Chapter 5

Turning now to the London and North-Western Railway, we find that between 1862 and 1865 the express trains were worked with a handsome type of engines, known as the "Lady of the Lake" class. They have outside cylinders 16 in. diameter and 24 in. stroke, with single driving wheels of 7 ft. 6 in. diameter, and leading and trailing wheels 3 ft. 6 in. diameter, with a total wheel base of 15 ft. 5 in. The frames are single, with inside bearings to all the wheels. The boiler is 11 ft. long and 4 ft. diameter, and the heating surface is in the tubes, 1,013 feet; fire-box, 85 ft.; total, 1,098 feet. The tractive power per lb. of steam pressure in the cylinders is 68 lb. The weight in full working order is on the leading wheels, 9 tons 8 cwt.; driving wheels, 11 tons 10 cwt.; trailing wheels, 6 tons 2 cwt.; total, 27 tons. The tender weighs 17½ tons in working order. These engines burn about 27 lb. of coal per mile with trains of the gross weight of 117 tons, which is not at all an economical duty. About 1872, the weight of the heavier express trains on the North-Western had so increased, that a new standard type for this service was designed, and is now the standard passenger engine; it has inside cylinders 17 in. diameter and 24 in. stroke; the driving and trailing wheels are coupled, and are 6 ft. 6 in. diameter, and the leading wheels 3 ft. 6 in. The frames of steel are single, with inside bearings to all the wheels, and the boiler, of steel, is 9 ft. 10 in. long and 4 ft. 2 in. diameter. The steel used has a tensile strength of 32 to 34 tons per square inch, all the rivets are put in by hydraulic pressure, and the magnetic oxide on the surface of the plates where they overlap is washed off by a little weak sal-ammoniac and water. In testing, steam is first got up to 30 lb. on the square inch, the boiler is then allowed to cool, it is then proved to 200 lb. with hydraulic pressure, and afterward to 160 lb. with steam. The fire-box is of copper, fitted with a fire brick arch for coal burning, and the grate area is 15 square feet. The heating surface is, in the tubes, 1,013 square feet; fire-box, 89 square feet; total, 1,102 square feet. The wheel base is 15 ft. 8 in., and the tractive power 88 lb. for each lb. of steam pressure in the cylinders. These engines, working the fast passenger trains at a speed of about 45 miles per hour, burn about 35 lb. of coal per mile, when taking trains weighing about 230 tons gross. A variation from this type has been adopted on the Northern and Welsh sections, known as the "Precursor" class. These engines have 5 ft. 6 in. coupled wheels, and weigh 31 tons 8 cwt. in working order, but in other respects are very similar to the standard engines just described; with the Scotch express, averaging in total weight 187 tons, between Crewe and Carlisle, over heavy gradients, they burn 33 lb. of coal per mile. These engines, although much more powerful than the standard type, are not nearly of so handsome an appearance, the drivers seeming much too small for the boiler under which they are placed. But by far the boldest innovation on existing practice is the new class of compound locomotives now being introduced by Mr. Webb. It is a six wheel engine, with leading wheels 4 ft. diameter, and two pairs of drivers, 6 ft. 6 in. diameter. The trailing drivers are driven by a pair of outside cylinders, 18 in. diameter and 24 in. stroke; and the leading drivers by a single low-pressure cylinder--which takes the exhaust steam from the high-pressure cylinders--of 26 in. diameter and 24 in. stroke, placed under the center of the smoke-box. The boiler is the same as that in the standard type of engine, but the wheel base is 17 ft. 7 in., and in order to allow it to traverse curves easily, the front axle is fitted with a radial axle-box, which is in one casting from journal to journal, and fitted at each end with brass steps for the bearings; the box is radial, struck from the center of the rigid wheel base, and the horn plates are curved to suit the box, the lateral motion being controlled by strong springs. Another peculiarity of this engine is that, instead of the ordinary link motion, it is fitted with Joy's valve gear, which is now being more and more adopted. This gear--which is of a most ingenious decription--dispenses altogether with eccentrics, and so allows the inside bearings to be much increased, those on these engines being 13½ in. long; and it is also claimed for it that it is simpler and less costly, weighs less, and is more correct in its action than the ordinary link motion; the friction is less, the working parts are simplified, it takes less oil, and is well under the driver's eye. It also allows larger cylinders to be got in between the frames of inside cylinder engines, as, the slide valves may be placed on the top or bottom of the cylinders. This latter advantage is a great one, as, with the ordinary link motion, large cylinders are exceedingly difficult to design so as to get the requisite clear exhaust. The action of the gear is as follows: A rod, a, is fixed by a pin at b, on which it is free to turn, and is attached to a rod, c, at d, the other end of which link is fastened to the connecting rod at e. At the point, f, in this rod another lever, g, is connected to it, the upper end of which is coupled to the valve rod, h, at i, and just below this point a second connection is made to a block at j, sliding in a short curved piece, k. The inclination of the block, k, governs the travel of the valve. The total weight of the engine in working order is: On the leading wheels, 10 tons 8 cwt.; front drivers, 14 tons 4 cwt.; rear drivers, 13 tons 10 cwt.; total, 37.75 tons. The tender weighs 25 tons in full working order. The boiler pressure is 150 lb., and the usual point of cut-off in the high pressure cylinders, when running at speed, is half-stroke, while the pressure of steam admitted to the large cylinder is never to exceed 75 lb. per square inch. The average consumption of coal between London and Crewe is 26.6 lb. per train mile, or about 8 lb. per mile less than the standard coupled engine. In an experiment made in October, 1883, one of these engines took the Scotch express from Euston to Carlisle at an average speed, between stations, of 44 miles an hour, the engine, tender, and train weighing 230 tons, with a consumption of 29½ lb. of coal per mile, and an evaporation of 8.5 lb. of water per pound of fuel.

Mr. Webb's object, in designing this engine was to secure in the first place a greater economy of fuel, and secondly, to do away with coupling rods, while at the same time obtaining greater adhesion, with the freedom of a single engine. The cost is much more than an ordinary locomotive, but the saving in fuel is said to be 20 per cent. over the other engines of the North Western Rail way. These engines run very sweetly, and are said to steam freely, although with only half the usual number of blasts; but from the small size of the high pressure cylinders, they are liable to slip when starting heavy trains, as the low pressure cylinders are not then effective, while the consumption of coal does not seem to show the saving that would have been expected, when compared with ordinary engines doing similar duty on other lines; for instance, the Great Northern single engine takes trains of the same weight with the same consumption of coal and at a somewhat higher speed. But it must, of course, be borne in mind in making such a comparison, that the fuel used may not be of the same quality.

Mr. Stirling, of the Great Northern, has adopted an entirely different type of engine to those last described. Holding strongly that single engines are more economical not only in running, but in repairs, and that cylinder power is generally inadequate to the adhesion, he has designed his magnificent well-known class of express engines. They have single driving wheels 8 ft. in diameter, with a four-wheel bogie in front and a pair of trailing wheels, 4 ft. diameter, behind. The frames are single, and inside of one solid piece; the cylinders are outside 18 in. diameter and 28 in. stroke; and the valve gear is of the usual shifting link description. The boiler is of Yorkshire plates, 11 ft. 5 in. long and 4 ft. diameter, and the steam pressure is 140 lb.; while the tractive power per lb. of steam in the cylinders is 94 lb. The fire-box is of copper, and the roof is stayed to the outer shell by wrought iron radiating stays screwed into both; a sloping mid-feather is placed in the fire-box.

The tubes, 217 in number, are of brass, 1-9/16 in. diameter; and the heating surface is in the tubes, 1,043 square feet; fire-box, 122 square feet; total, 1,165 square feet. The fire-grate area is 17.6 square feet. The wheel base from the center of the bogie pin to the trailing axle is 19 ft. 5 in., and the weight in working order is, on the bogie wheels, 15 tons; driving wheels, 15 tons; trailing wheels, 8 tons; total, 38 tons. The tender weighs 27 tons. These engines are remarkable for their efficiency; the traffic of the Great Northern Railway is exceedingly heavy, and the trains run at a high rate, the average speed of the Flying Scotchman being fifty miles an hour, and no train in the kingdom keeps better time. "Those who remember this express at York in the icy winter of 1879-80, when the few travelers who did not remain thawing themselves at the waiting-room fires used to stamp up and down a sawdusted platform, under a darkened roof, while day after day the train came gliding in from Grantham with couplings like wool, icicles pendent from the carriage eaves, and an air of punctual unconcern; or those who have known some of our other equally sterling trains--these will hardly mind if friendship does let them drift into exaggeration when speaking of expresses." The author well remembers how, when living some years ago at Newcastle-on-Tyne, it was often his custom to stroll on the platform of the Central Station to watch the arrival of the Flying Scotchman, and as the hands of the station clock marked seven minutes past four he would turn around, and in nine cases out of ten the express was gliding into the station, punctual to the minute after its run of 272 miles. Such results speak for themselves, and for the power of the engines employed, and one of the best runs on record was that of the special train, drawn by one of these locomotives, which in 1880 took the Lord Mayor of London, to Scarborough. The train consisted of six Great Northern coaches, and ran the 188 miles to York in 217 minutes, including a stop of ten minutes at Grantham, or at the average rate of 54½ miles an hour. The speed from Grantham to York, 82½ miles, with three slowing downs at Retford, Doncaster, and Selby, averaged 57 miles an hour, and the 59 miles from Claypole, near Newark, to Selby, were run in 60½ minutes, and for 22½ consecutive miles the speed was 64 miles an hour. In ordinary working these engines convey trains of sixteen to twenty-six coaches from King's-Cross with ease, and often twenty-eight are taken and time kept. Considering that the Great Northern main line rises almost continuously to Potter's Bar, 13 miles, with gradients varying from 1 in 105 to 1 in 200, this is a very high duty, while, with regard to speed, they have run with sixteen coaches for 15 miles at the rate of 75 miles an hour. Their consumption of coal with trains averaging sixteen ten ton carriages is 27 lb. per mile, or 8 lb. per mile less than the standard coupled engine of the North-Western with similar loads. Mr. Stirling's view, that the larger the wheel the better the adhesion, seems borne out of these facts; thus to take twenty-eight coaches, or a gross load of 345 tons, up 1 in 200 at a speed of 35 miles an hour, would require an adhesive force of 8,970 lb., or 600 lb. per ton--more than a quarter the weight on the driving wheels. These engines are magnificent samples of the most powerful express engines of the present day.

The London, Brighton, and South Coast Railway Company has in the last few years had its locomotive stock almost entirely replaced, and instead of seventy-two different varieties of engines out of a total of 233, which was the state of locomotive stock in 1871. a small number of well-considered types, suited to the different class of work required, are now in use. Mr. Stroudley considers--contrary to the opinion once almost universally held--that engines with a high center of gravity are the safest to traverse curves at high speed, as the centrifugal force throws the greatest weight on the outer wheels, and prevents their mounting; also that the greatest weight should be on the leading wheels, and that there is no objection to these wheels being of a much larger diameter than that usually adopted; in fact, by coupling the leading and driving wheels where the main weight is placed a lighter load is thrown on the trailing wheels, thus enabling them to traverse curves at a high speed with safety, while it permits of a larger fire-box being used; and these principles have been carried out in the newest class of engines, especially designed for working the heavy fast passenger traffic of the line.

The modern express engines are of two types. The first is a single engine with 6 ft. 6 in. driving wheels, and leading and trailing wheels 4 ft. 6 in. in diameter and a wheel base of 15 ft. 9 in. The frames are single, with inside bearings to all the wheels; the cylinders are inside, 17 in. diameter and 24 in. stroke. The boiler is 10 ft. 2 in. long and 4 ft. 3 in. diameter; the fire-box is of copper with a fire-grate area of 17.8 square feet, and the heating surface is in the tubes 1,080 square feet, fire-box 102 square feet; total, 1182 square feet. The weight in working order is about 35 tons. These engines have a tractive power of 89 lb. per pound of mean steam pressure in the cylinders, and their consumption of coal with trains averaging nine coaches is about 20 lb. per mile. The next type of engine designed has coupled wheels under the barrel of the boiler 6 ft. 6 in. diameter, with cylinders 17¼ in. diameter and 26 in. stroke, and were found so successful that Mr. Stroudley designed a more powerful engine of the same class, especially to take the heaviest fast trains in all weathers.

The 8:45 A.M. train from Brighton has grown to be one of the heaviest fast trains in the kingdom, although the distance it runs is but very short, while it is also exceptional in consisting entirely of first class coaches, and the passengers mainly season ticket holders; it often weighs in the gross 350 tons, and to take this weight at a mean speed of forty-five to fifty miles an hour over gradients of 1 in 264 is no light work.

The engines known as the "Gladstone" type have inside cylinders 18¼ in. diameter and 26 in. stroke, with coupled wheels 6 ft. 6 in. diameter under the barrel of the boiler; the trailing wheels are 4 ft. 6 in. diameter, and the total wheel base is 15 ft. 7 in. The frames are inside, of steel 1 in. thick, with inside bearings to all the axles. The cylinders are cast in one piece 2 ft. 1 in. apart, but in order to get them so close together the valves are placed below the cylinders, the leading axle coming between the piston and slide valve. The boiler is of iron, 10 ft. 2 in. long, and 4 ft. 6 in. diameter; and the heating surface is, in the tubes, 1,373 square feet; fire-box, 112 square feet; total, 1,485 square feet. The grate area is 20.65 square feet, and the tractive power per pound of mean cylinder pressure is 111 lb. The weight in full working order is--leading wheels, 13 tons 16 cwt.; driving wheels, 14 tons 10 cwt.; trailing wheels, 10 tons 8 cwt.; total, 38 tons 14 cwt. The tender weighs 27 tons.

To enable these engines to traverse curves easily a special arrangement of draw-bar is used, consisting of a T-piece with a wheel at each end working in a curved path in the back of the frame under the foot plate; on the back buffer beam a curved plate abuts against a rubbing piece on the tender, through which the draw-bar is passed and screwed up against an India-rubber washer, thus allowing the engine to move free of the tender as the curvature of the road road requires; the flanges on the driving wheel are also cut away, so as not to touch the rail. In order to reduce the wear of the leading flanges, a jet of steam from the exhaust is directed against the outer side of each wheel. The center line of the boiler is 7 ft. 5 in. above the rails, and the tubes, of which there are as many as 331, are bent upward 1½ in., which permits expansion and contraction to take place without starting the tubes, and they are stated never to leak or give trouble. The feed-water is heated by a portion of the exhaust steam and the exhaust from the Westinghouse brake, and the boiler is consequently fed by pumps, is kept cleaner, and makes steam better. The reversing gear is automatic and exceedingly ingenious, the compressed air from the Westinghouse brake reservoir being employed to do the heavy work. A cylinder 4½ in. diameter is fitted with a piston and rod attached to the nut of the reversing screw, and a three-way cock supplies the compressed air behind the piston; this forces the engine into back gear, and by allowing the air to escape, the weight of the valve motion puts the engine in forward gear. There are no balance weights, and the screw regulates the movement. There is also a very ingenious speed indicator, which consists of a small brass case filled with water, in which is a small fan driven by a cord from the driving wheel; a copper pipe leads from the fan case to a glass gauge tube; the faster the fan runs the higher the water will stand in the tube, thus indicating the speed.

The author has been led to describe this engine fully on account of the numerous ingenious appliances which have been adopted in its design. In a trial trip on October 3, 1883, from Brighton to London Bridge and back, with an average load of 19½ coaches, or 285 tons gross, and with a speed of 45 miles per hour, the consumption of coal was 31 lb. per train mile, evaporating 8.45 lb. of water per pound of coal, and with as much as 1,100 indicated horse-power at one portion of the run. The finish and painting of these engines is well considered, but the large coupled wheels give a very high shouldered appearance, and as a type they are not nearly as handsome as the single engines previously described.

From the Brighton to the South-Western Railway is but a step; but here a totally different practice obtains to that adopted on most lines, all the passenger engines having outside cylinders, where they are more exposed to damage in case of accident, and, from being less protected, there is more condensation of steam, while the width between the cylinders tends to make an unsteady running engine at high speeds, unless the balancing is perfect; but the costly crank axle, with its risk of fracture, is avoided, and the center of gravity of the boiler may be consequently lowered, while larger cylinders may be employed. On the other hand, inside cylinders are well secured, protected, and kept hot in the smoke-box, thus minimizing the condensation of steam. The steam ports are short, and the engine runs steadier at high speeds, while with Joy's valve gear much larger cylinders can be got in than with the link motion. Thus modern improvements have minimized the advantages of the outside class.

The passenger engines for the fast traffic are of two types, the six-wheel engines with 7 ft. coupled wheels, and the new bogie engines which are being built to replace them. The former have 17 in. cylinders with 22 in. stroke, and a pair of coupled wheels 7 ft. in diameter, the leading wheels being 4 ft. diameter, and the wheel base 14 ft. 3 in. The grate area is 16.1 square feet, and the heating surface 1,141 square feet. The total weight in working order is 33 tons. The chief peculiarity of this type of engine consists in the boiler, which is fitted with a combustion chamber stocked with perforated bricks, the tubes being only 5 ft. 4 in. long. These engines are very expensive to build and maintain, owing to the complicated character of the boiler and fire-box, but as a coal burning engine there is no doubt the class was very efficient, but no more are being built, and a new type has been substituted. This is an outside cylinder bogie engine, with cylinders 18½ in. diameter and 26 in. stroke; the driving and trailing coupled wheels are 6 ft. 6 in. diameter, and the bogie wheels 3 ft. 3 in. The wheel base to the center of the bogie pin is 18 ft. 6 in.; the heating surface is, in the tubes, 1,112; fire box, 104; total, 1,216 sq. ft. The weight of the engine in working order is 42 tons.

The Midland Railway route to the North is distinguished by the heavy nature of its gradients; between Settle and Carlisle, running through the Cumberland hills, attaining a height of 1,170 ft. above sea level, the highest point of any express route in the kingdom; and to work heavy fast traffic over such a line necessitates the employment of coupled engines. The standard express locomotive of this company has inside cylinders 18 in. in diameter and 26 in. stroke. The coupled wheels are 6 ft. 9 in. diameter, and the leading wheels 4 ft. 3 in., the total wheel base being 16 ft. 6 in., and the tractive force 104 lb. for each lb. of mean cylinder pressure. The boiler is of best Yorkshire iron, 10 ft. 4 in. long and 4 ft. 1 in. diameter. The grate area is 17.5 square feet, and the heating surface is, in the tubes, 1,096; fire-box, 110; total, 1,206. There are double frames to give outside bearings to the leading axle, as in the Great Western engine, and the engine is fitted with a steam brake. The weight in full working order is--leading wheels, 12 tons 2 cwt.; driving wheels, 15 tons; trailing wheels, 11 tons 6 cwt.; total, 38 tons 8 cwt. The tender weighs 26 tons 2 cwt., and holds 3,300 gallons of water and 5 tons of coal. Latterly a fine type of bogie express engine has been introduced, with inside cylinders 18 in. diameter and 26 in. stroke, and four coupled driving wheels 7 ft. diameter. The total wheel base to the center of the bogie pin is 18 ft. 6 in. The grate area is 17.5 square feet, and the heating surface is, in tubes, 1,203 square feet, and fire-box, 110; total, 1,313; and the engine weighs 42 tons in working order. These engines take fourteen coaches, or a gross load of 222 tons, at 50 miles an hour over gradients of 1 in 120 to 1 in 130, with a consumption of 28 lb. of coal per mile. The London, Chatham, and Dover Company has also some fine engines of a similar type. They have inside cylinders 17½ in. diameter and 26 in. stroke; the coupled wheels are 6 ft. 6 in. diameter, and the bogie wheels 3 ft. 6 in., the wheel base to the center of the bogie pin being 18 ft. 2 in. The boiler is 10 ft. 2 in. long and 4 ft. 2 in. diameter, the grate area is 16.3 square feet, and the heating surface is, in the tubes, 962 square feet; fire-box, 107 square feet; total, 1,069. The boiler pressure is 140 lb., and the tractive force per lb. of steam in the cylinder 102 lb. The weight in full working order is, on the bogie wheels, 15 tons 10 cwt.; driving wheels, 13 tons 10 cwt.; trailing wheels, 13 tons; total, 42 tons.