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The author describes a system of automotive transportation for intra-city hauling and the moving of merchandise between railroad terminals that has enabled the company he represents to serve the city of St. Louis and the railroad terminals there with a high degree of efficiency through the utilization of tractor and semi-trailer units and a thorough supervision of their movements. The units are described and illustrated, and the conditions governing their usage are set forth. The salient features of the paper include discussions of the necessity for adequate terminals, off-track versus on-track railroad depots, the volume of tonnage, tractor and semi-trailer operation and methods of procedure and control, weight and protection of loads, haulage distance, economy and a specific statement of the principal advantages gained through the use of automotive equipment of the type described.

The author discusses the factors that must be considered in solving the transportation problems and then describes the operation of the English-railway cartage-system in some detail under the two main divisions of delivery and collection. An important feature of the system is that of the control afforded by locating a controller, or dispatcher, in a central office and holding him responsible for the movements of the carmen, or drivers. The details of this control are explained. The field for the motor truck in railway-terminal service is outlined and a presentation is made of the merits and demerits of unit containers, together with an illustrated description of the English “fiats,” or demountable bodies. Other subjects treated include cartage costs, tonnage hauled, unified control of cartage and expressions of opinion quoted from numerous English trade organizations.

The author (Chicago Tractor Meeting paper) divides the history of the application of mechanical power to farm work into three periods, reviews each one and comments upon the various phases of progressive development that influence the type of tractor most desirable for satisfying present needs. The requirements of farm work are outlined, and the different types of tractor built and being constructed to meet these demands are reviewed, discussion of large versus small tractors, type of drive, power needed, control, methods of operation and the factors constituting general-purpose service being included. So far as adopting the tractor for farm usage is concerned, the author believes that the present limitation of such utilization lies with the tractor industry and with tractor engineers, rather than with the farmer.

A record of an investigation of heavy-duty truck-axles carried out by the Bureau of Standards at the request of the motor transport division of the Quartermaster Corps, this paper deals in particular with the mechanical efficiency of the axles tested. The investigation included, in addition to several worm-drive Class-B Army-truck axles with different types of bearing, a number of axles usually designated respectively as “internal-gear” and “multiple-reduction” type. Each of these types was represented by axles in successful use in commercial trucks of 5-ton rating. In analyzing the results of the tests it was found possible to separate the losses into no-load losses and load losses; the total loss being the sum of these two. In general, the no-load losses were primarily controlled by the viscosity and the method of application of the lubricant. They were greater in those axles in which the parts rotating at high speeds were immersed most completely in the lubricant.

The author quotes statistics relating to the proportion of closed to open bodies and outlines the changes that have taken place in body construction in recent years. He sketches the advances that have been made and states that the question to be answered now relates to what all this improvement in manufacturing methods has accomplished toward reducing the price of a closed-car body to the consumer. He compares the percentage of public benefit in 1922 with that of 1914, excluding the period of inflated prices immediately following the war, and states that it is 10 to 15 per cent, but says also that this is an unfair comparison because of the excessive increases in the cost of labor, lumber, sheet steel and trimming cloth. An unconventional type of body, covered entirely with fabric over a foundation of wire-mesh and buckram fastened to the conventional wood-framing, is illustrated and described in detail, together with a statement of its advantages.

The author states briefly the phenomenal growth of taxicab usage and consequent demand for this type of motor vehicle, mentioned the differences in body requirements for taxicabs as compared with those of passenger cars, and describes the methods used to secure durability in taxicab-body construction to discount the severe service to which the body is subjected. Tabular data are presented and comments made regarding the woods that are suitable for body framework, and the methods of joining frame members and reinforcing frame joints are outlined. The desirable types of roof and the factors that influence design are discussed at some length, illustrations being presented also, and minor considerations, such as types of hardware, dash and instrument-boards, are included. A brief summary states present conditions, and a bibliographical list is appended of informative publications relating to the subject.

The author enumerates the distinctive features of buses designed for city, for inter-city and for country service and comments upon them, presenting illustrations of these types of bus. Steam and electric motive power are discussed and the chassis components for bus service are considered in some detail. The general types of bus body are treated, together with the influences of climatic conditions and local preferences. Comfort and convenience factors are discussed at some length and the problems of heating, lighting and ventilation are given constructive attention. Fare-collection devices and methods are commented upon, and the State and local legal regulations are referred to in connection with their effect upon bus operation. Illustrations are included and a table showing condensed specifications for city buses is presented.

The authors enumerate some of the questions that are involved and, after outlining a previous paper on the subject of plows, analyze these questions in part by the aid of diagrams and applied mathematics. Comparative draft data are presented in tabular form and commented upon, as well as comparative hitch-length data. Tractor reactions are explained and discussed in some detail in a similar manner, special attention being given to the reactions on a slope and up-hill. The reactions on cross-furrow slopes are considered, comparisons being made between two tractors that were reported upon in the University of Nebraska tests. The factors involving tractor stability and resistance against overturn are analyzed. The authors state that the analysis presents a definite method of attack for the more correct solution of the proper hitching-point, as well as being a study relating to lug design.

In this day of transportation engineering, the requirements of each customer must be diagnosed accurately and the economic waste due to wrong selling eliminated. Stating that 32 classes of trades, divided into 350 sub-classes, use motor trucks, the author expresses the view that, in applying the science of selling by analysis, it is necessary to know the cost of shipping every pound of goods, deducing in turn the correct size of truck for a given kind of work. Referring to the fact that a truck cannot be designed to stand up under all conditions and that selling a truck which is unsuitable for a particular task means a dissatisfied customer, the author gives the opinion that a truck of mediocre merit will in many cases perform more satisfactorily than the best truck built operating under improper conditions.

Stating that asphalt, brick and concrete-slab road-surfaces are the only pavements that have given satisfaction for automobile traffic, the author believes further that thus far the concrete-slab surface is the only one worthy of consideration for such traffic. He discusses the merits and demerits of these surfaces and includes an enumeration of the factors that combine to produce a thoroughly satisfactory road surface. Passing to a detailed review of the bearing value of soils and the correction of road failures, the author presents data and illustrations in substantiation of his statements and follows this with a consideration of the reinforcing of a concrete road-slab with steel.

The author considers first the materials available for construction, in connection with the S.A.E. standard specifications, and presents a comparison of the different metals with comments thereon. In regard to metallurgical problems the designer's first task is to determine what the various stresses in the parts are and their magnitude; hence, a true appreciation of the terms “shock” and “fatigue” is necessary; a somewhat lengthy explanation of their meaning is given. The construction features of the different parts of the tractor are treated in general, no attempt being made to cover details; comments are presented on front axles, wheels, bearings, cylinders, valves, valve-seats, transmissions and gears. Heat-treating is then considered in some detail, three specific reasons for annealing before machining being given and five which are governing factors in regard to heat-treatment in general.

Before taking up the results of the tests, the author states briefly the provisions of the Nebraska tractor law, the kind of tests conducted and the equipment used. Applications covering 103 different tractors were received during the season; of the 68 that appeared for test, 39 went through without making any changes and 29 made changes. The results of the tests are described and illustrated by charts. The fuel consumption was studied from the three different angles of volumetric displacement, engine speed and the diameter of the cylinders, the tractors being classified accordingly and the results presented in charts which are analyzed. The weaknesses of the tractor as shown by the tests are commented upon at some length with a view to improvement of the product.

The paper treats of the service, commercial and technical aspects of the subject in turn. The author calls attention to the fact that there can be no such thing as free service, because the customer pays in the end, and gives a specific definition of service. He argues that the engineering departments should urge upon merchandising departments intelligent distribution through dealers, the stocking of an adequate supply of parts and the maintaining of a well qualified mechanical force for the purpose of making engineering development work in the form of farm power automotive apparatus effective. There is a great need for a suitable system of training mechanics for tractor service work, and there should be a definite plan to assure that men making repairs and adjustments in the field are well qualified.

To test tractors for results valuable to the user, the reliability, durability, power, economy and utility should be determined. Standard tests measuring tractor utility and reliability are impossible practically and durability tests would be an extensive project, but tractor and engine-power tests and tests of the amount of fuel required for doing a unit of work can easily be made. The University of Nebraska tests described were for belt and drawbar horsepower and miscellaneous testing for special cases. The four brake-horsepower tests adopted are stated. Tractor operating conditions are then reviewed. The drawbar horsepower tests include a 10-hr. test at the rated load of the tractor, with the governor set as in the first brake-horsepower test, and a series of short runs with the load increased for each until the engine is overloaded or the drive wheel slips excessively, to determine the maximum engine horsepower.

The feeling that a truly heavy-duty engine for truck and tractor service was not available led the company represented by the authors to commence the development of an engine that would be capable of high speed as well as have ability to develop maximum horsepower and torque at low or medium speeds. Five specific requirements are stated for a tractor and three for a truck engine; the requirements of a universal truck and tractor engine are then specified under six headings. The special features of design of the engine developed are described in minute detail and illustrated by photographs and charts, seven definite features being mentioned as having been productive of the desired results. The testing apparatus is described and power and torque curves, a timing diagram and capacity curves of the water and oil-pumps are presented. Gasoline was used as fuel, although the engine is designed to use either gasoline or kerosene and is said to be adapted to the use of the heavier fuels.

The best weight for a tractor of given horsepower must be a compromise based upon a mean of the many conditions to be encountered by a given machine or by different machines of the same model. While the weight logically will bear some relation to the drawbar pull, the latter in turn depends upon tractor speed. The next item is weight distribution, which requires the utmost skill of the designer; this is elaborated and diagrams are shown of tractors operating in comparatively firm and in soft ground, ascending a grade and when the drive-wheels are mired. The four-wheel-drive tractor requires a modification of the foregoing analysis and the diagrams are applied to afford a similar analysis for this type. The author's conclusion is that, while careful engineering will make the light-weight tractor of conventional type stable under most conditions, there is a possibility that any future trend toward lighter machines will open the field to other types.

Three distinct types of wheel equipment are best able to meet conditions in the field; the pyramid lug, the spade lug and the angle-iron cleat. The author mentions the merits of each type of lug, discusses slippage and states that no one kind of wheel equipment can be recommended as a universal type.

Kerosene has advanced to the front rank as a fuel for the farm tractor within a decade. A heavily preponderating majority of tractors burn kerosene. The history of early oil engines is reviewed and some comparative costs of kerosene and gasoline fuel for tractors, obtained from tests made in January, 1920, are given. Kerosene tractor-engine development is then discussed. The conditions required for complete combustion are the same in principle for both kerosene and gasoline, but in actual practice a wider latitude in providing ideal conditions is permissible for gasoline than for kerosene. The four classes of commercial liquid fuels usable in internal-combustion engines are the alcohols, the gasolines, the common kerosenes and the low-cost heavy-oil fuels. The alcohols rank lowest in heating value per pound of combustible. Under existing economic conditions neither alcohol nor the fuel oils require consideration as available fuels for the tractor.