PUBLIC RECORD OFFICE
Reference :--
TICO. 882
PUBLIC RECORD OFFICE, LONDON
ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC- COPYRIGHT PHOTOGRAPH-NOT TO
See Table
92
10 passengers to a ton) to 3,118 tons were carried to an average distance of 32-26 miles; we thus have--
III. attached nearly to
"to Memo-
randum of 17th April Jost.
Goods Passengers
■
TODI. Miles. 16,730 x 36:55 = 611,481 3,118 × 32-26 = 100,586
712,067
Total tons of goods and passengers conveyed one mile
The total working expenses during 1884 were Rs. 288,259, equal to Rs. 0-405, or very annas 6 pie per ton per mile, an amount which, it will be noticed, is more than double the cost of working the Haputale Extension as guaranteed by Mr. Prestage. In this connexion it may be noted that the only item in the working expenses susceptible of reduction by improved engines is that of "locomotive power," and admitting the "Climber "to be so successful as to reduce the expenditure under this head to Rs. 47,710 per annum, or half the cost of that item in 1884, and that no increase is entailed under the head of Maintenance by the use of so heavy an engine, the total cost of working expenses would still be Rs. 240,549, equal to Rs. 0·337, or very nearly to 5 annas 5 pie per ton per mile.
8. In the filth to ninth paragraphs of his letter, inclusive, Mr. Prestage discusses the question of the track which he stipulates should be provided for him; he considers that one 8 feet wide would be sufficient, and that a sum of 2,3507. per mile would be ample to cover its cost.
9. I will afterwards discuss the width of the track necessary, but for the present will confine myself to the eighth paragraph of Mr. Prestage's letter, in which he refers to the amount of excavation necessary in comparison with that needed for a broader gauge; here Mr. Prestage states that "forming a track 8 feet wide on a fairly bluff face, say " in 10 costs only half as much as forming one a little over 11 feet wide, and only one- "fourth as much both in time and money as one 16 feet wide."
a
This point is, I think, put a little unfairly by Mr. Prestage. I admit that, if the contour of a hillside was in so regular a circular arc as to permit the railway to follow it closely "bench" cut out of the face of the hill, and if the increased width of this "bench " necessary for tracks 11 and 16 feet wide was obtained by cutting into the bill- side only, the excavation would be in the proportions given by Mr. Prestage, but in practice this would not be the case as the increased breadth would be obtained by widening on both sides of the centre line.
10. Even upon hill cart roads in Ceylon, where reverse curves of about 20 feet radius, and even sharper than this, in the case of zig-zags, are used, and where, moreover, the curves need not, as they must upon railways, be accurate aros of circles, "through" locally called "double cuttings, either through saddles or spurs too abrupt to be otherwise passed, are by no means of uncommon occurrence.
11. Upon a railway such as the extension to Haputale, where the country is unusually rugged and broken, where the curves even, though they be of so sharp a radius as 70 feet, must necessarily be accurate arcs of circles, and where, moreover, between reverse curves a piece of straight line, certainly not less than one chain in length (but 100 feet is much better) must be given to allow of the gradual change in super-elevation from one rail to another. Such cases as that mentioned by Mr. Prestage would be of the rarest occurrence, and, in the vast majority of instances, "through or "double cuttings would be obligatory.
12. In such a through or double cutting in earth, with slopes of 1 to 1, 10 feet deep at the centre line, the transverse slope of the ground being 1 in 10, the areas of excavation necessary would be-
For a base 8 feet wide
For a base 11 feet wide
For a base 16 feet wide
·
Superficial Feet.
-
-
184.14 223.60 264.20
These areas are to each other as I to I 21 and 143 respectively.
In other words, the excavation for a cutting 16 feet wide would be only 1.43 times that necessary for a cutting 8 feet wide, instead of four times as much, as stated by Mr. Prestage..
The steeper the transverse slope of the hill-side the less will these proportionate differences be, and, as upon the Haputale Extension, so gradual a slope of the hill side as 1 in 10 is rarely met with, I will take as an illustration the cutting at 5 miles 49 chains Paper XI, of on that line where the slope of the hill-side is very nearly 14 to 1, the depth of the
See Sessiona!
1886.
93
cutting at the centre line being 24-77 feet, here for an earth cutting having slopes of Figure 2, I to 1, the areas for different widths of base will be--
For a base 8 feet wide For a base 11 feet wide
For a base 16 feet wide
For a base 18 feet wide (that shown in the figure)
shown at
page 12.
Superficial Feet.
1468.08
1624.36
1893-16
1980:50
These areas are to each other as I is to 1106, 1:29, and 1:35 nearly respectively, or, in other words, the excavation for a cutting 16 feet wide would be only 129 times that for a cutting 8 feet wide, instead of four times as much as stated by Mr. Prestage.
13. Before leaving this part of the subject, it may be well to remark that in a rock cutting only 8 feet wide, the cost of excavation per cubic yard would, in my opinion, be very appreciably higher than in a cutting 16 feet wide, because in the former case a larger per-centage of the shots necessary would be fired in the corners or re-entering angles of the "gullet," where they would be less effective than if fired at a broad open
face.
14. I do not, however, consider the 8-feet width of track proposed by Mr. Prestage to be sufficient, for the following reasons,-
The width of roadway necessary for any railway may be viewed from two aspects, the first having regard merely to the width of the vehicles proposed to be used thereon, and the second having regard to the breadth required for the permanent way, drainage, &c. Viewing the question in the first case from its first aspect, I would remark that Mr. Prestage, in paragraph 4 of the Enclosure No. 4 to his letter, refers with great satisfaction to his vehicles being inade 6 fect in width. Now in cuttings through rock, which are frequently excavated with vertical or nearly vertical sides, a cutting 8 feet wide would only allow a margin of one foot on each side of the carriages.
No plate. layers could therefore remain in such cuttings while a train was passing, and any passenger incautiously putting his head out of the carriage window would be inevitably killed. Moreover, in the case of accident, or break down of a train in such a cutting, the passengers would be, as the carriage doors could not be opened for want of space, shut up until assistance could be obtained, and they could be extricated. I may remark that on a railway 5 feet 6 inches gauge, where the carriage bodies are usually 8 feet
6 inches wide, a margin beyond them on cach side of 2 feet 8 inches is given.
I am aware of no good reason for departing from this rule in the case of a narrow gauge railway, and viewed from this aspect only the rock cuttings should have a base 11 feet 5 inches in width.
Turning now to the second aspect of the question.
The sleepers used on the Darjeeling Himalayan Railway are, I understand, 4 feet 6 inches in length; they should have beyond their ends a foot of ballast in order to prevent lateral displacement of the roadway, the top breadth of the ballast would thus be 6 feet 6 inches: assuming the ballast to be 1 foot 6 inches in depth-and with less than this a good foundation could not be obtained—and that its slopes were packed up with stones to a slope of to 1, its bottom breadth would be 8 feet, and beyond this ou each side spaces at least 1 foot 6 inches in width, though 2 feet would be far preferable, must be allowed for drainage; viewed from this aspect therefore the bases of the cuttings must be 11 or 12 feet wide.
15. Leaving aside all consideration of the cost of tunnels, which might and I think would in certain cases be necessary, I venture to say that the cost of forming a track 12 feet wide, from Nanu Oya to Haputale, with gradients not exceeding 1 in 30 and with curves of 70 feet wide in radius, having pieces of straight line not less than one chain in length between curves in reverse directions, would be at least Rs. 60,000 per mile, if indeed this sum were not considerably exceeded.
This cannot, I think, be deemed an extravagant estimate, when it is remembered that the cost of many cart roads in the hill districts of Ceylon, on which gradients of 1 in 20 See Sessional are used, and which are subject to the very elastic conditions regarding curves pointed Paper out in paragraph 10 of this report, has been, excluding land and compensation, upwards XLIII. of of Rs. 20,000 per mile, while in one instance the cost was Rs. 36,210 per mile.
16. If to this sum of Rs. 60,000 the possible amount payable to Mr. Prestage in the terms of his own offer, viz., 4,350, equal at 18. 6d. per rupee, to Rs. 58,000, be added, the total cost of the line would be Rs. 118,000 per mile, even at the lesser sum
❘ 28223.
1880, pages 88 and 89.
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