Electrified Railways- An. American Example

Progress, Volume XIII, Issue 2, 1 October 1917, Page 42

Electrified RailwaysAn. American Example

WILL LAWSON.

Among the dreams which New Zealanders permit themselves is that which embraces an electrically driven railway system, for which the power will be provided by harnessing the rivers and falls which are conveniently situated for that purpose. Some day, no doubt, this dream will materialize; and the Auckland-Wellington trunk line, among others, will he operated by electric trains. To the steady-going people— and politicians of this country, such a change appears to he something almost unattainable and only to be achieved after years of waiting. But in America they do these things quickly ; and the manner in which 440 miles of line of the Chicago,

largest locomotives in the world the steam engines that formerly hauled the trains were enormous monstrous in fact, if judged by New Zealand standards. The largest engine in the world is illustrated in these pages. It belongs to the Atchison, Topeka and Santa Fe line and its total weight is 387 tons. The engines of the Chicago, Milwaukee and St. Paul were not far short of this and their coal and oil hills were almost unbelievably huge. To-day the mountain torrents of the line supply all the power that is needed, and this power is delivered on insulated lines to 14 sub-stations, from which it is carried on the overhead wires (the dangerous third rail is not used)

Milwaukee and St. Paul railway, was converted from steam to electricity should interest those of us who hope for the ultimate electrification of the 425 miles which link Wellington and Auckland and the 369 miles of track between Christchurch and Invercargill. The length of railway to which electric power has been applied runs from Harlowton, Montana, to Avery, Idaho, and crosses the great continental linking range of mountains. It affords a smokeless, dustless and gasless main line route for 440 miles through the Rocky and Bitter Root Mountains and the line and its equipment are regarded as the last word in all those factors which conduce to the safety, comfort and pleasure of the travelling public. The total cost of the colossal work was £2,400,000 and it took three years to complete it. "What the change means may, perhaps be illustrated most effectively by comparing the two types of locomotives which, respectively, were employed before and after the change was made. While not exactly the

to the fast moving, powerful electric locomotives. There are no coal stacks, no cinder pits, no smoky engine houses. A coal stack has no terrors for the Chicago, Milwaukee line. And the cost of the power is much less than it was in the days of steam. Turn sumptuous de luxe trains, the “Olympian” and the “Columbian” provide a superb service between Chicago and the Pacific North Coast, and when these trains come to the mountain section the electric locomotives are coupled on and through the tunnels and water sheds that once were dread places of smoke and,sulphur fumes, the trains glide at an even speed. Grades are mounted with less effort than before. To give an idea of this immense advantage, a two per cent, grade— in 50, in other words—had to be surmounted for a distance of 20.9 miles on the last approach to the Divide; immediately west of the Divide, for a distance of 10.4 miles, there is a 1.66 per cent, grade; and on the western slope of the Big Belt mountains, for a distance of 40 miles, there is a 1 per cent, grade—where the line climbs 52.8

feet to the mile. These grades make steam haulage difficult for long, heavy trains, especially in winter. To-day electric locomotives not only haul heavier trains more smoothly over these grades, but travel at much greater speed than when steam was used. And weather makes little difference to them. The electric power is delivered, from the power houses to the sub-stations in 100,000 volt alternatingcurrent. At the sub-stations this is converted into a 3,000 volt direct current and in that form it goes to the locomotives. This reduction is accomplished as follows: The 100,000 volt alternating current is received through oil-switches, is conveyed to the high tension distributor, made up of three lines of copper tubings. From the current distributor the current is conducted through other oil switches to the transformers, entering at 100,000 volts and emerging at 2,300 volts —still alternating current. The next step is to convert to a direct current. The current passes through oil-switches and the motor generator sets and provides the power to operate

which there arc two, are of 4/0 size, and are specially made for high voltage electrical power. They are the largest diameter copper wire employed for this purpose. The so-called twin conductor trolley Avire has been installed after careful investigation and experiment. This form of construction permits the collection of heavy current through the tAvin contact of the pantograph Avith the two trolley Avires, and assures sparkless collection under all speeds. Under normal conditions, 42 immense electric locomotives arc required to haul freight and passenger trains over the electrified mountain districts of this raihvay. These locomotives cost about £22,400 each. They Aveigh 284 tons each and Avill haul 3,200 ton loads up a 1 per cent, grade at an average speed of 16 miles an hour. Similar locomotives, geared for greater speed will haul 800 ton passenger trains over the same stretch of road at a speed of 25 miles an hour and on a level run, at 60 miles an hour. To appreciate the tractive strength of these electric Goliaths, let it be said that the present day Mallet-

them. These motors are of the 60-cycle synchronous type which means that the current changes its direction sixty times each second. Each set generates a 1,500 or 2,000 volt direct current and the two generators employed, being permanently converted in series, delivers a combined direct current of 3,000 volts, which is the highest voltage direct current that has been adopted for railway work in the world. By way of comparison— direct current used on electric tramways is only 550 volts. After passing through the control switches the 3,000 volt current is conducted to the feeder and trolley lines and, through the pantagraph—as the trolley frame is called— to the motors of the locomotive. The overhead equipment presents some unusual features. To eliminate any likelihood of the trolley wire breaking and falling to the earth, a strong steel cable, called a "catenary" runs just above the trolley wire and parallel to it all the way. From this cable the trolley wire is suspended by hangers at short intervals. Single poles, each bearing a bracket support the catenary and it supports the trolley wire at curves and in station yards, "cross span" construction is used. The trolley wires of

steam locomotive has a tractive force of 76,200 pounds while these electric locomotives have a tractive power of 85,000 pounds. They measure 112 ft. 8 in. in length and are driven by separate motors twin-geared to each of eight pairs of driving wheels. The cab extends over nearly the whole length of the locomotive. There is a sermon for New Zealanders in this achievement of an American railway company. The cost of electrifying a similar stretch of line in New Zealand, moreover, would not be as expensive. Train loads are much lighter here. Where an American passenger train load runs to 800 tons, the express train in New Zealand rarely exceeds 300 tons, and freight train loads are likewise much less. This would mean that smaller locomotives, lighter lines, and lower power would be required. And the initial cost would be the heaviest. What the exact saving in running charges will be, have yet to be ascertained ; the electrical operation of the Chicago, Milwaukee and St. Paul mountain section, began last year. But it is certain— certain, in fact, before the work was undertaken, that the saving would be considerable.