The Limmat Valley Electric Road Railway.” by CHARLESSHEIBNER DU RICEEPRELLER, M.A., Ph.D., Assoc

346 PRELLER ON THELIMXAT VALLEY

(Paper No. 3347.) ‘‘ The Limmat Valley Electric Road Railway.” By CHARLESSHEIBNER DU RICEEPRELLER, M.A., Ph.D., Assoc. M. Inst. C.E. THE LimmatValley Road Rail.way, likemany similar light railways, owes its existence to the failure of the main line of the district to afford timely and adequate facilitiesfor the development of local traffic. Runningparallel to the Swiss North-Eastern trunk line from Zurich to Berne and Bile, the line connects five largevillages of theLimmat Valley with the town of Zurich, which has an aggregate population of 160,000, whilst that of the five villages together is 10,000. In the year 1898, after considerable opposition and delay, a concession for a line to carry both passenger- and goods-traffic was granted by the Cantonal and Federal Governments. The special plans, sections and designs of the lineand of the electrical equipment, prepared under theAuthor’s directions, having been approved by the Authorities, anda Company having been formed with the financial co-operation of the Canton of Zurich and of the villageCorporations, the work of construction was commenced in the springof 1900. Description of the Line.-Starting from the town boundary of Zurich, where it joins theCorporation system of electric tramways, the railway runs alongside the public road, passing through the villages of Altstetten, Schlieren andDietikon, with a branch from Schlieren to Engstringen and Weiningen, the total length being 73 miles, Fig. 3. The curves, and also thegradients, are easy; the sharpest of the former are two curvesof 82 feet radius, whilst the steepest gradient is about 1 in 18, on a short section of 275 yards in length, on thebranch line. The railway is constructed as a single line, with eight passing-places, each 55 yards in length, spaced about 1 mile apart. The gauge, like that of the Zurich tramway system, is 1 metre (3 feet 3; inches). The permanent-way is composed of steelrails of Vignoles section, weighing 402 lbs. per lineal yard, resting on iron sleepers 5 feet 3 inches in length and each weighing 22 lbs., there being fourteen sleepers to each rail-length of’ 33 feet 7 inches. The

Downloaded by [ Purdue Univ Lib TSS] on [14/09/16]. Copyright © ICE Publishing, all rights reserved. Papers.] ELECTRIC ROAD BAILWAY. 347 bearing capacity between the points of support is therefore 8 tons, whilst the actual maximum load per wheel is only 3 tons. The permanent-way rests on packing and ballast, 6 feet 6 inches in

width and 1 foot 4 inches in depth, the width of formation outside the public road being 11 feet 6 inches. In the passing-places the permanent-way consists of l’hceuix girder-railsand turnouts

Downloaded by [ Purdue Univ Lib TSS] on [14/09/16]. Copyright © ICE Publishing, all rights reserved. 348 PRELLER ON THE LIXMATVALLEY [Selected weighing 188 lbs. per yard, and on all road-crossings, sharp curves and bridges, double Vignoles rails are laid. On the branch line the railwaycrosses the River Limmat on an iron girder-bridge 82.5 yards in length, the rails being 20 feet above the average level, and 11 -7 feet above the flood-level of the river.The bridge is constructed as acontinuous girder, 7 feet 6 inches in height and 10 feet in width of platform, with three openings of equal length, and for a moving load of 24 tons on eight wheels for motor-cars and on twelve wheelsfor goods-trucks. The railway crosses the Swiss North-Eastern trunk lineon level crossings attwo points, one between Alstettenand Schlieren, where it traverses the old single line from Zurich to Zug at an angle of 37 degrees, and the other atSchlieren, on the branch line, where it intersects the double trunk-line from Zurich to Berne and BBle, and a siding, at an angle of 85 degrees. In both cases the North-Eastern Railway, supported by the FederalGovernment, insisted that its railsshould not be cut at the pointsof intersection, althoughin other countries, wheresuch level crossings are permitted by the authorities, it has been recognised that a groove in the main-line rails, for the passage of the wheel-flanges of the light-railway cars, is an advantage to both lines concerned. The stations and stopping-places number about forty along the whole line,equal to one in every 330 yards. Atthe principal stopping-places, waiting-huts, lighted electrically, are erected for the use of passengers ; at others, rooms in public houses or other suitable buildings are set apart for the purpose. The parcel- and goods-traffic is similarly dealt with. Elect&nl Eput$ment of the Line.-The single contact-line, inch in diameter, is elastically suspended at a height of 21 feet 4 inches aboverail-level, from steelbrackets varying in length up to 10 feet 10 inches, which are fixed to wooden poles. The latter are spaced 27 feet 6 inches to 33 feet apart, are 10 inches in mean thickness and 29 feet 6 inches in height, of which 5 feet 3 inches is underground and imbedded in concrete. The return circuit also consists of a &-inch copper conductor, and is connected every four rail-lengthswith the Chicago bonds of the rail-joints. On the branch line this special return conductor is dispensed with, the electrical bonding being strengthened instead, and the fish-joints and bonds being soldered to the rails with a highly-conductive amalgam. The poles carry, besides the steel brackets,a #rich feeder, and a double-service telephone line which is connected to all the principal stations and stopping-places along the railway, and to the power-station. The line is divided,electrically, into

five separate sections, each of about 13 mile in length, by special cut-outs, and special cut-outappliances are also provided at thelevel crossings of theNorth-Eastern Railway, wherethe currentis switched on only at fixed intervalswhen the trunk line is signalled.clear, andthe electric railway-cars can pass. Considerable extra expense was caused by theFederal Govern- ment requiring all the overhead suburban, interurban, telephone, and other electrical lines running parallel to the railway, to be removed and placed underground,or re-erected at a certain distance from therailway contact-line, whilethe numerous overhead electric-lighting systems in the variouslocalities had to be strengthened and altered. Power-Station and High-Tension Transmission.-The power-station is situated at Schlieren, almost equi-distant from the three ter- minal points of the railway, with which isit connected by a loop- line 220 yards in length. It comprises machine-room, car-shed, repair-shop, central offices, rooms for the staff, store-yard, and sidings, and covers a superficial area of about 4,780 square yards. The car-shed is constructed for fifteen motor-cars, whilst outside sidings are provided for goods-trucks and for the remainder of the rolling stock. The machine-room contains, for the present, two sets of 100-kilowatt motor-generators, built Ey Messrs. Brown, Boveri and Company, with reserve space for a. third set. Each set is composed of a three-phase, 2,000-volt, 50-cycle motor, driving on the sameshaft acontinuous-current 650-volt to 600-volt four-pole dynamo, and making 500 revolutions per minute. The motors are connected by their own switchboard with the high-tension transmission leading to the Zurich Corporation central station, while the generators are similarly connected with the five sections of the line. To the three-phasetransmission is also connected a 3-kilowatt transformer, transforming down from 2,000 roltsto 200 volts, for lighting thedepBt with about fiftylamps, and, during the daytime, for driving a %HP. motor in the repair-shop. The high-tension transmission from the Zurich central station to the power-station of the railway at Schlieren is about 32 miles inlength, and is composedof three $-inch conductors, which, within the town boundary, i.e., for the first mile, are laid underground, and for the remainder are carried overhead on wooden poles about 55 yards apart, except at the overheadcrossing of the North-Eastern Railway, where the unprotected high-tension conductors are passed on both sidesover iron towers. Atthe central station the transmission-lineis connected to the 1,000-HP. 2,000-volt 50-cycle three-phase steam alternators, which also feed the motor-generator station of the Corporation Tramways.

Downloaded by [ Purdue Univ Lib TSS] on [14/09/16]. Copyright © ICE Publishing, all rights reserved. 3.50 PRELLER ON THE LIMNAT VALLEY [Selected Rolling Stock.-This comprises, for the present, nine passenger motor-cars, four trailers, one goods locomotive, a post van, and a number of goods- and other trucks. Each motor-car is equipped with two25-HP. to 30-HP. 500-volt direct-current single-reduction motors, made bythe British Thomson-Houston Company, two series-parallelcontrollers, two powerful handscrew-brakes,electrical brakes, and one trolley. Eachcar carries thirty-six passengers, eighteen inside and nineon each of the completely enclosed cabs or platforms, and is lighted by thirteen 16-candle-power lamps and heatedby four electrical heaters, the lighting and heating aloneabsorbing about 3 kilowatts per car. The car-frames are constructed on the Peckham system with abundant springs, and are provided with double-block brakes to each of the four wheels. The goods locomotive is similarly equipped, and is constructed to carry 3 tons of goods. The following are the weights and dimen- sions of the rolling stock :-

Tare. Load. Total Length over - 1 1 all. -- Weight. -- Tons. Tons. Tons. Feet. Inches. Feet. Inches. Passenger motor-cars ... 8.53-5 12 26 3 5 53 Goodslocomotive .....6.0 3.0 9 18 sg 5 53 Goods trucks...... I 3.0 5.0 8 15 5 6 62

The comparatively short wheel-base in relation to the length of the car is due to the fact that all the cars hadto be constructed to run over the sharpest curvesof the ZurichCorporation Tramways. Coat of Construction and EqzLipment.-The following are the costs of construction and equipmentfor the 73 miles of line complete :- € Landand compensation ...... 1 ,680 Earthworks...... 5 .120 Permanent way ...... 11,680 Works of art ...... 2 .080 Buildings ...... 5,520 Electricalequipment of line...... 7,840 Electric machinery in power-station ..... 2,400 Lighting,signals, tools, furniture, and sundries . . 1,000 Cost of removing and re-erecting telephone and alter-] ,ooo ing other electrical lines ...... Rollingstock, including electric equipment ...10,400 Administrationand engineering ...... 1,200 Interestyduring construction...... 2,080 Total ...252,000 equal to 26,933 per mile.

Working.-The line was opened for traffic in.Apri1, 1901, the constructionhaving occupied exactly 12 months. So farthe average consumption of energy measured atthe three-phase motors is 960 watt-hours per car-mile, or about the same as that ofthe Zurich CorporationTramways. Under exceptionally un- favourable conditionsof adhesionin winter, themaximum, including lighting and heating of cars and passenger-huts along the line, reaches 1,600 watt-hours per car-mile. The average losses in the high-tension transmission and in the motor-generators being 25 per cent., in the continuous-currentline 10 per cent., and in motors and gearing 20 per cent., the total efficiency of the system is 0 * 75 X 0 * 90 X 0.80 = 54 per cent. at the car-axles, and 75 per cent. atthe continuous-current dynamos. The cost of the three-phase current is Id. per kilowatt-hour de- livered at the three-phase motors, equal to l -34d. per kilowatt- hour of continuous current.Including depat lighting and the motor of the repair-shop, thetotal cost of threephasecurrent amounts to 1 -0Sd. per car-mile. The total cost of working is :-

Per Car-mile. d. Power...... 1.05 Wages and repairs of electric equipment. ....1.35 Maintenance of line, permanent way and cars ...0.41 Traffic...... 0.87 Administration and generalcharges ...... 0.42- Total ...4.10- The staff, exclusive of that of thecentral offices, consists of Lhirty-six men, equal to about five men per mile. The service is run in connection with the Zurich Corporation system, viz., the 15-minute service of theLimmat Valley Railway connects alternately with the 6-minuteservice of the Corporation Tram- ways. Theauthorised fares in competition withthe North- Eastern Railway average *d. per mile, with Id. fares for inter- mediatedistances and 20 per cent. rebate on return tickets. In further competition with the North-Eastern Railway, the Limmat Valley Railway was obliged to issue cheap season-tickets at the POW rate of 0.15d. per mile. Experience will show whether such low rates are remunerative, however much they may benefit the public. The ratesfor goods traffic are 2 * 3d. per ton-mile for goods in bulk and 4-6d. for other merchandise. Conclusion.-The Limmat Valley Railway is at present to some extent handicapped by its competitor, the North-Eastern Railway,

Downloaded by [ Purdue Univ Lib TSS] on [14/09/16]. Copyright © ICE Publishing, all rights reserved. 352 PRELLER ON THE LIMMAT VALLEY RAILWAY. [Selected inasmuch as the Federal Government makes the transhipment of passengers at thelevel crossings compulsory. Hence it is proposed to replace these crossings, which, under all circumstances, are little more than undesirable makeshifts, by subways, towards the cost of which the trunk railway is legally bound to contribute one-half. The Limmat Valley Railway hasalso obtained from the Cantonal Governmentrunning-powers over the ZurichCorporation tramways, and when these powers have been confirmed by the Federal Government the Limmat Valley Railway will be able to extend its service into the centreof the town. A question of considerable importance for tl suburban light railway of this kind is the supply andcost of electrical energy. The Linlmat Valley Railway had, at the outset, the option of either producing its own power by Dowson gas or steam plant, or of having such gas supplied by the Zurich Corporation Gas Works, situated in close proximity, or of renting high-tension three-phase current from the Zurich Corporation Central Station. It was found that the last-mentioned course would be, for the first few years, the most convenient and economical, the more so as the price of Id. per unit for the primary (three-phase) current, or 1.34d. per unit of continuous currentis moderate, having regard to the high cost of coal in Switzerland ($1 10s. to $1 12s. per ton). Never- theless, with a view to further economy, it is now proposed to obtain the supply of energy by long-distance high-tension (20,000 volts) transmission from a large central station of about 10,000 HP., which utilizes the power of the River Aare near its conflu- ence withthe Rhine, about 25 miles distant, and willdeliver three-phase current at the power-station at the rate of about $d. per unit, i.e., at half the price which the Limmat Valley Railway is paying at the presenttime. The works of construction and the electrical equipment of the railway were carried out under the direction of the Author as Chief Engineer and Managing Director of the Company, Messrs. Brown, Boveri and Co., of Baden, Switzerland, being the general contractors.

The Paperis accompanied by nine sunprintsand drawings, from one of which the Figure in the text beenhas prepared.