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Coal played a key part in the life of our Roundhouse. It was used as fuel for the steam locomotives and was the main item hauled by Barrow Hill locomotives around the country. In fact the rise and fall of the importance of coal in our economy had a direct effect on the operation, and ultimate demise, of the shed.
As we know, steam is produced in a locomotives boiler by heating water. Many fuels may be used including wood, oil and coal. It all depended on the availability of the fuel. In the UK the preferred fuel was coal. We did not have the vast forests of other countries which provided an easily accessible fuel and it was in any case 6 to 10 times more efficient than timber. One pound of coal could turn six pounds of water (0.7 gallons) to steam. Therefore, tender capacity ratios were normally close to 14 tons of coal per 10,000 gallons of water. As can be read elsewhere on this website, oil was considered but proved too costly and the source too remote to make commercial sense. The UK made almost exclusive use of its vast supply of fossil fuel, coal.
Some figures were produced which highlighted how much coal was used per mile. These are from the 1927 trials by the LMS involving a Garratt, an S&DJR 7F, an LNWR 0-8-0 and an LMS 0-8-0 on coal trains over the Toton-Brent route. The coal consumption figures in lb/mile were respectively: 112.6, 80.6, 79.0 and 53.9. Taking load into account the figures in lb/ton.mile were 0.07, 0.078, 0.076 and 0.055.
Source: Bradley and Milton Somerset & Dorset Locomotive History
Interestingly the figured highlighted the problems faced by the bigger locomotives, especially the Garrett. The hunger of the locomotive for fuel meant that the driver sometimes had to assist the fireman in maintaining the steam pressure by feeding the cavernous fire box. Shoveling 112 pounds of coal each and every mile must have been truly backbreaking work.
There were many different grades of coal mined. The hardness and composition of the coal depended obviously on the nature of the original trees and also on the depth the seams were found. In very general terms, the deeper the coal the harder it was and became much preferred by many engine designers. Welsh coal was a soft grade and was favoured by the Great Western Railway due to its location. Their locomotives were well engineered to accept this type of coal. Yorkshire coal was a hard variety and ‘Yorkshire Hards’ were much used by L.N.E.R. for their prestigious trains on the main line between Kings Cross and Edinborough.
The coal from the colliery at Blidworth was especially good for producing steam and was often used to test the steaming capability of locomotives.
Derbyshire coal was of varying qualities, some of which was used for gas production and its by-product of coke etc.
Coal supplies to the engine sheds depended mainly on the class of work the sheds did, the sheds stabling the top passenger expresses got the best coal. Mixed operation sheds had a mixture of good and poor coal. Unfortunately freight sheds like Barrow Hill received the poorest quality coal or coal products which was coal dust or ‘slack’ which was mixed with cement, tar or creosote and pressed into house size briquettes or oval shapes called ‘ovoids’. Some larger sized briquettes were made in South Wales, about the size of a breeze block. These had a crown stamped on them and became known as ‘Cardiff Queens’.
Pictures of ovoids above and a 'Cardiff Queen' below.
A locomotive going on a journey of 100 miles or more needed good quality coal so that the steaming rate did not fall off. Good quality coal burns at very high temperatures and does not produce much ash or form clinker which blocks the air flow through the fire grate, cooling the fire and impairing the production of steam.
Freight workings from Barrow Hill were usually between 30 to 60 miles. Because of the low grade coal used there was often delays when the fire was getting dirty and the locomotive was not steaming well because of a build up of ash and clinker. The fireman would shovel some of the debris out of the firebox with a special clinker shovel that all locomotives carried.
On first getting in to a locomotive, the fireman quickly identified if his day was going to be hard by looking at the quality of the coal in the tender. If he was lucky the engine might have paid a visit to a shed with a mechanical coaling plant which dispensed different quality of coals and an ‘accident’ might mean that good quality coal had found its way into a freight locomotive.
The G.W.R. coaled all of its locomotives by hand from coaling stages like the one at Barrow Hill. This was because the fall from the mechanical tipper could break the soft coal into fragments and dust. The slang for this was ‘Bug dust’.
Smaller sheds like Barrow Hill used bunkers or an elevated coaling stage. The coal men would empty coal trucks into wheeled tubs containing about half a ton each. Tipping them into a locomotive tender or bunker as might be illustrated elsewhere on this website, Generally the smaller locomotives like the 3F and 4F would need about 5 tubs whereas the large Stanier type tenders, maybe working into Barrow Hill with a heavy iron stone train from Wellingbrough, would take about 8 tubs (4 tons) for the 70 mile journey.
Of course, saving money was important and the railway companies would stock pile coal in the summer when prices were low and sheds like Barrow Hill would have had a coal reserve. Unfortunately this would deteriorate after it had been weathered, picked up with a shovel with an accumulation of rubbish like ash and ballast before being shunted onto the coaling stage. It was supposed to be mixed with ‘new’ coal (as were the briquettes and ovoids). A fireman offered a tub of picked up coal would often say “I don’t want that!”. Poor coal was a good excuse for a ‘lost time’ ticket issued to a driver.
Dave Darwin 6/11/2016
Edited and additional research M Creagh