competition of steamers on the particular dates when vessels sail North with fruits and vegetables from Florida, and, again, to meet the situation brought about by the Seatrain Car Ferry which handles about a hundred loaded freight cars at a time from New Orleans via Havana to New York.

While accurate figures are lacking as to the extent to which cargo shipments of petroleum, grain, coal, lumber, ores, fruits and vegetables, etc., might move by rail, the totals are large.

The Federal Coordinator recommended that the railways should follow the lead of the water and pipe-line carriers in providing cargo rates, presumably based on as high as 5,000- to 8,000-ton shipments.

While comments on public policy are outside the scope of this report, it may at least be pointed out that rates on cargo shipments equivalent to 80 or 100 railroad carloads are available via pipe lines or waterways, but not by rail.

Pipe Lines

The least conspicuous, the most efficient (within its limits), and the most successful economically of all present forms of freight transportation is the pipe line.

Operations of pipe lines in 1932, as reported to the Interstate Commerce Commission, show 93,000 miles of line, 83 million tons of oil originated, and a gross investment of 764 million dollars. The total of all petroleum pipe-line mileage is probably in excess of 115,000 miles, and these lines even through recent years have, as a whole, yielded a fair return on the investment-something that can be said of no other transportation agency.

California, Oklahoma, and Texas produce over 80 percent of our crude oil: East of the Mississippi River, where 70 percent of the population and the gasoline consumption is found, only 5 percent of our oil is produced. The solution of this has been forcing oil through 8-inch or 10-inch diameter lines of pipe, and this has been done with such efficiency that even waterways offer small competition save for such long hauls as from Texas Gulf ports to New York and Philadelphia. Less than 3 percent of the production of crude petroleum is handled by railroads, about 25 percent is moved coastwise, and the remaining seventy-odd percent travels by pipe line.

Of petroleum products, however, only 3 percent or 4 percent moves by pipe line, the balance being fairly well divided between the railroads and the waterways.

The oil is pumped by Diesel engines taking their own fuel from the line, or by electric power. Steam equipment, which formerly predominated, is pretty well confined to the territory east of the Mississippi River and is a relatively minor factor. Oil moves through the lines at about 3 miles an hour, and at 325

barrels per mile of 8-inch pipe and about 500 barrels per mile of 10-inch pipe some 40 million barrels are stored underground and are practically as permanent an investment as the pipes themselves.

It may be noted that in addition to this quasistorage in the lines the pipe-line companies and their owners, the oil companies, have about 400 million barrels storage capacity. Most of this storage is incidental to the purchasing, marketing, blending, and refining of oil rather than to its transportation.

No revolutionary developments in pipe lines are anticipated in the next 20 years, but the mileage of these lines is steadily and profitably increasing.

Exhaustion of oil supplies would, of course, upset the present pipe-line industry. Whether synthetic alcohols made from vegetable matter could be manufactured in our present oil fields or intermediate points is a problem we shall probably face during the present century but not in the immediate future. Something analogous to this has taken place in the conversion of at least one pipe line which formerly handled petroleum east-bound into a west-bound gasoline pipe line. Alcohol like gasoline, or for that matter water, presents no special problems from a pipe-line standpoint.

It has been suggested that pipe lines might be built to handle other commodities; certainly for quite short distances grain and coal may be moved in this fashion by compressed air. The cost of compressed air and the probability that any dry commodity would be reduced to a powder in an extended journey through a pipe, together with the difficulties experienced by the natural gas industry in keeping its pipe lines clean, lends small encouragement to prospects of this form of transportation.

Hydrogenation of coal probably offers a better prospect as the resultant liquid could, of course, be piped like any other fluid. It is also possible that coal may be reduced to a gaseous mixture and piped while in this state. Considering, however, the low value of coal, the remarkable efficiency with which it is transported by railroads, waterways, and even on short hauls by motortrucks, considering also the growth of natural-gas pipe lines, and particularly surveying the transmission of electric energy, it seems unlikely that piping of hydrogenated coal will be an important item in the next two decades of transportation.

If an abandoned pipe line could be acquired at scrap value, and were advantageously located to serve both a coal field and a coal market, it is conceivable such a venture might be commercially practical.

In the main, however, the petroleum and gasoline pipe lines are plant facilities of the oil companies, and their development in the next 20 years will depend upon the development of the petroleum industry it

self. Within their own relatively narrow field of transportation, pipe lines have a virtual monopoly of the crude oil business and will obtain an increasing share of the gasoline traffic. Their seemingly impregnable competitive position, however, arises from their ability to render a specialized transportation service more cheaply and efficiently than any other

agency.

It should be noted that pipe lines really do not deal as common carriers with the general public; the benefits of this kind of transportation accrue to the producers and refiners and only indirectly to the common

man.

Air Transportation Transport Operations

In the year 1926, 5,800 passengers were carried in the course of regularly scheduled air transport operations in the United States: our airlines are now handling over 100,000 passengers per month. How far the 5,800 hardy pioneers traveled is unknown; the average journey today is in excess of 400 miles. In 1937 the passenger miles flown on transport planes will probably exceed half a billion.

In 1926, 800,000 pounds of mail were carried, and in 1935 over 13,000,000 pounds.

Figures like these, marking the rapid development of civil aeronautics in the United States, can be compiled to wearisome statistical lengths. The amazing growth of aviation, the novel and spectacular nature of the industry, and the realization of man's age-old

dream of flight have combined to put flying first in the public mind whenever transportation is discussed.

Probably popular imagination as to this form of transportation is somewhat overstimulated. Passenger-miles flown in the Continental United States in 1933 were 173 million, as against 16 billion passengermiles handled by the railways and 185 billion by private automobile in intercity travel. While it is true that the transport plane passenger-miles almost doubled between 1933 and 1935, and will quite probably double again before 1940, we are still talking about a transportation agency handling only a fraction of 1 percent of the business.

We are also discussing a form of transportation that, while in many ways only on the threshold of its development, already faces definite fundamental limitations.

Short-haul traffic as between New York and Philadelphia is, of course, out of the question-from the standpoint of time alone the plane is inferior to the train. On longer hauls, as between New York and Washington, air travel may save an hour out of 31⁄2 hours, but for most people this is not enough to justify the safety factor and particularly the higher fare. Where airports can be relocated closer to large cities, air transport will profit correspondingly.

In addition to regularly scheduled transport operations, which in 1935 involved about 350 planes in do

44 An airway map of the United States showing scheduled transport operations is available from the Department of Commerce, Division of Aeronautics.

mestic service and 100 in foreign, we had about 8,500 licensed and unlicensed other airplanes in operation carrying a million passengers. A great many of these people merely made 10-minute sightseeing flights at airports on pleasant week-ends, but the figures also include strictly transportation flying.

Quite a number of companies and individuals own airplanes, and some flying is done in specially chartered planes, although the average rate for the latter sort of service is about 20 cents a mile. Charter operators carry passengers on flights which are not made on scheduled airlines-for example, from a city which does not have an airline to one which does, or at some particular hour.

Unless one has closely followed the amazingly rapid developments of aviation and generally unless he has actually flown, it is highly improbable that the average man realizes the present stage of civil aeronautics in the United States.

Air liners going into service in June 1936 are 21 passenger bimotored low-wing monoplanes with top speed of 215 miles an hour.

Air lines are now asking for a plane capable of flying 900 miles nonstop with 40 passengers, or 2,000 miles nonstop with 20 passengers and berths. Such a plane is to use four engines, each developing 1,000

horsepower at sea level and 900 horsepower at 9,000 feet altitude. A top speed of 230 miles an hour is asked, cruising speed of 210 miles an hour at 75 percent engine rating, and 193 miles an hour at 60 percent horsepower.

That present passenger planes rival any form of transportation in comfort and even luxury, and far surpass other agencies in speed, is generally accepted by the traveling public.

Unlike railroads, which have to own and maintain their lines and terminals, the transport airplane to a large degree depends upon Federal aids to air navigation and, of course, on the aid of cities for terminals. At the end of 1935 our principal airports were owned as follows:

As to the future the aircraft manufacturers and operators, who in the past have experienced extreme difficulty in looking ahead as much as 3 years, are naturally hesitant.

To date the factor of obsolescence has been disproportionately large from a commercial standpoint; ships have been changed about every 3 years in response to increasing demands for higher speeds, better accommodations, and larger carrying capacity. From this standpoint too rapid a development of planes would probably be unfortunate no transportation agency can long stand a 22 percent per month depreciation on its fixed capital.

It should be borne in mind that from the standpoint of physical depreciation alone the modern transport plane probably has a life of 8 or 10 years, subject to ordinary maintenance and the replacement of its engines generally after every 3,000 or 4,000 hours of flying. The accompanying photographs of the exteriors and interiors of planes of 10 years ago and of today show vividly the obsolescence which has made the actual physical life of a plane unimportant up to now.

Technical development of the planes themselves is slowing down; streamlining is pretty well worked out;

comfort has reached the stage where it is second only to speed as an attraction; the ships are tending to standardize particularly as to sizes; increased safety depends more on radio beacons and communication and well-planned and lighted landing fields than on improvements in materials or designs of the planes themselves; and from a strictly commercial standpoint the airlines will be in a better position as this slowingdown process goes on.

In the words of one of the leading aircraft manufacturers:

Efforts will always be made to increase speed, consistent with other factors, but the trend at the moment seems more toward safety and comfort than to the greatly increased speeds. Present speeds permit of quite fast schedules and in my opinion, the only pressing need for speed now is to give the airlines the larger margin to maintain their present schedules rather than to allow them to better their present schedules.

One technical development, however, will be the construction of a limited number of planes to fly at altitudes above 20,000 feet. At such heights cruising speeds around 240 miles an hour may be obtained without proportionate increases in operating costsroughly each thousand feet of elevation permits 1 per

cent increase in speed. At such levels, also, air conditions for smooth flying-regardless of disturbances below-will be advantageous.

From the standpoint of motors, controls, and flying technique, such operation will involve no unusual problems-most of the necessary work along these lines has been done by the military and naval establishments of the world. Much work, however, remains to be done to provide comfort and safety at these levels for the passengers who even today are sometimes unpleasantly affected by the rarefied atmosphere reached around 9,000 or 10,000 feet above sea level. This involves the design of a cabin in which the air is held at a comfortable pressure-not necessarily sea-level pressure, but materially more than prevails at the altitudes where a plane will fly.

Air pressures in pounds per square inch are as follows:

A difference between interior and exterior pressures of only 3 pounds per square inch would mean half a ton total pressure on a window 18 inches square. Translating such figures into the terms of a cabin 100 feet long, the problems of preventing distortion of the structure, leakage of the air, and at the same time holding weights within allowable limits are apparent.

If we had such planes today they probably could only be used advantageously on a limited number of nonstop routes-New York to the Coast and to Miami in the season, Chicago to the Coast, and possibly between Chicago and New York. Limiting factors are traffic density and the time and distance it will take such planes to climb to high levels and descend from them. Obviously to derive any real advantage from flights in the substratosphere planes must remain at high altitudes for an appreciable time and distance which is impossible except on such flights as suggested above. Extension of airline service will be made as traffic develops. The principal air routes are already established but some supplemental or feeder lines will be developed from time to time. From the public standpoint the most spectacular features in sight will be the extension of the Pan American Airways for passenger service, not only to Manila where mail and express