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The New Zealand Railways Magazine, Volume 11, Issue 6 (September 1, 1936)

Striking Contrasts in Grades. — Great Britain and New Zealand

page 57

Striking Contrasts in Grades.
Great Britain and New Zealand.

The two grade diagrams shown in the illustration are intended to give some idea of the difficulties to be overcome in railway working in this country as compared with many other lands in which high speeds are less restricted by nature's formidable barricades in the form of high hills. The diagrams show to exactly the same scale the ups and downs on the route of the justly celebrated non-stop four-hour run of the “Silver Jubilee” from King's Cross to Newcastle as compared with the rises and falls in an equal distance along the route of the Auckland “Limited” Express. When properly understood they indicate that the performance of the latter train, though taking more than twice the time to travel the same distance, is by no means to be despised.

In the first 4 1/2 miles out from Wellington the line rises 513 feet, the average grade being about 1 in 40 for four miles of the ascent. The corresponding British train nowhere rises to this extent in any part of its run. Incidentally it might be mentioned that the Christchurch-Dunedin express reaches 382 feet at Chertsey in crossing the Canterbury “Plains.” The London-Newcastle route barely reaches this elevation at its highest point near Grantham. To eliminate the short but sharp climb from Wellington to Johnsonville a deviation costing #1,420,000 is nearing completion, but even this expenditure will take only about 10 minutes off the time taken by the “Limited” on its 426 mile journey, its real value being in the greater loads that can be hauled on goods trains. The greatest elevation reached is just over 2,670 feet at Waiouru after climbing 2,433 feet in the 100 miles from Feilding. An elevation of 2,670 feet is again reached near Pokaka, and 2,647 feet at National Park. The southbound “Limited” also climbs 935 feet in 20 miles from Te Kuiti to an elevation of 1,113 feet at Poro-o-tarao, including a 7 mile pull and several shorter ones up a grade of 1 in 70. Again from Kakahi to National Park there is a steady rise of 1,774 feet in
Diagram showing (above) the grades on the London-Newcastle Section of railway, England, and (below) the grades on the Wellington-Te Kuiti section of the North Island Main Trunk Line, New Zealand.

Diagram showing (above) the grades on the London-Newcastle Section of railway, England, and (below) the grades on the Wellington-Te Kuiti section of the North Island Main Trunk Line, New Zealand.

22 miles, terminating with the climb up the celebrated Raurimu “Spiral” of 714 feet in the last 7 miles. On the whole run shown on the diagram, 130 miles are on grades of 1 in 100 or steeper, 85 1/2 miles of 1 in 70 or steeper and 18 miles of 1 in 50 grades or steeper. The effect of the grades on train speeds may be seen from the speeds computed for an “Ab” engine hauling a 200 ton train as follows:—
20 m.p.h. up a 1 in 50 grade.
25 1 in 60
30 1 in 70
35 1 in 100
40 1 in 135
45 1 in 220
50 on level and easy grades.

Nor are the grades the only cause of restricted speeds. The same type of rough country also calls for sharp curves. The milage of curves on the run illustrated is as follows:—

53 miles less than 15 chain radius

27 10
of 7 ½

The speed permissable on curves varies as the square root of the radius. When R. is the radius in chains the average speed in miles per hour allowed on the railways of the world is approximately 11√R. The speed on the New Zealand railways reaches 11 1/2√R. on curves of 13 chain radius and upwards, and slightly less on sharper curves. The South African railways fix the speed at 10√R. The page 58 fastest speeds in the world on curves are run on the Java National Railways, 12√R. On Australian lines the speeds permitted on curves are generally lower, especially on the sharper curves. The speeds on curves on the New Zealand railways are:

On straight and curves 20 chain radius and over, 50 m.p.h.
On curves 16 chain and under 20 chain radius, 45 m.p.h.
On curves 13 chain and under 16 chain radius, 40 m.p.h.
On curves 11 chain and under 13 chain radius, 35 m.p.h.
On curves 9 chain and under 11 chain radius, 30 m.p.h.
On curves under 9 chain radius, 25 m.p.h.

These speeds can be run as the result of the high standard of maintenance of track in New Zealand, as has been recognised by numerous Railway experts who have from time to time visited these shores. A less expert but even more gratifying testimonial to the running qualities of both track and rolling-stock was given by a layman, who, while a daylight express was parked for the night at Ohakune at the time of the 1924 strike, complained of the slow travelling as inexcusable in view of the fact that the track was so level and so straight. When taken into the engineer's office and shown the plans and sections of the track he had just passed over, he was amazed at the combination of corkscrew and switchback and was devoutly thankful for his safe arrival.

The diagrams do not set out to show the highest or steepest grades on the respective systems, nor will such a comparison mean much, since in Great Britain of the 18 places in the whole 20,000 miles of British railways over 1,000 feet above sea-level, not more than five are on what could be termed main lines, namely the Druimuachdar Summit, 1,484 feet, near Dalmaspidal and the Slochd Mhuic, near Carr Bridge, 1,315 feet, both on the PerthInverness line; and those at Hindlow, 1,192 feet, on the Derby-Manchester line, Ais Gill, near Hawes Junction, 1,167 feet, Leeds-Carlisle (old Midland Section); and at the Beattock Summit, 1,014 feet, Carlisle-Carstairs line. All five are on the L.M.S. railway. The remainder are all either in the Highlands of Scotland or in the mountainous parts of Wales on Branch lines and none of these rises more than 1,500 feet above sea-level. The rack railway to the summit of Snowdon, 3,540 feet, cannoi of course be considered among the speed lines.

By way of contrast to these, in addition to the summits on the Wellington-Auckland route already mentioned, may be cited the 1 in 35 climb to 1,890 feet at Mamaku on the Rotorua line, and the 2,434 feet to the Arthur's Pass portal of the Otira Tunnel on the Midland line. It is of interest to note that the point at which the latter line leaves the Canterbury “Plains” and takes to the hills it has already reached, at Springfield, a height of 1,258 feet, or 244 feet above the well-known Beattock Summit on the Caledonian line and 339 feet above the Shap Fell Summit, 919 feet on the Leeds-Carlisle railway, London-N.W.

Does smoking shorten life? Antitobacs say it does. Apropos of that the death at Swansea (Wales) of Miss Elizabeth Dillwyn at the age of 90 was recently recorded. The old lady, a well-known Swansea identity who formerly took an active part in local public affairs, was an inveterate smoker, but had no time for cigarettes. She used to say: “Smoking cigarettes is like drinking beer out of a thimble!” Many of your dyed-in-the-wool smokers are like that. Well, brands may come and brands may go, but “toasted,” like the “Brook,” goes on for ever! It's always wanted! These famous tobaccos, Cut Plug No. 10 (Bullshead), Cavendish, Navy Cut No. 3 (Bulldog), Riverhead Gold and Desert Gold merit their outstanding popularity; all are remarkable alike for flavour and bouquet, also for their comparative freedom from nicotine eliminated in the course of manufacture by toasting, the manufacturers’ exclusive process which does so much to safeguard the smoker. But don't be imposed upon! Refuse all substitutes. The only genuine toasted brands are those above enumerated.*

As illustrating the slowing-up effect of even moderate grades and curves the trial run on the King's CrossNewcastle line may be cited. The average overall speed was 67 miles per

page 59

hour, but to attain this run a speed of over 80 miles per hour was run for over 120 miles, while the maximum instantaneous speed was 112 miles per hour. The average speed was therefore 60 per cent, of the maximum on a non-stop run. Nothing like these speeds could, of course, be attempted on a 3ft. 6in. gauge. To get a vehicle of sufficient carrying capacity both the height of the centre of gravity and the amount of lateral overhang have to be greater in proportion, thus reducing the safe speed. Nevertheless it is worth while to note that the average speed of the Christchurch-lnvercargill train is 66 per cent, and of the “Limited” express 60 per cent, of the maximum authorised speed of 50 miles per hour even after including the numerous stops required to give reasonable service to dwellers in inland towns.

The only long-distance trains that regularly exceed the 29.6 miles per hour of the Auckland “Limited,” and the 29.7 miles per hour of the Christchurch-Invercargill express (both including stops), on a 3ft. 6in. gauge cover the 373 miles between Tokio and Kobe (Japan); the 512 miles between Batavia and Sveravaja (Java), both 41.5 miles per hour, and the 455 miles between Johannesburg and De Aar (South Africa), 35.6 m.p.h., all inclusive of stops. It may reasonably be claimed, therefore, that for anything approaching comparable conditions the principal New Zealand express trains are well up arrrong the fastest in the world.

The Film In Railway Education.

The London, Midland and Scottish Railway—has for some years made use of cinema films for staff educational purposes, and this winter the special “film educational unit” devised by the Euston authorities is visiting no fewer than forty important centres in England, Wales and Scotland. This time the films are in sound, and two of the most important films showing are (1) “A Study in Steel,” which records the building of one of the latest type of locomotives at the Crewe Works; and (2) “Permanent Way,” a fascinating story of the 19,000 miles of track which go to form the L.M. and S. system lines.