This paper, from The Proceedings of the Incorporated Association of Municipal and County Engineers, Volume XVII, 1890-91, was written by William Newby Colam, an engineer who participated in the construction of several UK cable tram lines. In this paper, he concentrates on the Edinburgh Northern Cable Tramways, which he designed and built. He presented the paper on 26-September-1890.
From Proceedings, Incorporated Association of Municipal and County Engineers, Volume XVII. -- 1890-91. (London, England).
EDINBURGH NORTHERN CABLE TRAMWAYS.
By WILLIAM NEWBY COLAM, Vice-Pres. Soc. Engineers,
|Horses||=||85.5 per cent. of gross receipts.|
|Steam engines||=||64.5 per cent. of gross receipts.|
|Cable||=||46.5 per cent. of gross receipts.|
The last line constructed is the second one in Edinburgh. The introduction of cables is now being actively considered for several important districts.
The total number of miles of cable tramways in successful operation is 501, over which last year it is estimated that not less than 794,245,000 people were carried, or nearly twice as many passengers as were carried on the tramways of the United Kingdom.
Trinity Route. -- This first line constructed meets Princes Street in Hanover Street, and proceeds north over the hill in George Street, and then descends the steep incline of Pitt Street. Passing Henderson Row, where the cables branch off to the engine-house, it takes curves of 195 feet and 80 feet radii, and crossing the old bridge of Canonmills, which is the lowest point on the route, it ascends easier grades to the Trinity terminus. The district round the southern half of the line is completely built over, and the northern section is being quickly developed since this line commenced operating. The cable passing along this line traverses eighteen curves, of radii varying from 80 feet to 980 feet, the smallest curve being less than a right angle. It is also diverted at various places by nine large pulleys. The total height ascended is 187 feet. The length of track is 3 miles.
Stockbridge Route. -- This line also starts from the main street of Edinburgh, and travels parallel and over almost identical grades as part of the other route. After passing round 100 feet curves into the Royal Circus, the lines are almost entirely a series of curves passing through steep and very narrow roads, thickly populated on all sides. The line then crosses another old bridge at Stockbridge, where the cable leaves for and returns from the engine-house ; the route, though curvy for a time, is almost level. The cable on this line has to traverse 28 curves, of radii ranging from 80 feet to 400 feet; it also is directed by the same number of large pulleys as the other line. The total height ascended on this route is 173 feet, and the length of the track is 2.4 miles.
The engine-house from which these two lines are operated is in Henderson Row, 400 feet from the Trinity route, and 1650 feet from the Stockbridge route. In the first case, the cable coming into and going out from the driving machinery, travels in a closed tube to the main line in Pitt Street. There it is directed in from the right and out to the left. Arriving at Trinity terminus, it is diverted by an 8 foot 6 inch pulley to the return line. On passing Henderson Row again, the cable is not interrupted, but proceeds directly to Princes Street, where again it is directed down to the depot, by passing around another 8 foot 6 inch pulley. The Stockbridge cable, on leaving the depot, instead of passing into a closed tube, is conducted along a single line of cable track, and on arriving at Claremont Place there is a passing place. Proceeding south-westward, the cable going and returning still travels in a single tube, and passes round a gentle curve. On reaching the main line at Stockbridge, the cable dips under the up line, and is directed to the down line. At the two termini of this line the cable is diverted much in the same way as on the other route.
The cars operating the Trinity route take the cable at the up or down main lines. At Trinity terminus the driver opens his gripper and the cable is adjusted so that it leaves the gripper automatically. The return cable is taken after passing by gravity through the siding. The cable does not again leave the gripper until the siding at Princes Street is reached, when on opening the gripper the car is taken by gravity to the end. When the car is required to leave, the cable is taken by simply lowering the gripper. On arriving at Henderson Row, where there is a break in the continuity of the cable, the gripper is opened and the car passes by gravity to the cable returning from the depot.
On the Stockbridge route the cars take the cable outside the depot, and travel along the single line and through the passing place to the commencement of the 60-feet curve which joins this single line to the up-hill track on the main line. Here the driver brings his car to a standstill, and almost at the same operation of releasing the main cable, he takes an auxiliary cable which is laid in this curve. He proceeds with his car around the curve at a reduced speed, and at a certain place on the main line stops again and takes the main cable. After this operation the mode of working is precisely the same as on the other route. Whilst referring to the plans adopted in these cases of working the cars at the termini, at the places where the cables leave and return to the tracks, and in passing round the 60-feet curve from the siding, the author wishes it to be understood that there are many other ways in which these could have been operated.
It must not be supposed that the author has considered it necessary to have an auxiliary cable to work cars round short curves. At the junction of the single line from the depot with the main lines on the Stockbridge route, powers were obtained to connect with two curves, but the author thought traffic at the corner was at times rather congested, and he decided to use only one curve to complete the connection. In adopting this plan, he has demonstrated the practicability of conveying the traffic over systems of cable tramways which may be receiving their motive power from machinery stations widely separated. By such a means, there is no reason why cable may not be adopted for working complete systems of tramways requiring cars to pass over varying routes.
The author has had prepared, specially for this occasion, full-sized representations of the road surface, and a cross section of the bed of road aud cable tube. The road surface has been very faithfully depicted, in fact it is as nearly as possible a piece of the track itself, and requires no imagination to realise what is necessary to convert a horse line to a cable route. The author has also provided the shoe of an Edinburgh cab-horse, which is useful in comparing with the size of the necessary slot and rails forming it. It will be seen, as has been demonstrated by actual results, the slot construction cannot in any way be detrimental to street traffic. Cart-wheels crossing at acute angles over ordinary tramway rails, when the tread of rail has not worn equally with the guard, sometimes receive wrenches better known than appreciated, but at no time of the life of the slot can such be caused by the rails forming it. In the first place a tramway rail groove is 1 inch wide, and the corners are rounded. Secondly, the tread is always wearing, and the groove rounding more and more. But the slot is only 5/8 of an inch wide, and the edges of rails forming the slot will always remain square as constructed at first. It will thus be seen that the narrowest wheels may cross the slot at any angle without the driver in charge being aware of their existence. From the full-sized cross section of the road and tube, it will be seen that the tube is made of concrete, and that the upper part of the construction, with the exception of slot. is little more than the ordinary track for a tramway to be worked by horses. The tube is 19 inches deep from the surface of the road, and 9 1/2 inches wide. In the concrete forming the tube are embedded, at intervals of 3 feet 6 inches, cast-iron tube frames, to which the slot rails are bolted. The cast-iron frames are all lined up in place before the concrete is poured in, consequently the whole becomes a homogeneous mass of concrete and iron, which prevents subsidences or closing in of the slot rails. The extreme over-all depth of the tube from the road is 26 inches. Under the bottom of the tube is laid a 6-inch clay pipe, which is connected with and drains recesses in the concrete. These recesses receive the pulleys for supporting the cable, and are placed 50 feet apart. The pulleys for conducting the cable round curves are of course spaced as experience dictates for varying conditions and radii. In dealing with sharp curves it is not necessary to have openings through the road to get at the pulleys. The author devised a subway between two tracks, from which pulleys may be renewed or adjusted. This has proved a most convenient arrangement, and was not costly.
The track rails are of an ordinary girder type, and are 6 inches deep, and weigh 75 lb. per yard.
The slot rails form an important part of cable construction, those used form the subject of a patent of the author's, and are intended to lessen the cost of tube construction, by reducing the depth of tube, and forming in the rail itself a means of supporting the gripper in going round curves. This is done by setting back the bottom member of the rail, which allows a friction roller on the gripper to take the lower vertical plane to the right or left, according to the direction of the curve. These rails are made of steel, and weigh 39 lb. per yard. They are fished with plates on the outside only, weighing 34 lb. each.
The tube frames supporting the slot rails are made of superior cast iron. The centre web is 1 inch thick, and the whole weight is 135 lb. At each side there are recesses for receiving special ties for keeping the track rails accurately in gauge with the slot. The supporting pulleys are 14 inches in diameter, and are made V shape in the tread. They are of cast iron, and are specially designed to be adjustable in the tube, and to absorb any sound created by contact with the cable. The journals revolve in boxed lignum vitae bearings, with a special arrangement for lubricating. These pulleys have proved very effective in absorbing sound, and they will run three months without attention.
The pulleys for the curves are 14 inches in diameter, and are so arranged that the portion worn by the cable can be renewed without the more expensive centre. On the worst curves the outside sleeves of these pulleys last over sixteen months.
When two tubes are brought together, such as in the cases of the down lines at Priuces Street running into the up lines, or where, as in Hamilton Place, a single line enlarges, for a time, into a passing place, the slot junctions have been constructed so that the slots need not be wider than 5/8 inch.
The large diverting pulleys are made of cast-iron, with jaws bolted on in segments, with wood treads. They are built in segments to be removable in small parts.
The terminal pits for holding the diverting pulleys are built of concrete on the one route, and of brick on the other. Their internal dimensions are 19 feet long by 11 feet broad by 8 feet deep. The roofing is composed of rolled joists, jack arches, and buckle plates. On the Stockbridge route large sewers were found in the roads where it was desired to place these pits. The Burgh Engineer kindly gave his consideration to the matter, and a simple departure from the designs enabled the pits to be constructed without increasing their sizes, or injuriously affecting the sewers. The pits at Stockbridge and Henderson Row, containing the machinery to divert the cable from and to the depot, are somewhat larger than the terminal pits. In many cases these pits would be entirely dispensed with.
The machinery in the Stockbridge pit is more complicated than the others, as it contains gear for driving the auxiliary cable working round the 60-feet curve. The power required to propel the auxiliary cable is derived from gear on one of the diverting pulleys, which is kept in motion by the friction of the main cable on the periphery of the diverting pulley. Whilst describing this portion of the route, it will be well to draw attention to the points where it is necessary to release the cable going to the depot, and gravitate to the portion of the cable returning from the depot. If a driver should neglect to do this, there is danger of injuring the cable. To avoid this, the author has designed a combination of electric bells and stops, which first warn the driver, and in ease of his not heeding, bring the car to a stop. The apparatus works well, and is set in operation the moment the cable is removed out of its normal line of travel.
The cables now used on these lines are those known as Lang's patent, and are made by Messrs. Cradock and Co., of Wakefield. The author has now had considerable experience in working cables, and he is of opinion that there is not at present a better make, for cable tramway purposes, than the Lang lay. It is necessary to use a cable which will give a maximum amount of wear without fracturing the wires. This the Lang rope does by enabling, on a given diameter pulley, larger wires to be used, and at least the same flexibility as the old make of rope. The cable used is made of the very best patent improved crucible steel wire, laid round a hempen core, in six strands, each of 13 wires (7 round 6). The wires stood a tensile strain of 80 tons per square inch ; torsional tests of 35 twists in 8 inches, and 4 1/2 times bent over its own part. The lay of rope is 9 inches, and the circumference 3.1, inches. Specimens of new and worn rope are produced. It will be noticed that, as the life of the Lang rope is extended, the frictional surface area increases, until it should eventually approach the appearance of a bar of steel, the lay of the wires in the strands permitting such wear without the wires being cracked on the crowns of the strands, as in the old form of rope.
The cars used are of the bogie type. They are fitted with two sets of powerful brakes, one set acting on all eight wheels, and the other on the track rails. From the axles of the bogies are suspended the frames for receiving the grippers.
The grippers are a very important part of the mechanism in
cable tramways. The one adopted in this case is a patent of the
author's, who believes that a good gripper should possess the
1. It should require unskilled labour to operate it.
2. It should be removable from the car in less than one minute by the driver, without special tools, which may be mislaid.
3. It should be entirely detached from the cable when a car is at a standstill, so as to avoid unnecessary wear on the cable.
4. It should be able to pick up the cable at almost any part of the line without any special gear.
5. All parts wearable or breakable should be cheaply and quickly substituted.
6. The mechanism through which the driver applies his grip on the cable, should not be such as to admit of a sudden seizure of the cable, and thereby causing fracture of wires.
7. It should take up as little room as possible, to enable shallow tubes to be adopted.
8. It should contain a rolling arrangement for supporting the gripper in going round curves.
It is believed that this gripper complies with all these conditions. Referring to the gripper, the driver in operating the hand-wheel raises or lowers a nut by the square spindle. Attached to the nut are two rods, which raise or lower the bottom jaw of the gripper, the upper portions of which slide through openings in the plate which has the upper jaw casting bolted to it. The plate rests on angles suspended from the axles of the cars, and is firmly held down in its place by wedges, which are forced in or out by the driver through screw spindles and inclined slots. When the wedges are withdrawn, the whole gripper will rise by the action of the hand-wheel. The bottom jaw can be lowered out six inches, and by that means the cable can be picked up, because the moment the rounded bottom of the jaw touches it, the cable ascends into its place in the gripper. The roller revolves on the slot rail on going round curves, and takes the torsional strain close to where it is created by the cable. The dies by which the cable is gripped are of the softest cast iron, and last on an average about six weeks. The sectional area of the steel shank, where it works in the slot, is 4.92 square inches. These grippers have heen found efficient at work and under the maintenance test.
It is very essential for the proper working of cable tramways that special attention be given to the selection of valve gear to be used. In this case the author selected that known as Dr. Prodi's Automatic Expansion Gear, a small model of which is shown, and well illustrates the action. This valve gear has proved most effective in controlling the varying conditions of traffic, aud requires very little attention. The valve gear and the engines, which are a pair of high-pressure horizontals, 20 inches by 40 inches, were made by Messrs. M'Culluch, of Kilmarnock. These engines are arranged so that either can work the two routes, and that one of the two routes can be thrown off or on without interfering with the other. The driving pulley used is 10 feet 0 inches in diameter, and of the V type, around which only a three-quarter lap is made with the cable. The jaw of the pulley is removable in segments, and is lined with white metal, which can be easily renewed when the cable wears to the bottom. The loss of metal is very little, as the segments are re-melted with a small addition of new metal, and poured again into place. The bottom of the V is filled with soft wood, upon which the cable bottoms. This arrangement has been found effective in preserving the cable in shape, without inducing slip. The cable goes direct to the driving pulley, around which it passes a three-quarter turn; it is then directed down again over an idle 10-foot pulley to the automatic tension pulley around which it takes a half-turn and leaves the engine-room. The effective weight on the tension is only 7 cwt.
From the foregoing description it may be observed that the
Edinburgh Cable Tramways are working under the following varied
1. On gradients as steep as 1 in 11.
2. Over perfectly flat roads.
3. Round small right-angled curves.
4. Over old bridges with the crowns not twelve inches from the road surfaces.
5. Two routes at considerable distances apart being worked from one engine in the same depot.
6. Single lines with passing places.
7. Cars being worked at reduced speed round a sharp curve.
In addition, cable routes abroad cross each other ; cable cars run in conjunction with horse systems and take on the cars from the horses. There are, therefore, few circumstances met with in street traction that the cable has not conformed to.
The cost of constructing and equipping these lines for a three- minute service of cars has been as follows:--
In considering the results of working these lines, it is necessary
that the following be borne in mind:--
(a) The Stockbridge route has only been at work since February last, and the full half-year's receipts have not been obtained on that line.
(b) Expenses inherent to the inauguration of a new line have been charged against revenue.
(c) On the one line the district is only thickly populated over one-half of the route.
(d) The fares charged are less than the rate of one penny per mile.
(e) The speed of cars at present is limited to six miles per hour.
(f) No tramways are allowed to run in Edinburgh on Sundays.
(g) The percentage for administration on a small line is always high, and in this case especially so. The author, therefore, in giving the actual results, also shows reductions on general charges as they would be if the lines worked in conjunction with a larger company.
The reductions under general charges reduce the working expenses to 2902l., which would be at the rate of 5>4 per cent., instead of 64 per cent. of the gross receipts. This result must be compared with 77, the average working percentage with horses over easy roads. If it be remembered that the routes in question are not yet thickly populated, it can easily be seen that the percentage may be far below 50.
The author believes that it is quite impossible for any vehicular
traffic usually making use of the streets to be injuriously affected by
the construction adopted on these lines, and that most of the conditions
urban authorities would insist on have been embodied may be seen from
the following :--
1. The slot in road is narrow, and not as to interfere with vehicular traffic.
2. The amount of metal presented in the surfaces of rails forming the slots is small, and yet strong enough to resist lateral and vertical strains.
3. The slot rails are supported by non-yielding metals, to prevent the slightest possible closing of slot under heavy traffic or atmospherical changes.
4. The pulleys are specially designed to make the noise due to the travel of the cable over them almost imperceptible, and they do not require much attention.
5. The hatches for obtaining access to the pulleys are small.
6. The whole of the driving gear is duplicated, to minimise risks of stoppages.
7. The form of construction is one admitting of rapid laying in the road.
8. The construction is shallow, so as not to interfere more than possible with existing pipes.
9. The average speed of cars is, under the circumstances, faster, and service more frequent, than it could be with horses.
The author desires to take this opportunity of publicly thanking Messrs. Dick, Kerr, & Co., Limited, of London and Kilmarnock, for the very thorough and unselfish manner in which they have carried out the whole of the work of constructing the tramways and machinery.
In concluding, it may be well to draw the attention of members
to the many mechanical motors which have been tried from time
to time for hauling cars, with more or less mechanical and financial
1. Steam locomotives.
2. Steam storage.
3. Gas engines.
4. Ammonia engines.
5. Pneumatic engines.
6. Compressed air stored in receivers on cars.
7. Compressed air supplied in pipes from a main station.
8. Cable system.
9. Electricity conveyed to motor cars from a main station.
10. Electricity generated at a main station, and conveyed through wires placed over the tramway tracks.
11. Electricity conveyed through conductors in tubes under the tracks.
12. Electricity stored on cars.
Only two of these, which have stood the test of time so necessary to properly ascertain motor depreciation, have been able to survive. They are the steam locomotive and the cable system.
The title of this paper, and the time available for its reading and discussion, will not admit of any special reference to motors which may be considered to be taking their trials as competitors for future street haulage ; but the author respectfully submits that, during the last seventeen years, the cable system has firmly established itself as a reliable and efficient caterer to the public requirements, under fairly varied conditions. The financial results have also been so extremely satisfactory as almost to demand the attention of urban and tramway authorities.
The PRESIDENT : Before opening the discussion, gentlemen, I may be permitted to mention a little difficulty in connection with the papers. It would be well if authors of papers could let our secretary have them a little earlier, in order that they might be printed and circulated amongst members. Thus, the time taken up in reading them would be saved, and a proper discussion of the papers could take place. It would be impossible in the little time left at our disposal to properly discuss the papers which we have heard this morning. In opening the discussion, I beg to propose a vote of thanks to the authors of the two papers -- Mr. Cooper, Burgh Engineer of Edinburgh, and Mr. Colam, of the Northern Tramway Company. Speaking of Mr. Cooper's paper first ...
Turning now from this paper, which I should like to still speak about, to Mr. Colam's paper, I think in this case we are deeply indebted to Mr. Colam. Here is an engineer who comes forward with a paper giving us the whole facts in connection with the work which he has been associated with -- keeping nothing back from us, and telling us all that he has to tell; and I think it speaks well for any engineer who will come forward gratuitously, and will tell his brother engineers how he has made successful working tramways, or any work in which he has been engaged. There are one or two points on which I should like a little further illustration. He says there is no reason why cables may not be adapted for working a complete system of tramways, requiring cars to pass over varying routes. Perhaps in his reply he would make that a little clearer. I do not quite understand the analogy from what he said before. Mr. Colam mentions the saving in Australia between the horse lines and cable lines. I should be glad if he has any information that he could lay before us as to whether any comparative returns have been made in England in the same way. Of course, as we know, the success apparently of cable lines depends to a great extent upon the continuous amount of traffic and the life of the cables. I am sorry the time will prevent me from making any further remarks, and I have the greatest pleasure in proposing the vote of thanks that I began my remarks with.
Mr. MEADE : Mr. President, I have much pleasure in seconding the vote of thanks to Mr. Cooper and Mr. Colam for their very excellent papers. Mr. Cooper's paper ...
Returning to Mr. Colam's also very excellent paper, he gives us an immense lot of very useful information, and I hope we will see the illustrations which accompany the paper printed in the Minutes of the Association. It is most useful to have these, and I am sure they will be of great use to municipal engineers who may be thinking of adopting the cable system. I believe I was the first municipal engineer who had to report to his authority upon the cable system, that was in 1882 or 1883, so that cables in this country are quite modern. The cable line at Highgate was, I believe, the first that was constructed in Europe. Now that line, as at first intended, was such that I felt bound to object to many things which the American engineers wished to put down in our streets; they would not at all suit the traffic or the convenience of persons in the country using the roads. Those plans were very much modified, but finally were withdrawn, and a very much better set of plans were afterwards adopted. But coming to the North -- to Edinburgh -- I was very agreeably surprised to find that most of the difficulties in our system at Highgate, in fact nearly all of them, have been obviated. We find here that the area of iron in the road surface -- I am now speaking from a surveyor's point of view -- has been very much reduced. The width of the slot has also been reduced. Now, although that has been reduced in this city, and I believe at Birmingham and other cities, I may say that we have never had an accident or the slightest complaint from the slot at Highgate, which is wider than it is here or at Birmingham. I very much feared at first that we would have difficulties with the slot, but I find it has stood admirably. I may say that the line at Highgate, so far as construction and the quality of materials are concerned, could not have been better. Another point in the Highgate line is the pulleys ; the arrangement of pulleys there is such that if they do not get very close attention they cause noise, and their continual buzzing is a great nuisance to persons living in the line of route, although it may not be observed by passers-by. In Edinburgh I scarcely notice any noise at all; even when listening over the pulleys you can scarcely hear anything. The system of lubricating the pulleys here is very much better than at Highgate, and, I am sure, Mr. Colam will be able to tell us, takes much less labour. With regard to Highgate financially, I have not the slightest doubt that the line would be a success if we could only get the traffic on week days that we get on Sundays. In Highgate we are just reversed to what they are in Edinburgh. In Edinburgh they get their traffic on week days. In Highgate I think five-sixths of the traffic is carried on Sunday, and with the same staff, the same number of cars, and I have no doubt with the same expense for fuel and engine power. So that if we had that traffic it would be a financial success.
Mr. PRITCHARD: I, first of all, must support the proposition that has been made in the vote of thanks that is carried to Mr. Cooper and Mr. Colam for the very instructive and, I consider, very ably prepared papers. I regret I was not sufficiently long in the room to hear the first paper read, but I feel satisfied that from what little I did hear that the whole paper may be taken as a good one, and I hope in the future the suggestion of our worthy president will be adopted, that the papers should be handed in in time for them to be perused before the discussion ; especially when papers are submitted of such importance as that bearing on the matter of sewage. It will give us a proper opportunity to fully appreciate an able paper such as the one we have had. There are two points in that paper to which I would like to ask your attention ...
I am, I think, now rather in sympathy with my friend Mr. Colam. I read in the Scotsman yesterday, from a special correspondent, something about one of the oldest Town Councillors of the city devoting his time in London to discovering the best modes of paving ; and I notice there some remarkable information -- information which I certainly was not in possession of before. I rather hesitate now to accept it, seeing it has to be verified. But I would like to point out this. Wood paving in its best form is a luxurious paving, but it has not the life that the writer of the Scotsman tells us it has. But I would certainly warn the authorities against attempting to pave the cable car lines with wood. We have had cases where, as Mr. Meade very carefully describes, there was a tendency to close. I have taken great interest for several years in connection with tramways, and in conjunction with my colleague, Mr. Kincaid, M. Inst. C.E., have had to advise for a large installation in Birmingham. I visited every city in America, excepting one, where there was a cable system laid, endeavouring to escape their mistakes, and if possible to adopt the very best system. We have done our best. All I can say, in reference to the Edinburgh roads -- and I have had an opportunity of seeing them from the first very frequently -- is that they are really, for the money expended, very good roads. They are lighter than the Birmingham roads, and so far they have shown they are very well constructed. Mr. Colam has referred to me on two points which I would like, without taking up much time, to make allusion to. He refers to the hilly districts as being practically reduced to level plains. That is so. There is no known power of traction so economical as that of rope haulage. I have had experience of cable and steam, and now of electric, having just completed six miles of electric road driven by accumulators. He says the hilly districts are reduced to level roads. It has been said " You may work your hilly districts, because you compensate your roads, but if you get on to a level district you can do nothing." I saw in Chicago about twenty miles of road. That is a perfectly level plain. I afterwards stated, on my return to England, that I believed I should be able to haul, all expenses included, at about 5 1/2d. per mile. That statement was simply ridiculed, but Mr. Colam has pointed this morning to the Birmingham road. I assure you it is coming very near it. In the Birmingham Company's published accounts for twelve months they give the cost per mile, inclusive of every expenditure, at 6 1/10d. There is no other system where you can get that. The President referred to the comparison as to the Melbourne saving, and the payment of a big dividend. I also would have liked to have put a question to Mr. Colam upon that point. We know it is not the matter of dividend paid, but we want to know the basis upon which the dividend is declared. In Birmingham, for instance, the dividend is a very small one, but the money supplied by the cable route for the last twelve months gives 13,500l. available for dividend from three miles of route. As the cost of working cable tramways is very much the result of construction, further information is desirable. I do not know whether it is asking too much, or whether we ought to expect that, but if so, I should like Mr. Colam to give us the number of car miles run, with the expenditure; or, if he prefers it, the cost per mile for haulage, or the total cost per mile of working expenses ; also the receipts per mile. Much depends on the clear statement of the points I have mentioned, when a comparison is made, as in the case of Birmingham, where during the last twelve months the cost of haulage has been very low, only 2.55 pence (slightly over 2 1/2d.) per car mile. In Edinburgh the population is not so dense as in Birmingham, but it would be interesting to know what the cost of traction or haulage per mile is. There are many other points I would like to have alluded to, and I think, in justice to Mr. Colam, I must note one. and that is the gripper. There is no doubt it is an exceptionally clever invention. I think the company are very fortunate in having so able a gentleman in charge of so important an undertaking as the Edinburgh Cable Tramway ...
The PRESIDENT : I am afraid I shall have to close this discussion. If any other members desire to ask questions, if they would put them in writing, I am sure that Mr. Cooper and Mr. Colam would be very happy to answer them, so that we may have them in the Minutes of the Proceedings of the Association. I will now put the vote of thanks to Mr. Cooper and Mr. Colam.
The vote was carried with applause.
Mr. COOPER : I came before you with much diffidence, and threw myself upon your generosity; I knew there was plenty of it. In regard to the way in which I treated the secretary in not sending him my paper beforehand, it never occurred to me that it would be printed and circulated. But Burgh Engineers here all know how one's time is absolutely frittered away by small details, and the preparation of a paper, unless it is in the hands of our more capable and literary brethren, is not altogether a joke ...
Mr. COLAM : I have to thank you, Mr. President and Gentlemen, for the kind way in which you have received this paper. I am sure of this -- it has given me a great deal more pleasure to bring it before you than it can possibly have given you to receive it. It has been my study for a very long tune, and it has also been my particular wish to concentrate my knowledge on the subject in a paper before such a body as yourselves, who are really the people we have to deal with when it comes to the point. I would also like to reply to the President to make matters a little more explicit on the points on which he wishes information. As to what I meant when I said we had demonstrated in Edinburgh that systems of tramways in various parts of the city could be worked into one system by interchange -- what I meant was this. Assuming you have a tramway being worked in the west end of the city by an engine-room which is in the west end, and an engine-room the power of which can only be carried to a certain distance, say to the centre of the city or any other part, you can also have another one working the east end of the city, extending the cable up to the very point where the other one from the west end leaves off. I have demonstrated in Edinburgh that this can be done, because I have one system at work in one portion of the city and I have another system in another, and at the point where these two join there is a connection by an auxiliary cable, although they meet, as it were, round a corner. With regard to the other remark of the President, about the comparative results from horses and cables, I think I referred to that in my paper. I pointed out the results in Birmingham from the cable cars and the horse cars. It is not necessary for me to say that in taking these figures you must have a local knowledge of the place. You must know whether the horses are working under the same conditions as the cable cars. With regard to Mr. Meade's remarks, I am much obliged to him for what he has said. He has had perhaps more opportunities than any engineer present of going into my plans. He knows the construction here as compared with Highgate, and as compared with what was originally proposed by the American engineers when they first came. I shall have great pleasure in adopting the suggestion thrown out by Mr. Meade in providing the secretary with the blocks which are contained in my paper for the purpose of your 'Proceedings.' With regard to Mr. Pritchard's remarks, he says he has had some experience of the closing of the slots. I am very pleased to say we have not had that experience. But then our local authorities have not insisted upon wood. At the same time it has, I think, been demonstrated pretty clearly that we are getting woods now from Australia which may meet this difficulty.
Mr. PRITCHARD : Australian lines have closed.
Mr. COLAM : But there is a reason for that. I think that the form of construction of the slot rail is wrong. It is one that lends itself to closing, and with all due deference to Mr. Pritchard the rail that is introduced into Birmingham also lends itself to closing, because it leans over on the side, out of the perpendicular, and any pressure which is being brought to bear laterally only tends to turn the rail about a point 6 inches below the surface of the road. With regard to the Chicago lines, I may say I have a letter from the president of the company, in which he says that he now finds the working expenses per car mile run on the cables to be 9 1/2 cents, compared with 23 cents by horse previously. With regard to Melbourne I must say I never attempted to give any comparative information upon it, because I thought it was rather infringing upon the limit of my paper. But with all due deference to Mr. Pritchard I do not think it is of any use giving you information as to the cost per mile run. It is information that is in a way useful, but it is very misleading to those who are not possessed of a special knowledge as to tramway work. The cost of running per car mile depends of course entirely upon the facilities for working. In Edinburgh, I think, we are working at 54 per cent. of our gross receipts, far below any other tramway in the country excepting Birmingham. Our expenses per car mile come out high, but at the same time we should be able to pay a dividend where companies working at the lower cost per mile would not; therefore I think it is misleading. You can give the cost of haulage as separate, and then you can give the cost per car mile under certain conditions. Therefore I contend that the hackneyed expression "What is the cost of running per car mile ?" is altogether misleading. I do not think I have given the number of cable car miles. I have simply referred to the number of miles laid, and some few interesting points. If I had gone into the Melbourne system, there is no reason why I should not have gone into the Brooklyn, the Chicago and the San Francisco systems, which are doing very well. Therefore I think it was well to confine my remarks to such as I gave in the paper. I again thank you very much.
On Thursday the 26th, after discussing the papers, the members were taken over the Cable Tramway lines, and visited the machinery depot. &c. They then proceeded to the City Chambers, where, in the absence of the Lord Provost, the Deputy Lord Provost and members of the Corporation received and entertained the party to luncheon. A visit was then paid to the Exhibition, where the members were recieved by the Executive Committee, and afterwards inspected the exhibits. In the evening the members were entertained to dinner by the Cable Tramways Corporation.
On Friday the 27th, a visit was paid to the Forth Bridge. The party was met at the Queensferry Station, north of the bridge, and conducted over the bridge on foot. They then embarked on a steamer, passed under the bridge and around the piers, back to the south side, and returned to Edinburgh by coach.
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