Bull bridge accident
Encyclopedia
The Bull bridge accident was a failure of a cast-iron bridge at Bullbridge
, near Ambergate
in Derbyshire
on 26 September 1860. As a goods train was passing over the bridge at Bullbridge
, the structure failed suddenly, causing the derailment of the majority of the wagons. There were fortunately no casualties, but it was a warning of the fundamental weakness of many of such bridges on the British rail network.
track between Derby
and Chesterfield
, on the night of 26 September 1860. With visibility only about 10 yards due to fog, the train was proceeding northwards at only 14 mph. It was a long train, with 27 wagons loaded with salt, two loaded goods vans, and brake van, hauled by a tender locomotive. The heavy load was causing some slippage of the engine's driving wheels on the rail. Half a mile beyond Ambergate
station, the driver suddenly noticed that the engine's rear wheels were no longer on the rails. He shut off steam, stopped the engine and went to investigate.
His tender was attached to only two wagons, and they were all off the rails too. There were two more wagons about 10 yards behind, close to Bull bridge, a small viaduct
over a local road. The next nine wagons behind were piled in a heap about 25 feet high from the bottom of the road, reaching up to the telegraph wires by the side of the track. The guard in the brake van had been thrown head first against the front panel when the accident occurred, but was not seriously hurt. All the wagons behind the bridge were still on the line.
When examined by the driver and fireman, one of the cast iron girders of the bridge was found to have fractured, unusually near to one of the abutments, rather than at the centre of the beam. The track was supported by a pair of identical girders with Barlow rail
s cut to length laid across the inner flange, with asphalted ballast on top, just below the sleepers. When Captain Henry Whatley Tyler
of the Railway Inspectorate examined the fracture surface, he found it rusted over, but the evidence of those who had seen it first, showed just what had happened. The cast iron
girder had broken vertically from an enormous defect in the web and flanges, where there was a complete gap between the sides. The girder was completely defective here, but why no one had spotted it before the accident remains a mystery. Tyler suggests that it may have grown from an internal void with time, simply because such a defect would surely have been discovered either by the foundry or the builders. The girder had been installed 23 years before, in 1837, and should have supported a central load of 90 tons if in good condition. The pair of girders should have supported a total load of 360 tons distributed over all the structure, and Tyler stated that the girder was much bigger than was needed for the job. The engine weighed 31 tons and the tender 18 tons.
The source of the defect remains unknown, but may have been caused initially by a "cold shut", where the molten metal does not fuse together during metal casting. It often occurs when two waves of fast cooling cast iron meet, but why it should have occurred only about 10 feet from one end remains unknown. It could have grown with repeated loading from passing traffic, and Tyler thought it lucky that it had failed when a goods train was passing, rather than a passenger train, when casualties would have been inevitable. So it is possible that fatigue
had caused the failure by steady growth of a brittle crack from the initial defect.
next year in 1861, there should have been some concern within the railway companies about the number of cast iron girders used as under-bridges on railway lines. Engineers would also have been aware of the problems of cast-iron in railway bridges after the failure of the Dee bridge in 1847. Whether or not such structures were inspected is unknown. Later events seem to negate the possibility, because several more collapses occurred some years later, at the Inverythan crash and the Norwood Junction rail accident
in 1891. Thereafter, all cast-iron underbridges on the rail network were eventually replaced by steel structures.
Bullbridge
Bullbridge is a small village in Derbyshire. The Bull bridge accident happened here in 1860.-The village:Bullbridge has a population of approx...
, near Ambergate
Ambergate
Ambergate is a village in Derbyshire, England, where the River Amber joins the River Derwent.Until the early nineteenth century it was known as Toadmoor, with no more than a few artisans' cottages. The southerly half of the village was still shown as such on the Ordnance Survey's maps.It is about ...
in Derbyshire
Derbyshire
Derbyshire is a county in the East Midlands of England. A substantial portion of the Peak District National Park lies within Derbyshire. The northern part of Derbyshire overlaps with the Pennines, a famous chain of hills and mountains. The county contains within its boundary of approx...
on 26 September 1860. As a goods train was passing over the bridge at Bullbridge
Bullbridge
Bullbridge is a small village in Derbyshire. The Bull bridge accident happened here in 1860.-The village:Bullbridge has a population of approx...
, the structure failed suddenly, causing the derailment of the majority of the wagons. There were fortunately no casualties, but it was a warning of the fundamental weakness of many of such bridges on the British rail network.
The accident
The accident happened on the Midland RailwayMidland Railway
The Midland Railway was a railway company in the United Kingdom from 1844 to 1922, when it became part of the London, Midland and Scottish Railway....
track between Derby
Derby
Derby , is a city and unitary authority in the East Midlands region of England. It lies upon the banks of the River Derwent and is located in the south of the ceremonial county of Derbyshire. In the 2001 census, the population of the city was 233,700, whilst that of the Derby Urban Area was 229,407...
and Chesterfield
Chesterfield
Chesterfield is a market town and a borough of Derbyshire, England. It lies north of Derby, on a confluence of the rivers Rother and Hipper. Its population is 70,260 , making it Derbyshire's largest town...
, on the night of 26 September 1860. With visibility only about 10 yards due to fog, the train was proceeding northwards at only 14 mph. It was a long train, with 27 wagons loaded with salt, two loaded goods vans, and brake van, hauled by a tender locomotive. The heavy load was causing some slippage of the engine's driving wheels on the rail. Half a mile beyond Ambergate
Ambergate
Ambergate is a village in Derbyshire, England, where the River Amber joins the River Derwent.Until the early nineteenth century it was known as Toadmoor, with no more than a few artisans' cottages. The southerly half of the village was still shown as such on the Ordnance Survey's maps.It is about ...
station, the driver suddenly noticed that the engine's rear wheels were no longer on the rails. He shut off steam, stopped the engine and went to investigate.
His tender was attached to only two wagons, and they were all off the rails too. There were two more wagons about 10 yards behind, close to Bull bridge, a small viaduct
Viaduct
A viaduct is a bridge composed of several small spans. The term viaduct is derived from the Latin via for road and ducere to lead something. However, the Ancient Romans did not use that term per se; it is a modern derivation from an analogy with aqueduct. Like the Roman aqueducts, many early...
over a local road. The next nine wagons behind were piled in a heap about 25 feet high from the bottom of the road, reaching up to the telegraph wires by the side of the track. The guard in the brake van had been thrown head first against the front panel when the accident occurred, but was not seriously hurt. All the wagons behind the bridge were still on the line.
Investigation
Barlow rail
Barlow rail was a rolled rail section used on early railways. It has wide flaring feet and was designed to be laid direct on the ballast, without requiring sleepers...
s cut to length laid across the inner flange, with asphalted ballast on top, just below the sleepers. When Captain Henry Whatley Tyler
Henry Whatley Tyler
Sir Henry Whatley Tyler was a British Inspector of Railways, Railway Company director and Conservative politician who sat in the House of Commons from 1880 to 1892.-Early life:...
of the Railway Inspectorate examined the fracture surface, he found it rusted over, but the evidence of those who had seen it first, showed just what had happened. The cast iron
Cast iron
Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...
girder had broken vertically from an enormous defect in the web and flanges, where there was a complete gap between the sides. The girder was completely defective here, but why no one had spotted it before the accident remains a mystery. Tyler suggests that it may have grown from an internal void with time, simply because such a defect would surely have been discovered either by the foundry or the builders. The girder had been installed 23 years before, in 1837, and should have supported a central load of 90 tons if in good condition. The pair of girders should have supported a total load of 360 tons distributed over all the structure, and Tyler stated that the girder was much bigger than was needed for the job. The engine weighed 31 tons and the tender 18 tons.
The source of the defect remains unknown, but may have been caused initially by a "cold shut", where the molten metal does not fuse together during metal casting. It often occurs when two waves of fast cooling cast iron meet, but why it should have occurred only about 10 feet from one end remains unknown. It could have grown with repeated loading from passing traffic, and Tyler thought it lucky that it had failed when a goods train was passing, rather than a passenger train, when casualties would have been inevitable. So it is possible that fatigue
Fatigue (material)
'In materials science, fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. The nominal maximum stress values are less than the ultimate tensile stress limit, and may be below the yield stress limit of the material.Fatigue occurs...
had caused the failure by steady growth of a brittle crack from the initial defect.
Implications
Together with the Wooton bridge collapseWooton bridge collapse
The Wootton bridge collapse occurred on 11 June 1861, when the rail bridge at Wootton collapsed under the weight of a passing goods train on the line between Leamington Spa and Kenilworth owned by the London and North Western Railway Company. The train had passed over the bridge safely in the...
next year in 1861, there should have been some concern within the railway companies about the number of cast iron girders used as under-bridges on railway lines. Engineers would also have been aware of the problems of cast-iron in railway bridges after the failure of the Dee bridge in 1847. Whether or not such structures were inspected is unknown. Later events seem to negate the possibility, because several more collapses occurred some years later, at the Inverythan crash and the Norwood Junction rail accident
Norwood Junction rail accident
The Norwood Junction railway crash occurred on 1 May 1891, when a cast iron under-bridge some 60 yards north east of Norwood Junction railway station fractured under an express train from Brighton to London in southern England....
in 1891. Thereafter, all cast-iron underbridges on the rail network were eventually replaced by steel structures.
See also
- Dee bridge disasterDee bridge disasterThe Dee bridge disaster was a rail accident that occurred on 24 May 1847 in Chester with five fatalities.A new bridge across the River Dee was needed for the Chester and Holyhead Railway, a project planned in the 1840s for the expanding British railway system. It was built using cast iron girders,...
- Inverythan crash
- Norwood Junction rail accidentNorwood Junction rail accidentThe Norwood Junction railway crash occurred on 1 May 1891, when a cast iron under-bridge some 60 yards north east of Norwood Junction railway station fractured under an express train from Brighton to London in southern England....
- Wooton bridge collapseWooton bridge collapseThe Wootton bridge collapse occurred on 11 June 1861, when the rail bridge at Wootton collapsed under the weight of a passing goods train on the line between Leamington Spa and Kenilworth owned by the London and North Western Railway Company. The train had passed over the bridge safely in the...