Cassier's Magazine: Engineering Illustrated
volume 17, November, 1899- April, 1900.
AN ELECTRIC TRAMWAY IN THE BRITISH WEST INDIES
By H. Holgate
By H. Holgate
PROBABLY one of the most unlikely places in the world to look for anything very modern would be the British West Indies, and yet a visit to Kingston, the chief city of Jamaica, will convince one that the tide of progress has reached this old colony, and the existence of a new and first-class tramway system there shows that, even if some of the natives have no faith in the country's future prosperity, others have. The Jamaican, however, cannot forget the time, now past forever, when rum and sugar made riches very quickly, and these products, through foreign competition, aided by the chemist, now failing to yield as large profits as formerly, he has, at least for a time, been discouraged from developing the other resources of his wonderful
island.
This was the condition when a Canadian syndicate, in 1897, bought the properties and rights of the Jamaica Street Car Company, and contracted to build and operate in its stead a system of electric cars. The Jamaica Street Car Company was operating about twelve miles of single-track tramways with mules, and though the business was profitable to the owners, the citizens of Kingston demanded better service than could be given by mule traction. The tramway people were unwilling to put more capital into the business, and as the government were on the eve of carrying out extensive street improvements in Kingston, whereby the street car company would be obliged to renew their tracks, the latter took the opportunity of selling the property to those who were willing to carry out the improvements.
A license was granted by the island government to the West India Electric Company to build electric tramways within the area described in the license, which embraces the whole of Kingston and a portion of the parish of St. Andrew, the population embraced in this area being about 65,000 inhabitants. The work of the new company embraced twenty-five miles of tracks, or double the mileage of the old company, and the approved system of traction was the overhead trolley. The time for installing a new tramway system in Kingston was opportune. The streets were all in a completely worn-out condition, and during the rainy seasons the city presented a sorry spectacle. Active preparations were made by the government to reconstruct the principal streets, and the tramway tracks were laid on these ahead of the work of reconstructing the roadways. The tramway cornpany was responsible for the building of the streets between its rails and tracks, and for 18 inches beyond the outer rails, so that in a street 32 feet wide, the company had to do most of the street construction. The surface of the roadways in the city was paved with brick, laid on a 4-inch concrete bed.
Now that the reconstruction of the principal streets of Kingston has been accomplished, the visitor of a few years ago will hardly recognise, in the clean brick streets with cast iron box drains, the old city, with its mud roads and clogged-up, filthy surface drains. The benefit produced by the change made is a most valuable one sanitarily, and no doubt the slight visitation of yellow fever in 1897 stimulated the government to prompt action; the authorities have done their work on broad plans, and are doing it well, and yellow fever will probably never trouble Kingston again.
Within the city where brick paving was adopted the rails laid were of girder section, and weighed 92 pounds per yard ; on streets where brick paving was not adopted, but where macadam was used, the track consisted of 6-inch T-rails weighing 62 pounds per yard. The tracks throughout were laid in concrete stringers on steel ties weighing 10 pounds per yard. The overhead construction is all carried by steel poles, set in concrete, and conforms to the best modern practice.
The equipment consists of twenty motor cars of the open, summer type, carrying 9 benches; six market cars, carrying 32 people and their baskets of produce; and two sprinkling tanks of 2000 gallons capacity each. The company has agreed to carry market people in special market cars at 75 per cent, of the regular fare. These cars are used as trailers; owing to the prevalence of dust on the streets, the company also runs its sprinkling cars, using fresh water for sprinkling purposes, the use of salt water being avoided for electrical reasons.
With the improved facilities for travelling, the number of passengers has increased to such an extent that additional rolling stock has already been ordered. Of course, the bulk of the passengers carried is black, and a large proportion of these are from the country, principally women who walk in with head loads of fruit, sometimes twenty miles to the tramway terminus, where they sleep over night in the "Rest House" provided by the company at a nominal charge, and complete their journey to Kingston market in the morning by electric car.
The system is divided into three districts for fares; one comprises the lines in the city; one, those north; and one, the lines east of the city. In each district a separate collection of fares is made. The class distinction has had to be observed, and the two front benches of the motor cars are "reserved," and the fare of threepence per district is charged, whereas the ordinary fare in other parts of the cars is twopence per district.
The work of construction was commenced in Kingston in June, 1898, and the whole system was in full operation by April 1, 1899, including the power plant. The high cost of coal in Jamaica rendered the use of water power very desirable, and after making a study of the various streams within reasonable distance of Kingston, it was decided to utilise the Rio Cobre for the purpose of developing the necessary power. The river afforded a fall of fifty feet from the mouth of the railway tunnel at Bog Walk to a practicable power house site, and a dam and intake were built opposite the tunnel; the water was conducted from the intake 6200 feet down the river bank in a steel pipe, 96 inches in diameter, to the power house.
This conduit was built of one-quarter-inch medium steel plates, delivered on the ground, rolled to diameter, and punched; native labour was employed to assemble and rivet the plates. Wherever possible the pipe was embedded in the solid rock or earth; but in some places this was impossible, and the pipes had to be supported by concrete piers, three feet wide, placed eleven feet from centre to centre.
The variable load, produced by the operating of a comparatively small number of electric cars, exacted conditions of governing not usually called for, and the length of the conduit, together with its unavoidably irregular profile, added to the difficulties of governing. A steel tank, four feet in diameter, rising above the level of headwater, was erected close to the power house, and served as a relief to the water in the sudden cutting-off of load. This was found not to give sufficiently quick action. Two other tanks, each eight feet in diameter, were then erected on the pipe, one at the summit, and one between it and the power house, and these produced the results expected, overcoming the difficulties of governing the speed, and also relieving the pipe of the "breathing" action so continually going on under the constantly varying load. Had the load been steady, no difficulty would have been experienced, and the more nearly approaching a constant load, the less difficulty will be experienced in operating long pipe lines in connection with turbines. The use of heavy fly-wheels on both exciters and generators under these conditions is very desirable, as has been shown by the operation of this plant.
The power house is of most substantial construction, as it must be, situated practically in the river, and subject to the rush of water caused by the sudden freshets common to all tropical streams. The frame is of steel, and the walls are of concrete; the floor also is of concrete, carried on a steel floor system. The foundations extend to the rock, sixteen feet below the river bed.
The installation at the power house consists of two pair of 21 -inch horizontal turbines, direct coupled to two three-phase, 12-pole generators of the stationary field type, operating at 550 volts, and making 400 revolutions per minute. They are of 300 K.W. nominal capacity, and were made by the General Electric Company, of New York. Room has been left for a third unit. There are two exciters, each capable of exciting three generators of the above type, and each run by a separate wheel. The generators each feed three step-up transformers, which are air-cooled. All low-tension connections are made in the air duct below the transformers, and all high-tension connections are made overhead and are led directly out of the building through an opening framed in the structure; they are carried around and again into the building to the back of the switchboard.
The switchboard consists of eight marble panels. The switches for breaking the high-tension current are each on a separate panel and are of the triple-pole, double-throw, oil-break form, only the handle appearing in front of the board. The two transmission lines are paralleled by a triple-pole, single-throw, oil-break switch, on a separate panel. No high-tension connections are made to the front of the switchboard. The usual switching apparatus occupies the other panels, and the whole is a most complete arrangement, made with a view to the highest flexibility.
Every attention has been given to the avoidance of high-tension wires in the building, and only low-tension wires are carried in the ducts in the floor. The ratio of the step-up transformers is 1 to 26, the high-tension line voltage being 14,000. The transmission line is in duplicate. With the switchboard arrangement adopted either generator may work on either line, or either generator on both lines, or both generators on either line.
The transmission line is 21 miles long, and follows the public highway. The poles are of steel, tapered from 3½ inches to 4½ inches, and are 31 feet long; at angles, however, heavier poles are used. All poles are 5 feet in the ground and embedded in concrete. They are spaced 132 feet apart. The wires are six in number and are No. 6 gauge, of soft drawn copper, tested to 800 pounds tensile strain, without reduction in cross-section. They are carried on double-petticoat porcelain insulators, tied with No. 15 soft copper wire, and carried on locust pins on 4-inch by 6-inch pine cross-arms, secured by U bolts to the steel pole. The length of the line is divided equally, and the wires are transposed at each point one-third of a turn, so as to form a spiral of two complete turns in the total length. A telephone line is strung on the same cross-arms, its wires being transposed at every fifth pole; it is made of No. 15 phosphor-bronze wire strung on glass insulators, and is nearly free from induction. A system of gong signals, worked from the 550-volt circuit, is used between stations, which remains cut in, except when it is required to use the telephone.
In order to construct this line, and to render it safe for operation, an immense amount of tree cutting had to be done, and as the tree growth is very rapid, constant trimming is necessary. A source of slight trouble arises from the "John Crows" or buzzards. These birds, after a shower, are in the habit of alighting on a cross-arm, and spreading their wings to dry, thus often coming to grief from the momentary short circuit. No serious trouble has been so caused, nor is there likely to be any, though thirteen dead birds were found in one day. Insects, too, have the bad habit of building nests in the insulators, spinning webs and shortening up the insulating surface. This, coupled with the fact that fine dust gradually gathers under the petticoats and adheres to the porcelain sides, and that the cracks in locust pins and pitch-pine cross-arms harbour dampness, render the insulation of the line a matter of great concern in times of heavy rain, and constant watchfulness is of great importance. For this purpose a patrol is organised to examine the line daily.
The step-down transformers, rotatory converters with all necessary switchboards and apparatus are placed in a brick building on the company's property in Kingston. The building is of steel construction, built-in brick walls, with steel frame roof, and clear story provided with iron louvre blades. A 5-ton travelling crane traverses the whole of the interior. There are six air-cooled step-down transformers reducing the current to 350 volts. The rotary converter units, at present two in number, are 6-pole machines of 200 K.W. capacity each. The system is complete and has been working with most satisfactory results for over six months. The wiring of the transforming station has been done with a view to having none but low-tension wires in the floor ducts. In regard to the labour used in building this work, some particulars are worth mentioning. The company brought ten white men to Jamaica to supervise the whole of the work of construction. The work was entirely new to the Jamaica negro, and he had to be taught. At first he would persist in his easy-going ways, coming to work on Tuesday and quitting Friday night, but when he found that the company kept on only good, steady hands, he fell into line and worked cheerfully the whole week.
All of the work was done by negroes, — many women being employed, — tracks laid, roads built, cars erected, wires strung, machinery installed, car house and power house built, and also the pipe line and dam. The negro is a good imitator, and when carefully shown how to do his work, will do it that way. In driving the rivets for the steel pipe it was found that just two-thirds of the day' s work were done in the first half of the day, the reason being that the power of endurance was not equal to the demands of the work, and this is no doubt attributable to the quality of food used, for a baked bread fruit, and perhaps a scrap of salt fish and a mango or two, comprise the regular meal of most of the men.
The cost of labour per unit of quantity of work done was about the same as it would be in Canada, and though the daily wages for labour were less, the amount of work accomplished was correspondingly less per man, as compared with the work done by a Canadian workman. The cost of supervision was considerably more than with white labour. The Jamaica negro is a peaceable fellow, works well under strict and kind direction, and the company's experience is that he is by no means an unsatisfactory man. The electric cars are all manned with black men, who have been trained carefully, and the extra trouble taken in their training is amply repaying the company. It has resulted in obtaining a class of men who, for general intelligence and carefulness, are equal to any men in corresponding positions elsewhere. Had the native not been such a satisfactory labourer, the company's work could not have been done in so short a time. The entire work occupied only nine months from the first breaking up of the roads to the running of electric cars.
island.
This was the condition when a Canadian syndicate, in 1897, bought the properties and rights of the Jamaica Street Car Company, and contracted to build and operate in its stead a system of electric cars. The Jamaica Street Car Company was operating about twelve miles of single-track tramways with mules, and though the business was profitable to the owners, the citizens of Kingston demanded better service than could be given by mule traction. The tramway people were unwilling to put more capital into the business, and as the government were on the eve of carrying out extensive street improvements in Kingston, whereby the street car company would be obliged to renew their tracks, the latter took the opportunity of selling the property to those who were willing to carry out the improvements.
A license was granted by the island government to the West India Electric Company to build electric tramways within the area described in the license, which embraces the whole of Kingston and a portion of the parish of St. Andrew, the population embraced in this area being about 65,000 inhabitants. The work of the new company embraced twenty-five miles of tracks, or double the mileage of the old company, and the approved system of traction was the overhead trolley. The time for installing a new tramway system in Kingston was opportune. The streets were all in a completely worn-out condition, and during the rainy seasons the city presented a sorry spectacle. Active preparations were made by the government to reconstruct the principal streets, and the tramway tracks were laid on these ahead of the work of reconstructing the roadways. The tramway cornpany was responsible for the building of the streets between its rails and tracks, and for 18 inches beyond the outer rails, so that in a street 32 feet wide, the company had to do most of the street construction. The surface of the roadways in the city was paved with brick, laid on a 4-inch concrete bed.
Now that the reconstruction of the principal streets of Kingston has been accomplished, the visitor of a few years ago will hardly recognise, in the clean brick streets with cast iron box drains, the old city, with its mud roads and clogged-up, filthy surface drains. The benefit produced by the change made is a most valuable one sanitarily, and no doubt the slight visitation of yellow fever in 1897 stimulated the government to prompt action; the authorities have done their work on broad plans, and are doing it well, and yellow fever will probably never trouble Kingston again.
Within the city where brick paving was adopted the rails laid were of girder section, and weighed 92 pounds per yard ; on streets where brick paving was not adopted, but where macadam was used, the track consisted of 6-inch T-rails weighing 62 pounds per yard. The tracks throughout were laid in concrete stringers on steel ties weighing 10 pounds per yard. The overhead construction is all carried by steel poles, set in concrete, and conforms to the best modern practice.
The equipment consists of twenty motor cars of the open, summer type, carrying 9 benches; six market cars, carrying 32 people and their baskets of produce; and two sprinkling tanks of 2000 gallons capacity each. The company has agreed to carry market people in special market cars at 75 per cent, of the regular fare. These cars are used as trailers; owing to the prevalence of dust on the streets, the company also runs its sprinkling cars, using fresh water for sprinkling purposes, the use of salt water being avoided for electrical reasons.
With the improved facilities for travelling, the number of passengers has increased to such an extent that additional rolling stock has already been ordered. Of course, the bulk of the passengers carried is black, and a large proportion of these are from the country, principally women who walk in with head loads of fruit, sometimes twenty miles to the tramway terminus, where they sleep over night in the "Rest House" provided by the company at a nominal charge, and complete their journey to Kingston market in the morning by electric car.
The system is divided into three districts for fares; one comprises the lines in the city; one, those north; and one, the lines east of the city. In each district a separate collection of fares is made. The class distinction has had to be observed, and the two front benches of the motor cars are "reserved," and the fare of threepence per district is charged, whereas the ordinary fare in other parts of the cars is twopence per district.
The work of construction was commenced in Kingston in June, 1898, and the whole system was in full operation by April 1, 1899, including the power plant. The high cost of coal in Jamaica rendered the use of water power very desirable, and after making a study of the various streams within reasonable distance of Kingston, it was decided to utilise the Rio Cobre for the purpose of developing the necessary power. The river afforded a fall of fifty feet from the mouth of the railway tunnel at Bog Walk to a practicable power house site, and a dam and intake were built opposite the tunnel; the water was conducted from the intake 6200 feet down the river bank in a steel pipe, 96 inches in diameter, to the power house.
This conduit was built of one-quarter-inch medium steel plates, delivered on the ground, rolled to diameter, and punched; native labour was employed to assemble and rivet the plates. Wherever possible the pipe was embedded in the solid rock or earth; but in some places this was impossible, and the pipes had to be supported by concrete piers, three feet wide, placed eleven feet from centre to centre.
The variable load, produced by the operating of a comparatively small number of electric cars, exacted conditions of governing not usually called for, and the length of the conduit, together with its unavoidably irregular profile, added to the difficulties of governing. A steel tank, four feet in diameter, rising above the level of headwater, was erected close to the power house, and served as a relief to the water in the sudden cutting-off of load. This was found not to give sufficiently quick action. Two other tanks, each eight feet in diameter, were then erected on the pipe, one at the summit, and one between it and the power house, and these produced the results expected, overcoming the difficulties of governing the speed, and also relieving the pipe of the "breathing" action so continually going on under the constantly varying load. Had the load been steady, no difficulty would have been experienced, and the more nearly approaching a constant load, the less difficulty will be experienced in operating long pipe lines in connection with turbines. The use of heavy fly-wheels on both exciters and generators under these conditions is very desirable, as has been shown by the operation of this plant.
The power house is of most substantial construction, as it must be, situated practically in the river, and subject to the rush of water caused by the sudden freshets common to all tropical streams. The frame is of steel, and the walls are of concrete; the floor also is of concrete, carried on a steel floor system. The foundations extend to the rock, sixteen feet below the river bed.
The installation at the power house consists of two pair of 21 -inch horizontal turbines, direct coupled to two three-phase, 12-pole generators of the stationary field type, operating at 550 volts, and making 400 revolutions per minute. They are of 300 K.W. nominal capacity, and were made by the General Electric Company, of New York. Room has been left for a third unit. There are two exciters, each capable of exciting three generators of the above type, and each run by a separate wheel. The generators each feed three step-up transformers, which are air-cooled. All low-tension connections are made in the air duct below the transformers, and all high-tension connections are made overhead and are led directly out of the building through an opening framed in the structure; they are carried around and again into the building to the back of the switchboard.
The switchboard consists of eight marble panels. The switches for breaking the high-tension current are each on a separate panel and are of the triple-pole, double-throw, oil-break form, only the handle appearing in front of the board. The two transmission lines are paralleled by a triple-pole, single-throw, oil-break switch, on a separate panel. No high-tension connections are made to the front of the switchboard. The usual switching apparatus occupies the other panels, and the whole is a most complete arrangement, made with a view to the highest flexibility.
Every attention has been given to the avoidance of high-tension wires in the building, and only low-tension wires are carried in the ducts in the floor. The ratio of the step-up transformers is 1 to 26, the high-tension line voltage being 14,000. The transmission line is in duplicate. With the switchboard arrangement adopted either generator may work on either line, or either generator on both lines, or both generators on either line.
The transmission line is 21 miles long, and follows the public highway. The poles are of steel, tapered from 3½ inches to 4½ inches, and are 31 feet long; at angles, however, heavier poles are used. All poles are 5 feet in the ground and embedded in concrete. They are spaced 132 feet apart. The wires are six in number and are No. 6 gauge, of soft drawn copper, tested to 800 pounds tensile strain, without reduction in cross-section. They are carried on double-petticoat porcelain insulators, tied with No. 15 soft copper wire, and carried on locust pins on 4-inch by 6-inch pine cross-arms, secured by U bolts to the steel pole. The length of the line is divided equally, and the wires are transposed at each point one-third of a turn, so as to form a spiral of two complete turns in the total length. A telephone line is strung on the same cross-arms, its wires being transposed at every fifth pole; it is made of No. 15 phosphor-bronze wire strung on glass insulators, and is nearly free from induction. A system of gong signals, worked from the 550-volt circuit, is used between stations, which remains cut in, except when it is required to use the telephone.
In order to construct this line, and to render it safe for operation, an immense amount of tree cutting had to be done, and as the tree growth is very rapid, constant trimming is necessary. A source of slight trouble arises from the "John Crows" or buzzards. These birds, after a shower, are in the habit of alighting on a cross-arm, and spreading their wings to dry, thus often coming to grief from the momentary short circuit. No serious trouble has been so caused, nor is there likely to be any, though thirteen dead birds were found in one day. Insects, too, have the bad habit of building nests in the insulators, spinning webs and shortening up the insulating surface. This, coupled with the fact that fine dust gradually gathers under the petticoats and adheres to the porcelain sides, and that the cracks in locust pins and pitch-pine cross-arms harbour dampness, render the insulation of the line a matter of great concern in times of heavy rain, and constant watchfulness is of great importance. For this purpose a patrol is organised to examine the line daily.
The step-down transformers, rotatory converters with all necessary switchboards and apparatus are placed in a brick building on the company's property in Kingston. The building is of steel construction, built-in brick walls, with steel frame roof, and clear story provided with iron louvre blades. A 5-ton travelling crane traverses the whole of the interior. There are six air-cooled step-down transformers reducing the current to 350 volts. The rotary converter units, at present two in number, are 6-pole machines of 200 K.W. capacity each. The system is complete and has been working with most satisfactory results for over six months. The wiring of the transforming station has been done with a view to having none but low-tension wires in the floor ducts. In regard to the labour used in building this work, some particulars are worth mentioning. The company brought ten white men to Jamaica to supervise the whole of the work of construction. The work was entirely new to the Jamaica negro, and he had to be taught. At first he would persist in his easy-going ways, coming to work on Tuesday and quitting Friday night, but when he found that the company kept on only good, steady hands, he fell into line and worked cheerfully the whole week.
All of the work was done by negroes, — many women being employed, — tracks laid, roads built, cars erected, wires strung, machinery installed, car house and power house built, and also the pipe line and dam. The negro is a good imitator, and when carefully shown how to do his work, will do it that way. In driving the rivets for the steel pipe it was found that just two-thirds of the day' s work were done in the first half of the day, the reason being that the power of endurance was not equal to the demands of the work, and this is no doubt attributable to the quality of food used, for a baked bread fruit, and perhaps a scrap of salt fish and a mango or two, comprise the regular meal of most of the men.
The cost of labour per unit of quantity of work done was about the same as it would be in Canada, and though the daily wages for labour were less, the amount of work accomplished was correspondingly less per man, as compared with the work done by a Canadian workman. The cost of supervision was considerably more than with white labour. The Jamaica negro is a peaceable fellow, works well under strict and kind direction, and the company's experience is that he is by no means an unsatisfactory man. The electric cars are all manned with black men, who have been trained carefully, and the extra trouble taken in their training is amply repaying the company. It has resulted in obtaining a class of men who, for general intelligence and carefulness, are equal to any men in corresponding positions elsewhere. Had the native not been such a satisfactory labourer, the company's work could not have been done in so short a time. The entire work occupied only nine months from the first breaking up of the roads to the running of electric cars.
[pages 74-82, text only]