7mm Pencarrow - Cornish BR(S)
- Thread starter Pencarrow
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Osgood
Western Thunderer
It appears to be normal practice for the spandrel courses (the bits around the arch) to be horizontal and the parapet courses to follow the gradient.
That is from evidence in the excellent Bridges For Modellers book referenced on a recent thread - and there's a great example (2 or 3 down) here:
oaktreesstudio.wordpress.com
That is from evidence in the excellent Bridges For Modellers book referenced on a recent thread - and there's a great example (2 or 3 down) here:
Victorian Railway Bridges in Black and White
Clues to an industrial history criss-cross our now-green-and-peaceful landscape in the form of old railways and waggonways. These old transport tracks now serve as walking and cycling trails by whi…
oaktreesstudio.wordpress.com
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daifly
Western Thunderer
I stand corrected!
Found this one as a nice example with a fairly steep roadway above:
© Copyright James K Muldoon and licensed for reuse under creativecommons.org/licenses/by-sa/2.0
Dave
Found this one as a nice example with a fairly steep roadway above:
© Copyright James K Muldoon and licensed for reuse under creativecommons.org/licenses/by-sa/2.0
Dave
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Osgood
Western Thunderer
Pencarrow
Western Thunderer
Hi both,
Yes it seems normal for the parapet courses to follow the gradient of the road. However, there are quite a few bridges where that's not the case.
The bridge over the Bodmin North branch at Dunmere is one such non-standard example. It was built later than the one at Polbrock when the LSWR straightened out the worst of the tight curves on the line.
Having driven over it twice yesterday, I'm also reminded that a bridge on the eastern side of Tamworth over the Birmingham to Derby line is another example.
I think it's a case of looking at structures in your modelled area to see which approach was used, and then copy it.
The difficulty comes when you go off piste and have to guess what they would have done. In my case that's the later addition of the girder bridge and working out what the interface between the two would look like.
Yes it seems normal for the parapet courses to follow the gradient of the road. However, there are quite a few bridges where that's not the case.
The bridge over the Bodmin North branch at Dunmere is one such non-standard example. It was built later than the one at Polbrock when the LSWR straightened out the worst of the tight curves on the line.
Having driven over it twice yesterday, I'm also reminded that a bridge on the eastern side of Tamworth over the Birmingham to Derby line is another example.
I think it's a case of looking at structures in your modelled area to see which approach was used, and then copy it.
The difficulty comes when you go off piste and have to guess what they would have done. In my case that's the later addition of the girder bridge and working out what the interface between the two would look like.
Pencarrow
Western Thunderer
Indeed!
As with the rolling stock, find your prototype and follow what was done at that time, in that location, by that railway company's contractor.
LarryG
Western Thunderer
On Cambrian and GWR overbridges in North Wales, additional weight above a bridge arch is reduced to an absolute minimum by forming parapets from cast iron railings and even timber. This also applied on road bridges where a steel girder is suspended between two stone pillars.
I marvel at the old stone masons who built bridges to last. In contrast, I was partly-what involved in a bridge over the Abergele byepass (now A55), which for many years now has been reduced to single file traffic!
I marvel at the old stone masons who built bridges to last. In contrast, I was partly-what involved in a bridge over the Abergele byepass (now A55), which for many years now has been reduced to single file traffic!
Yorkshire Dave
Western Thunderer
What they probably didn't foresee was the increase in weight and volume of road traffic which today is shaking old bridges apart by the constant vibration.
Even so, some early (and later) stone bridges had weight restriction signs - this appears to be a common design (and weight restriction) among railway companies Cast Iron Bridge Diamond. MIDLAND RAILWAY COMPANY - Cast Iron Signs
Pencarrow
Western Thunderer
Having done an inspection of the original Firth of Forth suspension bring and having also been under the spaghetti junction structures, it's shocking how much traffic weights, volumes and impacts literally shake bridges to bits. 44T lorries, not 2T electric cars, weren't anticipated when they were designed.
simond
Western Thunderer
Given the parlous state of the comb joints (or whatever pases for them) on the elevated M6 SE of spaghetti junction, I’m amazed it hasn’t rattled to bits years ago. The habitual congestion is not normally a reason to use the toll road on a motorbike, but the gu-dunk-ga-dunk every 30 metres surely is. It’s awful.
Pencarrow
Western Thunderer
In the 30+ years I've been driving over the M6 elevated parts through Brum, I've seen so many new wonder product expansion joints tried out and none seems to last. The metal ones come loose and break. The bituminous ones deform into pits and ski jumps.
At some point the whole thing will have to be replaced but that's not something that's easily achievable.
oldravendale
Western Thunderer
Just do what they do in Kenya.... Build a new road round it. Easy.... You'll probably need to get the Chinese involved, though.
Brian
Need to start a new thread if this is to continue.
Phil O
Western Thunderer
There was one of those on Wimblehurst road in Horsham, over the Dorking to Horsham line. I can't remember what the weight restriction was, but I think it was 2 tons or less.
Pencarrow
Western Thunderer
We refer to it as the naughty Pannier. Or sometimes the £#@& naughty Pannier.
Dog Star
Western Thunderer
As does the interior view of the wagon with wood sheeting and floor. Very tasty.
Rgds, Graham
Osgood
Western Thunderer
Is it possible to use a hot air gun to manipulate sheet material like this stone?
If starting at arch end in this case it would need curving and pulling down at same time, but given relatively low height might be possible.
You probably couldn’t do it in situ given the Plastikard backing structure, but a piece of ply suitably curved might suffice as a curved template.
Practical solution or just hot air?
If starting at arch end in this case it would need curving and pulling down at same time, but given relatively low height might be possible.
You probably couldn’t do it in situ given the Plastikard backing structure, but a piece of ply suitably curved might suffice as a curved template.
Practical solution or just hot air?