to increase the foundation height. Given enough time they will be concrete piers to the top :-) )
3-new footing.JPG
3-new footing.JPG (207.51 KiB) Viewed 8274 times

In addition, the horizontal bearers and stringers had started to rot so some of them needed replacing so a major refurb was done in 2013. Here’s an example of the ‘rot’.
4-bent No4.JPG
4-bent No4.JPG (245.98 KiB) Viewed 8274 times

work in progress
5-in progress1.JPG
5-in progress1.JPG (211.11 KiB) Viewed 8274 times

Load testing of the finished work. I added some horizontal bracing halfway up the posts. And I painted all the horizontal surfaces of the bearers and stringers.
6-best1.JPG
6-best1.JPG (65.15 KiB) Viewed 8274 times

I wanted ‘fences’ to catch any derailments, so I got my mates to bring their longest wagons and locos around and I marked the max overhang, so I could make sure the fence was far enough from the track. 10x3mm aluminium bar (my old rails) were used for ‘outriggers’ to get the fence far enough out for clearance.
The completed work with new access walkway and fence. The fence is just 75mm nails and fishing line, with some styrene spacers.
7- IMG_8415.JPG
7- IMG_8415.JPG (181.48 KiB) Viewed 8274 times

This video taken from a drone shows a good overall view of the trestle.
https://youtu.be/ek2h161KuRg?t=150
Greg from downunder.
The Sandstone & Termite's website: https://members.optusnet.com.au/satr/satr.htm

User avatar
philipy
Moderator
Moderator
Posts: 5033
Joined: Sun Jan 30, 2011 3:00 pm
Location: South Northants

Re: Bridges of the Sandstone & Termite

Post by philipy » Wed Nov 07, 2018 6:35 am

That big trestle is soooo impressive Greg. I can understand why you didn't paint it but I am surprised that you didn't use creosote or similar preservative on it?
Philip

User avatar
ge_rik
Administrator
Administrator
Posts: 6497
Joined: Sun Oct 25, 2009 10:20 pm
Location: Cheshire
Contact:

Re: Bridges of the Sandstone & Termite

Post by ge_rik » Wed Nov 07, 2018 8:19 am

It's amazing that your wooden bridges have lasted so long without preservatives of any kind. I used to think that your part of Oz was fairly arid until you recommended a video to me showing the development of the Sydney sewage system which has to cope with more annual rainfall than London. :shock:

Rik
------------------------
Peckforton Light Railway - Blog Facebook Youtube

User avatar
FWLR
Driver
Driver
Posts: 4262
Joined: Sat Aug 05, 2017 9:45 am
Location: Preston, Lancashire, UK

Re: Bridges of the Sandstone & Termite

Post by FWLR » Wed Nov 07, 2018 9:00 am

I love your Trestles Greg. Your line is the most impressive I have seen. It makes you think you are actually there, watching the train go through the rocks is amazing…Throughly enjoyable episode.

Just a thought though. :idea: Your Trestles are only just needing repair after 10 or 20 plus years.
To scale that would be about 100 to 120 years wouldn’t it…. :thumbright: :thumbright:

User avatar
IanC
Trainee Driver
Trainee Driver
Posts: 798
Joined: Mon Feb 15, 2016 9:15 am
Location: Nr. Warrington, Cheshire

Re: Bridges of the Sandstone & Termite

Post by IanC » Wed Nov 07, 2018 10:22 am

FWLR wrote: Wed Nov 07, 2018 9:00 am I love your Trestles Greg. Your line is the most impressive I have seen. It makes you think you are actually there, watching the train go through the rocks is amazing…Throughly enjoyable episode.

Just a thought though. :idea: Your Trestles are only just needing repair after 10 or 20 plus years.
To scale that would be about 100 to 120 years wouldn’t it…. :thumbright: :thumbright:
Scale time? That's an interesting concept Rod.
Ian

User avatar
FWLR
Driver
Driver
Posts: 4262
Joined: Sat Aug 05, 2017 9:45 am
Location: Preston, Lancashire, UK

Re: Bridges of the Sandstone & Termite

Post by FWLR » Thu Nov 08, 2018 8:27 am

Infinity and beyond…… :lol: :lol: :lol:

User avatar
gregh
Trainee Driver
Trainee Driver
Posts: 566
Joined: Sun Apr 01, 2018 5:44 am
Location: Sydney, Australia
Contact:

Re: Bridges of the Sandstone & Termite

Post by gregh » Thu Nov 08, 2018 8:51 am

philipy wrote: Wed Nov 07, 2018 6:35 am That big trestle is soooo impressive Greg. I can understand why you didn't paint it but I am surprised that you didn't use creosote or similar preservative on it?
I think I did 'dip' the ends in creosote - probably should have soaked them more. Can't use creosote now.
ge_rik wrote: Wed Nov 07, 2018 8:19 am It's amazing that your wooden bridges have lasted so long without preservatives of any kind. I used to think that your part of Oz was fairly arid until you recommended a video to me showing the development of the Sydney sewage system which has to cope with more annual rainfall than London. :shock:
Rik
We do get lots of rain sometimes. The runoff from 2 neighbours' yards finishes up running under the trestle...
storm trestle.png
storm trestle.png (191.44 KiB) Viewed 7654 times
Greg from downunder.
The Sandstone & Termite's website: https://members.optusnet.com.au/satr/satr.htm

User avatar
gregh
Trainee Driver
Trainee Driver
Posts: 566
Joined: Sun Apr 01, 2018 5:44 am
Location: Sydney, Australia
Contact:

Re: Bridges of the Sandstone & Termite

Post by gregh » Thu Nov 08, 2018 9:00 am

Thanks for everyone's comments.
Just a couple of more pics to 'finish off' the trestle story.

Here's me beside the trestle 21 years apart. The shirt and my hair seem to have 'selectively' faded in the latest pic.
20yearson.JPG
20yearson.JPG (121.04 KiB) Viewed 7652 times


Kookaburras find it a useful lookout place for finding worms.
kooka.JPG
kooka.JPG (262.65 KiB) Viewed 7652 times
Greg from downunder.
The Sandstone & Termite's website: https://members.optusnet.com.au/satr/satr.htm

User avatar
ge_rik
Administrator
Administrator
Posts: 6497
Joined: Sun Oct 25, 2009 10:20 pm
Location: Cheshire
Contact:

Re: Bridges of the Sandstone & Termite

Post by ge_rik » Thu Nov 08, 2018 6:17 pm

Things clearly improve with age, Greg. ;)

Rik
------------------------
Peckforton Light Railway - Blog Facebook Youtube

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests