BANKS AND GRADES

Evening Post, Volume CXXI, Issue 138, 12 June 1936, Page 9

BANKS AND GRADES

RAILWAY BUGBEARS

SURVIVALS FROM THE PAST

BRITISH EXAMPLES

{Written for "The Post" by I. C. E.)

The railwayman, for obvious reasons, dislikes steep grades on the lines over which he has to travel. They

are a strain on the engine going up and a strain on the brakes going down. Therefore tne railway engineer is re-, quired, when building a line, to avoid heavy grades to the utmost extent compatible with the public purse or | ■ whatever the source of the capital be, that is furnished him for his line.' New Zealand with its broken contours, will always present problems to the j builders of railways and roads, but England with its far flatter surfaces has some curious anomalies in sur-j prisingly steep grades on important ( lines, which cannot be explained in ( the ordinary way as necessitated by | the nature of the country. It isj perfectly intelligible why on the niain West Coast line from London to Scot.-, land a grade of 1 in 75 for five mlies, up Shap Fell cannot be avoided in; crossing the high country which t stretches across the North of England —much the same sort of obstacle that, confronts the North Island Main Trunk in the central plateau to the west of, Ruapehu. Similarly, there is the ten-, mile Beattock bank on the same West Coast line between Carlisle and Edin-; burgh. The mountain mass was too, wide to tunnel and there was no feasible way round, so the engineers, had to go over the saddle wuh tne best grade they could get. STRANGE ANOMALIES. But what is one to make of the steep bank out of Euston station on the L.M. and S. main line and the astound-, ing two miles of 1 in 30 up and 1 in 42 down beyond Newton Abbot on the Great Western main line from Lon-| don to Plymouth? .Or the steep pinch of 11 miles of 1 in 41 out of Glasgow on the London and North-Eastern I main inter-urban line to Edinburgh. , Or the Lickey incline of two miles ot 1 in 37 on the Midland main line from Bristol to Birmingham? When 1J" 100 is recognised as the most that can be allowed for a modern main line, circumstances permitting, these "banks" and others like them m the easy-going Old Country call for some explanation. The clue to the mystery lies in the early history of railway engineering In Great Britain, the u> ventor and pioneer of the railway and ( the locomotive, and the strange notions as they seem to us—of the possibili- 1 ties and limitations of the then new method of transport which have left their marks on the British railway system to this day. When the railway was first mooted in England by Trevethick it was doubted whether the steam locomotive would suffice, by the mere adhesion of the wheels to the rails, to draw a train, and a rack and pinion device was used. George Stephenson showed that this was unnecessary on the level and so "came the first practical locomotive— the Bocket—on the Manchester and Liverpool line. This was practically level all the way except for a sharp drop into Liverpool from Edge Hill. Up this incline trains were hauled by means of a stationary engine and ropes, such as are,..used on the Kel-1 burn cable tramway. Stephenson himself held that a ruling gradient of J 1 in 330 was about>the limit for nor-; mal steam locomotives and, if there, was anything much steeper, some other i means of traction would have to be adopted. Thus when George's brother,' Robert Stephenson, constructed the first important main line in Britain from London to Birmingham he tried to achieve this 1 in 330 ideal, with the result that enormously deep and long cuttings had to be cut. Even then, the first Stage from Euston Square to Camden Town, where the line had originally been meant to terminate, was •worked by stationary engines and cable haulage until 1843, when it was superseded. The year before that—lß42 — the Edinburgh and Glasgow Railway was opened with a line mainly level except for the last mile and a quarter into Glasgow, which fell at aj grade of 1 in 41 to 1 in 46. The reason for this was that the line, originally " designed to pass over the Forth and Clyde Canal to a high-level station, had to be depressed under the canal (instead of over) through the refusal of the canal company to allow an overbridge to carry the railway. So trains were hauled up a steep incline through a long tunnel by means of a hemp rope.

THE "ATMOSPHERIC" LINE. The hump on the main line of the Great Western between Newton Abbot and Plymouth was due to a different cause. In the days when this section was built by the South Devon Railway, afterwards merged in the Great Western, the steam locomotive had not proved itself supreme, and what we should today call cranky ideas had plenty of scope in the capital that was poured out like water to float the railway boom of the forties. So somebody managed to get the South Devon to try ■what was knoym as the "atmospheric" principle and run a more or less straight line, like a Roman road, over •hill and down dale. In the atmospheric system a cast iron pipe, of about 20 inches bore, was laid between the rails. On the upper side of the pipe ran a continuous slot from end to end. A piston fitted the bore and «n arm connected the piston with the coaches of the train on the rails. A leather flap, hinged at one side, closed the slot except where the arm attachment went through to the piston. The | sir was exhaused from one end of the | pipe by pumps at a central station and ] atmospheric pressure acting on the, piston propelled the train. It worked well enough until the weather affected the leather flap and the piston rings of cupped leather. The ingenious de-j vice was abandoned in 1848 and the Great Western was left with a legacy of gradients that have taxed the strength of the steam locomotive ever Since. THE STEEPEST GRADIENT. The steepest gradient on any line In Great Britain is on the old High Peak railway in Derbyshire, now part of the L.M. and S. system. Here is what Is known as the Sheep Pasture Incline of 1 in 8 for 550 yards and 1 In 9 for half, a mile, something much worse than the Rimutaka incline. Np locomotive is remotely possible here 'anil cable haulage is still used. On the same line is the Hopton incline of 1 in 14, which is worked by locomotives with limited loads. Here it was found that the locomotive of the 2-4-0 type would sometimes manage to run its front wheels over the brow of the bank, to find that the rest could go no further. It would then have to back down and try again with a more strenuous effort.

Most of these "out-sizes" in inclines in Britain are surmounted in these days by the much more powerful engines that have come into use since the war, but some banks still need the special assistance of banking engines, *uch u they use to push the Main i Trunk expresses up to Johnsonvllie. i For the Liokey incline on the Bristol•BlrmJngham main line—two miles of

1 in 37—specially designed four-cylin-der ten-wheel coupled locomotives, known locally as "Big Berthas," are employed. On other inclines, like those in South Devon, pilot engines are added when the train load exceeds certain limits. Electrification of the line to cope with grades is not standard practice in Britain. Elsewhere, however, as in France, Italy, Switzerland, and parts of Spain, where coal is dear and water-power plentiful, electric traction is found to be a great aid to the conquest of the grade. In this way in the United Slates also the northern transcontinental lines, like the Chicago, Milwaukee and St. Paul, and the Great Northern, have long electrified sections across the Rockies and through the Cascades.

Sometimes the railway engineer ( even in these times is up against the . impossible, when he is called on to cross a high mountain range by ad- i hesion traction alone. ; Such, for , example, was the problem of connect- ( ing AUntina and Chile across the Andes at a point where the range is both steep and high and there are no 1 mountain passes feasible and the mere | mass of mountain bases forbids direct, _ tunnelling. Here resort must be had ' to other methods of traction, and in ' the Andes the rack system, the oldest ; of all, is employed for many miles, cog wheels on the engine meshing in a, l triplicate rack laid between the pair > 1 of rails. The same system is used on i the line between Beyrout and Damas-1 } cus where it crosses the seaward ( Lebanon Range at a height of 6000 ft. , The mountain section is over twenty j miles long, so that a tunnel would be j out of the question. Only where a j mountain barrier divides rich and ] populous countries, as in Europe and ( Western America, do long tunnels be- , ! come feasible solutions. Such are the Simplon, the Loetschberg, the St. Gothard, the Mount Cenis, and the Arlberg in Switzerland, the Apennine tunnel in Italy, the Canfranc tunnel under the Pyrenees between France and Spain, and the Moffatt, Cascade, and Connaught tunnels in Western America. Th'e Otira tunnel in New Zealand ranks in the world series and has amply justified itself a l , the only I way through. The Tawa Flat tunnels will pay in the long run. What about j the Rimutaka?