7mm Pencarrow - Cornish BR(S)
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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.