Chubber Posted May 2, 2015 Share Posted May 2, 2015 I have spent a little time lately watching Yootoobe railway modelling subjects and wondering why so many coal trains, expecially PO wagons (my eyes are drawn to them in particular) are filled to the brim, even heaped high in the middle of the wagon. I would like to know justhow much ended up as 'black ballast'? Other than coke, wouldn't such largess inloading result in over weight stock? Thinking on ballast and stone in Engineering trains, scarecely 2 planks high, tell me I'm wrong. Doug Link to post Share on other sites More sharing options...
hmrspaul Posted May 2, 2015 Share Posted May 2, 2015 Density of the various loads varied considerably, ballast and wet slag were very heavy compared to coal. Some of the last 16ton minerals that I saw loaded with coal were unusually full, I have several such as http://PaulBartlett.zenfolio.com/mineralmortonmxv/e6475e7f Paul Link to post Share on other sites More sharing options...
MarkSG Posted May 2, 2015 Share Posted May 2, 2015 Stone is about twice as heavy[1] as coal, so you can get a far larger volume of coal in a wagon before it's overloaded. I presume that the wagons were filled to the brim because the actual losses in transit were relatively low. [1] To be more precise, stone is nearly twice as dense as coal. Link to post Share on other sites More sharing options...
RMweb Premium Andy Hayter Posted May 2, 2015 RMweb Premium Share Posted May 2, 2015 Also to be considered as well as the density of coal versus stone, is the packing density. To make clear, the density is the weight per volume of a piece of the material. The packing density is the weight of a collection of pieces of the material per volume and the density as measured will be less than the true density because of the air spaces in between. Bricks, stacked neatly side by side and on top of one another, will have packing density almost the same as solid brick, but bricks dropped randomly out of a dumper truck have a much lower packing density (they take up more space for the same number of bricks). Generally the bigger the pieces, the lower will be the packing density if there is ransom stacking - so large lumped coal has a much lower packing density than nugget sized ballast stone. So not only do we have the effect of differences in absolute density we also have differences due to packing density and the different size of the materials being carried. Link to post Share on other sites More sharing options...
black and decker boy Posted May 2, 2015 Share Posted May 2, 2015 Also to be considered as well as the density of coal versus stone, is the packing density. To make clear, the density is the weight per volume of a piece of the material. The packing density is the weight of a collection of pieces of the material per volume and the density as measured will be less than the true density because of the air spaces in between. Bricks, stacked neatly side by side and on top of one another, will have packing density almost the same as solid brick, but bricks dropped randomly out of a dumper truck have a much lower packing density (they take up more space for the same number of bricks). Generally the bigger the pieces, the lower will be the packing density if there is ransom stacking - so large lumped coal has a much lower packing density than nugget sized ballast stone. So not only do we have the effect of differences in absolute density we also have differences due to packing density and the different size of the materials being carried. That only affects the volume the load will take as the wagons will generally be loaded by tonnage (hence weigh bridges at collieries and quarries). 1T of loose coal weighs the same as 1T of solid coal, it just takes up a bit more volume. The volume taken up will alter over the journey as the load will consolidate from vibrations. In modern wagons, the capacity / physical size of the wagon is made to match the intended load.nthe national power bogie hoppers for limestone are much shorter than the matching rakes intended for coal and the new biomass wagons are longer and a totally different design philosophy to cater for the very low density of biomass pellets. Link to post Share on other sites More sharing options...
Arthur Posted May 2, 2015 Share Posted May 2, 2015 Andy's point about packing density is still an important consideration in wagon loading and it's subsequent appearance. Matching weight capacity to volume, as in your National Power example, is all very well if the wagons are in a dedicated service and always carry the same material. Wagons in general service will carry different bulk materials whose density and packing density vary, so, when loaded to maximum weight, the wagon may appear only half full, full, heaped or even be heaped and actually underweight if loaded with, say, coke. Iron ore is a good example. Not only do the ores vary in weight, if excavated in big lumps, it'll have a low packing density, processed or beneficated ores will not only be heavy because of their high iron content, they are of a crushed or pelleted nature which packs together very densely. Link to post Share on other sites More sharing options...
Spitfire2865 Posted May 2, 2015 Share Posted May 2, 2015 I feel the original question was why models of simple 4 wheel opens often show heaps of coal a foot or so over the top of the sides. Then it just spiraled into density vs weight and how modern stock is designed. To go back to the OPs question, I see heaps, but not overflowing. Definitely has enough room to be smoothed flat and still not overflow. Just how stuff falls. Tall in the middle with sloping sides. Link to post Share on other sites More sharing options...
Arthur Posted May 2, 2015 Share Posted May 2, 2015 The OPs question can only be answered by understanding the factors which determine real wagon loading, it's all about density and weight so I fail to see how it's spiralled. Doug mentions coal, stone and ballast and we've been discussing why those loads look different. Understand those factors and you can produce realistic model loading for any material. Or know when you see a poorly modelled load. Link to post Share on other sites More sharing options...
RMweb Premium Andy Hayter Posted May 3, 2015 RMweb Premium Share Posted May 3, 2015 That only affects the volume the load will take as the wagons will generally be loaded by tonnage (hence weigh bridges at collieries and quarries). 1T of loose coal weighs the same as 1T of solid coal, it just takes up a bit more volume. The volume taken up will alter over the journey as the load will consolidate from vibrations. Absolutely correct, and that is why a coal wagon was a seven or eight plank open and a ballast wagon might only be a two plank one. The simple difference in density between ballast stone and coal would suggest that ballast would require a wagon half the height of a coal wagon, but the packing density differences mean that the ballast wagon is smaller than the simple density difference might suggest. This was one of the points questioned by the OP and I think we have explained it. Link to post Share on other sites More sharing options...
Rivercider Posted May 3, 2015 Share Posted May 3, 2015 The difference between the relative density of coal and stone/ballast can be illustrated by the 16t minerals which were transferred to the civil engineers department in the 1980s. Very quickly there were problems of overloading due to the greater density of the spent ballast, the solution was to cut rectangular holes in the sides to prevent overloading, https://www.flickr.com/photos/tutenkhamunsleeping/5434671212/in/photolist-9hf7pN-pEzsVW-bAD993-jgWQJq-ay2cwr-kNzyLH-dvpZPF-9hbXZZ-oWXjTN-d1TuRA-oVH5Ts-bZzp2b-bZBhoj-m38QBC-dBoXYC-pExQUr-dBiwxB-hSkbDq-cZx4Uw-oH6JAu-9x1gLm-dgWUsN-oBRsjU-ddqEn8-4rwLBc-aoEexh-dgWTNn-bah48X-p67hYE-e3hipC-dgWTCM-dgWTC9-dgWTWG-dgWTMC-dgWT2D-dgWSGw-fFiFNK-dgWSLx-knGbtn-9PWFXZ-dgWSRW-dgWSCz-dgWRSX-b95pr6-dgWS3e-dgWSUi-b97FNg-b9HUw2-b97Fw4-b97Eyi cheers Link to post Share on other sites More sharing options...
jonny777 Posted May 3, 2015 Share Posted May 3, 2015 When I watched the High Dyke - Frodingham iron ore trains, from the back garden, there were occasional 16t coal wagons in amongst the 27t tipplers. I often wonder how they managed to get in there, and how long the springs lasted after ~27 tons of ore was dropped onto them. Link to post Share on other sites More sharing options...
Arthur Posted May 3, 2015 Share Posted May 3, 2015 The point is that they shouldn't have had 27 tons if ore in them, they should have been loaded to their rated weight. Photographs of such wagons carrying ore and looking almost empty, despite carrying their maximum rated load, have been commented on before. That's not to say that they were never overloaded though I would imagine BR inspectors would have been vigilant enough. Link to post Share on other sites More sharing options...
RMweb Gold teaky Posted May 3, 2015 RMweb Gold Share Posted May 3, 2015 Would the ore have been loaded in one go or two? I've seen pictures of larger wagons with two mounds of minerals in them. If this also applied to the ore trains then perhaps the 16 tonners only got one 'pile' instead of two? Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted May 3, 2015 RMweb Premium Share Posted May 3, 2015 Would the ore have been loaded in one go or two? I've seen pictures of larger wagons with two mounds of minerals in them. If this also applied to the ore trains then perhaps the 16 tonners only got one 'pile' instead of two? My guess is that it would depend on the type of loading facility. A conveyor belt would be different to a scoop from an excavator, for example. I remember reading an article somewhere, where someone claimed he could tell where MGR coal hoppers were loaded, by the shape & number of humps. Link to post Share on other sites More sharing options...
Arthur Posted May 3, 2015 Share Posted May 3, 2015 Depends on the ore and the loading facility. That loaded direct by face shovel at the ore pit would be three or four bite sized chunks or slabs. Much home, UK ore, was delivered that way. Imported ores, and some domestic ores, were pre treated to remove some of the waste and reduce transport costs prior to shipping. Such ores were dry, and crushed or pelletised, and flowed freely.They would be loaded by grab crane, special ore cranes (Cargo Fleet and Bidston dock) or overhead bunker (Tyne Dock). The loading method would determine the number of 'humps'. Link to post Share on other sites More sharing options...
Rivercider Posted May 3, 2015 Share Posted May 3, 2015 I feel the original question was why models of simple 4 wheel opens often show heaps of coal a foot or so over the top of the sides. Then it just spiraled into density vs weight and how modern stock is designed. To go back to the OPs question, image.jpg I see heaps, but not overflowing. Definitely has enough room to be smoothed flat and still not overflow. Just how stuff falls. Tall in the middle with sloping sides. I think this yard full of export coal is either at or near a docks awaiting shipment? That being the case after loading the wagons will have been shunted at least once or twice then travelled on an unfitted train for ten or twenty miles before being shunted again. If the wagons had been loaded to the top of the sides then any spillage would have taken place in the colliery or nearby yard and the coal would have settled in transit a bit by the time this photo was taken, cheers Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted May 3, 2015 RMweb Gold Share Posted May 3, 2015 When I watched the High Dyke - Frodingham iron ore trains, from the back garden, there were occasional 16t coal wagons in amongst the 27t tipplers. I often wonder how they managed to get in there, and how long the springs lasted after ~27 tons of ore was dropped onto them. Overloading and uneven loading (usually a result of using bucket loaders) was a problem in the early days of the West of England stone trains using ex iron ore tipplers and even some 16 tonners. Outsiders, especially inexperienced outsiders tend to see a railway wagon as a box to fill with whatever they are loading - so they fill it. The result is hot boxes, other damage, and derailments - the latter sometimes being quite serious and/or spectacular. Specialised loading equipment using overhead conveyors normally loads on the centreline and a skilled operator can ensure fairly even distribution along the length of the wagon while the machine itself - if correctly set for the wagon(s) being loaded - prevents overloading. Similarly most collieries loaded coal at screens which put the load mainly on/near the centreline and skilled men would sure sensible distribution along the length of the wagon that sort of loading is reflected in the wagons waiting shipment order in the Cardiff (I'm pretty sure it's Cardiff) picture in post No.7. The load is heaped in the middle of the wagon because that is where it was loaded, it spread from there as more coal was tipped in but usually remained higher in the centre. The picture of course comes from the era when colliers were not paid for small coal hence you don't see any really small stuff - that went on the mine's tip. Link to post Share on other sites More sharing options...
br2975 Posted May 3, 2015 Share Posted May 3, 2015 I think this yard full of export coal is either at or near a docks awaiting shipment? It is - Cardiff Marshalling Sidings - basically alongside the rainforest c*m jungle that is now known as Tidal Sidings. . Brian R Link to post Share on other sites More sharing options...
RMweb Premium corneliuslundie Posted May 3, 2015 RMweb Premium Share Posted May 3, 2015 And since they were paid by the ton collieries would weigh each wagon and ensure they were not giving any away. Link to post Share on other sites More sharing options...
ZiderHead Posted May 3, 2015 Share Posted May 3, 2015 For reference, here is a list of some common bulk materials and how much they would weigh if a 16t minerals wagon were fully loaded with them (e. level to the top): 24t Bauxite, crushed28t Cement - clinker34t Clay, wet excavated20t Coal, Anthracite, broken15t Coal, Bituminous, broken12t Coke44t Concrete, Gravel44t Concrete, Limestone with Portland48t Copper ore26t Earth, moist, excavated29t Earth, wet, excavated32t Earth, soft loose mud26t Flint - silica139t Galena ( lead ore )30t Granite, broken35t Gravel, with sand, natural31t Gravel, dry 1/4 to 2 inch37t Gravel, wet 1/4 to 2 inch53t Iron ore - crushed28t Lime, stone, lump26t Limestone, pulverized29t Marble, broken35t Mud, packed30t Sand with Gravel, dry37t Sand with Gravel, wet29t Shale, broken22t Slag, crushed, 1/4 inch25t Slate, pulverized29t Stone, crushed10t Wood chips - dry edit: this is just a selection of the 340ish materials I have on a spreadsheet, I'm guessing the density of Alfalfa, ground won't be relevant to many modellers, and I haven't even heard of a lot of the stuff. Wool surprised me though - 24t! Link to post Share on other sites More sharing options...
RMweb Premium Andy Hayter Posted May 3, 2015 RMweb Premium Share Posted May 3, 2015 Wool is light(ish) fluffy stuff and transporting it, as is, would be a bit like transporting expanded polystyrene. Since transportation costs are based more per wagonload than per tonne, the solution for wool (but not for expanded polystyrene) is to compress the wool into compact bales where a lot of the air between the fibres has been squeezed out (effectively increasing the packing density many times over). By doing this you can get very high laden weights that would otherwise not be possible. Link to post Share on other sites More sharing options...
Fat Controller Posted May 3, 2015 Share Posted May 3, 2015 From experience of coal-carrying lines in South Wales and elsewhere, I can say that quite a lot of coal did find its way on to the track, either by falling off the top or, more usually, leaking around doors and other apertures. Sometimes, the railway got the choice of wagon for a job horribly wrong, however. One example I saw was what was meant to be a trial run of anthracite from Onllwyn to Mossend, composed of a selection of odds'n'sods. The MEAs were a reasonable enough choice; the same couldn't be said for the couple of 'Limpets', borrowed from the engineer's fleet, where they'd been modified to carry spoil. I saw them at Margam, by when (after perhaps thirty miles), half the load had trickled away. I wonder how much got to Scotland? Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted May 4, 2015 RMweb Premium Share Posted May 4, 2015 For reference, here is a list of some common bulk materials and how much they would weigh if a 16t minerals wagon were fully loaded with them (e. level to the top): 24t Bauxite, crushed 28t Cement - clinker 34t Clay, wet excavated 20t Coal, Anthracite, broken 15t Coal, Bituminous, broken 12t Coke 44t Concrete, Gravel 44t Concrete, Limestone with Portland 48t Copper ore 26t Earth, moist, excavated 29t Earth, wet, excavated 32t Earth, soft loose mud 26t Flint - silica 139t Galena ( lead ore ) 30t Granite, broken 35t Gravel, with sand, natural 31t Gravel, dry 1/4 to 2 inch 37t Gravel, wet 1/4 to 2 inch 53t Iron ore - crushed 28t Lime, stone, lump 26t Limestone, pulverized 29t Marble, broken 35t Mud, packed 30t Sand with Gravel, dry 37t Sand with Gravel, wet 29t Shale, broken 22t Slag, crushed, 1/4 inch 25t Slate, pulverized 29t Stone, crushed 10t Wood chips - dry edit: this is just a selection of the 340ish materials I have on a spreadsheet, I'm guessing the density of Alfalfa, ground won't be relevant to many modellers, and I haven't even heard of a lot of the stuff. Wool surprised me though - 24t! Very good, some of those loadings wouldn't do the wagons any good at all, even before anyone attempted to move them! I'm surprised at dry wood chips, being more than half the weight of coal. Link to post Share on other sites More sharing options...
w124bob Posted May 4, 2015 Share Posted May 4, 2015 Heading for Rugeley with a train from the Coalville area every HAA was at least a couple of tons over weight(according to the TOPS list). Looking back down the train once on the WC mainline at Litchfield you could rarely see the back of the train on dry days, just a black cloud ! Link to post Share on other sites More sharing options...
RMweb Premium Reorte Posted May 5, 2015 RMweb Premium Share Posted May 5, 2015 And nothing on that list is 16t... Bituminous coal at 15 suggests a bit of room for error and I suppose it getting damp could add up to a fair bit extra. Interesting post about the modern wagons further up, is the size variation due to keeping axle weights acceptable? Link to post Share on other sites More sharing options...
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