Proceedings.] FOX OR THE GREAT CENTRAL RAILWAY EXTENSION. 23 (Paper No. 3209.) ‘I The Great Central Railway Extension : Southern Division.” By FRANCISDOUGLAS Fox, M.A., Assoc. M. Inst. C.E. THE SouthernDivision of thisrailway commences at a point 131miles 44 chains fromManchester, and 51miles 69 chains from thejunction at Annesley, nearNottingham, with the original Manchester, Sheffield and Lincolnshire Railway, which, together with the newmain-line extension to London (Marylebone Station), has been renamed the ‘‘ Great Central Hailway.” The railway runs ina southerly direction through the counties of Warwick, Northampton, Buckingham, and Oxford to a junction at Quainton Road with the Aylesbury and Buckingham branch of the Metropolitan Railway, where the Southern Division of the railway ends at a point 16li miles from Manchester (Fig. 1, Plate 3). Junctions, both up and down, are provided at Woodford, with the East and West Junction Railway, givingaccess to Blis- worthand Stratford-on-Avon. At Moreton-Pinckney,138 miles 50 chains fromManchester, a double line branch, Sk miles in length, runs from the main line in a south-westerly direction to a junction at Banbury with the Great Western Railway’s main London and Birmingham line. Themain line between Rugbyand Q,uainton Road passes through a richgrazing country, not thickly populated,which is generally of a smoothly undulating character, withridges running east and west, consisting of lias and Oxford clays and beds of a softish white limestone. As the direction of the railway is almost due north and south, heavy earthworks were entailed in cutting through the ridges and embanking the valleys. Cut- tings and embankments over 50 feet in depth and height respec- tirely are of frequent occurrence, and in one case, at Catesby, where the ridge was of unusual height, a tunnel 3,000 yards in length was considered necessary. Downloaded by [ University of Sussex] on [16/09/16]. Copyright © ICE Publishing, all rights reserved. 24 FOX ON THE GREAT CENTRALRAILWAY EXTENSION. [Minutes Of The difficulty of crossing suchcountry econonlically was increased by the fact that the maxirnunl gradient allowed on this division was 1 in 176, or 30 feet in a mile, and the minimum curve was 60 chainsradius, and that in one case only, the normal curve being of 1 mile radius. These severe restrictions were due to the Company’s resolve to secure a first-class running line, as direct as possible, and with easy curves and flat gradients, so as to admit of high speeds. The highest point above the sea reached on this division is 503 feet (Fig. 2, Plate 3), at Charwelton Station, and between that station and Brackley the railway follows more or less the line of watershed, crossing t.he Cherwell river which flows west and joins the Thames at Oxford, and the Bedfordshire Ouse which flows east into the Wash. Stationshave beenprovided for passengers and goods as follows :- LISTOF STATIONS. Distance Distance rom Man- betwreu --chester. --Stations. M. c. nc. c. 1. Rugby . Second Warwickshire . 122 60 116 2. Willougdby . Country type .. 127 35 455 3. Charwelton . ,1 ,, Northamptonshire . 134 40 705 4. Woodforcl , . I, ,> ,I I, 136 70 2 30 5. Culworth . 1, ,, ,1 17 139 70 3 00 6. Helmdon . ,, ,. 143 40 350 7. Breckley . S&ond” 9, 1, 146 GO 3 20 6. Calvert . Oxfordsliire. 151 40 4 60 9. Pinmere . ,I Buckinghamshire . 157 20 560 South end of Southern’ Division . 161 40 --4 20 1 Total . 39 76 GENERALDESCRIPTION. Fencing and Gates.-The fencing throughout, except in a few places, where Local Board or private requirements had to be met, was of theordinary post and five-rail Baltic creosoted timber type, standing 4 feet G inches high. Earthwork.-In tipping the embankments no lift was allowed to exceed 20 feet, and as far as possible thetips werecarried on together by end-tip wagons. On account, however, of the unusual magnitude of the earthworks and thelimited time at disposal, the * From commencement of the Southern Division. Downloaded by [ University of Sussex] on [16/09/16]. Copyright © ICE Publishing, all rights reserved. Procec&ngs.] FOX ON THE GREAT CENTRAL RAILWAY EXTENSION. 25 Contractors were allowed in special cases to use side-tip wagons, working across from an end-tip bank at one side until the full width of theembankment was reached. TheAuthor considers the question of end- versus side-tipping one of great interest, on which opinions seem to differ considerably. The heavy cuttings were excavated in liftsof about 16 feet deep by Ruston and Proctor steam-navvies, with gangs of men following close behind in the case of the side cuts, to trim theslopes, the steam-navvies working at night by the aid of the “Lucigen ” light. The total quantity of earthwork excavated on the southern division amounts to some 6,200,000 cubicyards, 90 per cent. of this being stiff lias and Oxford clays. The success andrapidity of the excavation in cuttings was largely due to thesystem of drainage adopted. The width of formation, Figs. 3, Plate 3, is 28 feet clear in cutting, and generally31 feet clear on embankments, but the latter width was often increased to 33 feet, as there wasa preponderance of cutting overembankment. Theleast clear width allowed between piers of bridges, etc., is 26 feet 3 inches. The minimum headway above rails is 14 feet 6 inches. The loading gauge is shown in Fig. 4, Plate 3. ,Concrete.--Owing to the scarcity of good clean gravel, except on the sub-section from Charwelton to Woodford, it was decided to use clean ironstone slag and burnt ballast where stone could not be obtained. The Contractors installed a large sand- and gravel- washingmachine at Woodford whichdid excellent work. Its capacity was about 30 cubic yards of washed gravel per day of 10 hours. Theproportions of concrete used were, in ordinary foundations, 7 to 1 (5 of gravel or broken stone and 2 of sand to 1 of Portland cement); and 5 to 1 (3 of gravel or broken stone and 2 of sand to 1 of blue lias lime). The concrete was brought up in layers not exceeding 2 feet in depthand well punned or trodden. It wasentirely mixed by hand on boards covered with canvas to prevent waste. “ Plums ” or“burrs ” wereallowed to be used wherethe thickness of the concrete exceeded 3 feet. A layer of 1 foot of concrete was deposited, then one of plums of hardnative limestone or Leicester granite placed on theirflat beds, andnot exceeding 12 inches in any direction,with 9-inch spacingsbetween the blocks. Concretemixed ratherwet was then deposited around the plums, andcarefully punned into place untilthe whole became an elastic mass. Plums were only allowed where the load tobe borne was dead weight or applied normally. Mass con- crete was allowed to be tipped into the foundations a barrow- Downloaded by [ University of Sussex] on [16/09/16]. Copyright © ICE Publishing, all rights reserved. 26 FOX ON THE GREAT CENTRAL RAILWAY EXTENSION. [Minutes Of load at a time,where the depth did not exceed 6 feet. Upon the 12-inch layer of plumsand concrete anotherlayer of concrete 12inches thick was deposited, and so on alternately. Only hardclinker-burnt clay ballast was admitted. This was found to make a durable and hard concrete with cement, lime having proved unsuitable for this purpose. Sand of an excellent quality, brought by train from Leighton Buzzard, was very largely used on contracts Nos. 5 and 6. The use of burnt clay ballast in concrete andmortar is, theAuthor thinks, asubject worth discussion. Brickwork.-All brickwork was faced with Staffordshire brindle bricks in black mortarwith an ordinarydrawn weather-joint, which makes an excellent finish, and imparts a less sombre colour tothe structure than the more expensiveStaffordshire blue pressed bricks. Being of rougher grain, the brindle bricks bond better than the highly finished and smoother blue bricks, and are more easily handled and quartered. All copings to viaducts and bridges were built in Staffordshire double bull-nose bluebrick, 14 inches and 18 inches wide. The brickwork was built in old English bond, with two ‘‘ herringbone ” courses crossing each other at about every tenth course, in cement or blue lias lime, as ordered by the Engineers. All arch rings were built of unbonded work, except where the courses corresponded, and there headers were used as bonders. The bulk of the arch-work in viaducts and large arch bridges was built in cement. All brickwork in bridges and culverts below 12 inches above the level of the ground was builtin cement. Allbrickwork in abutments and walls, etc., against which earthwork would lie, was backed up with l5 inches of broken stone dry lining, and the drainage was led by clay- puddle backing andweep-pipes to the front of the wall. Stonework.-Stone, rock-faced, was used only inbedstones, pilaster caps, newel1 caps, and in a few cases in string courses, and was obtained from the Derbyshire gritstone quarries. Economy being of the first importance, very little fancy ashlarwork waspermitted, and for the most part brindle brickwork of substantial character was adopted throughout. TOinsure safety in fast running,level crossings, whether of public roads, accommodation roads or footpaths, have almost entirely been avoided, bridgesbeing provided, roads diverted, or the owners or public authorities compensated and the roads or paths closed. This should insure a great economy of working and the saving of the wages of watchmen, &c. Nextin importance to a comparatively level and direct route, free from obstacles which Downloaded by [ University of Sussex] on [16/09/16]. Copyright © ICE Publishing, all rights reserved. Proceedings.] FOX ON THE GREAT CENTRAL RAILWAY EXTENSION. 27 might limit the speed of trains, was the provision of a first-clam road-bed, and to this end no pains were spared.