AMERICAN ALLS THE TUNE
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IN view of the enormous strides that have been made in the United States of America in the field of highpowered petrol-engined design, and the widespread use of such power units for long-distance goods haulage, it is surprising to find that the majoritY of large passenger vehicles in that country is oil-engined. A further paradox is that there is a small but noticeable
reverse trend in our own country, where petrol-engined coaches arc regaining popularity.
The modern American heavy-duty bus or coach invariably has an oil engine mounted vertically at the extreme rear. . A further cast-iron rule is that transit buses have torque-converter drives, whilst inter-city coaches have conventional constant-mesh or synchro mesh gearboxes, whilst a well-established trend is the use of air-suspension systems.
Refinements are Standard
Fully integral construction is widely practised and, on long-distance coaches, such refinements as airconditioning, reclining seats, individual reading lights, toilet facilities and tinted anti-glare glazing are no longer regarded as novelties. One-man operation of city buses is countrywide, the usual flat fare for any uni-directional distance being 20 cents (1s. 6d.).
The result is that the modern American coach is, by European standards, an extremely advanced design and surely one of the most luxurious means for transport to be found anywhere in the world, second only, perhaps, to ocean-going luxury liners in terms of cost to the passenger.
The progress apparent in the design of such long-distance vehicles has undoubtedly been accelerated by the travelling habits of the American people. id
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Cars, of course, are two a penny, as operators of urban bus services know all too well to their cost, but comparatively few people choose to travel in their own cars over long distances.
For such journeys, air travel perhaps offers the best, and quickest, means, and indeed most Americans look upon air travel in the same way that the British look upon journeys by bus. The two limiting factors in connection with this method of transport are unreliability of services, because of weather, and unavailability of accommodation should an aircraft be fully booked up.
The next alternative to air travel is the railways. Not by any means as swift but cheaper in the long run, the railways are preferred to air travel by many people. Some of the modern long-distance trains running in the States offer unrivalled facilities for comfortable travel with the minimum of inconvenience, but on such trains these facilities are, of course. available only at extra cost, and luxury accommodation is necessarily limited.
Realizing that, on the face of things, long-distance coach travel would have to offer substantial advantages to compete with these two other forms of transport, the bigger coach operators have had, over recent years, to concentrate on providing fast, reliable, comfortable and reasonably cheap transport in order to remain in business at all.
This is the prime reason for the American longdistance luxury coach being what it is today. Having such vehicles is, of course, only half the battle: they have to be backed up by efficient and courteous staff, by flexible vehicle allocation arrangements (to ensure that no passengers get left behind), and by concentrated and often expensive advertising campaigns.
This many-pronged attack on prospective travellers is paying off, however, and during the time that I was in the States I rarely saw a coach with more than a few empty seats, and frequently witnessed duplicate services . being run.
In many cases it even happens that coach services between town centres over distances up to 200 miles or so are only a little slower than services offered by airlines. For example, to travel by air from New York to Atlantic City takes 2-1hours from centre to centre, although the actual flying time is only 50 minutes. This 100-mile journey is covered by regular coach services in 24. hours at a cost of about £1 15s. return, whereas the single-air fare is £3 9s., plus another for Public transport to and from the airport at each end. This is not an isolated instance but one which can be found in almost any other part of the country.
It will be seen, therefore, that provided an American coach operator keeps fully abreast of current develop ments (and many of them formulate these developments themselves so as not to be left behind), he has little in
the immediate future to worry about. Indeed, only-by drastically speeding up rail and s air travel and correspondingly : reducing the fares—neither of which eventualities is _conceivable under _present conditions—will coach travel be displaced from the American
scene. It is possible . that coach travel will become even more popular with the vast 42,000-mile express highway programme that is under way. This will make for even faster road schedules, and is likely to take further traffic away from
the railways, as the tatter well realize.;
The' picture for the bus operator is not so rosy, however, because in this field the general trend towards the ousting of the city bus by the private car, which is seen all over the world, is even more pronounced in America. Operators cannot afford to offer the same degree of luxury travel that is available to long-distance travellers, as their buses must be capable of accomrno dating a large number of standees at rush hours. Double-deckers are not favoured because of the length of time taken to load and unload during these times.
Similarly, the marked distinction between peak and. off-peak services, which frequently is in the ratio of 4 to I, means that most operators must have much larger fleets than they can economically operate, and even charter services cannot be expected to make up this wide difference in daily requirements.
As opposed to the goods haulage business, where fuel costs form a low percentage of total operating costs, fuel economy is of importance to bus and coach operators; hence the use of oil engines. Another advantage endowed by the use of such units is the long life between major overhauls, 300,000 miles being a common figure. Unlike their haulage contempor aries, passenger-vehicle operators can be assured that their power units will receive regular maintenance at their home depots and that adequate supplies of oil fuel are available wherever vehicles go, even on long distance services.
Noise, which is, after all, one of the main reasons why petrol engines are still used in Great Britain for coaches, is not such a big consideration to the American operator, as one of the prime advantages of a rear-engined vehicle is that engine noise does not disturb the passengers so much as with forward or underfloor-engined designs.
The main criticism aimed at oil engines for passenger use is that they smoke. Inadequate maintenance is usually the reason for this, although sometimes it is because inferior-grade fuels are used. Whatever the reason, many States regularly attempt to formulate regulations to make such smoking illegal and to minimize its nuisance.
One of the usual " solutions " suggested by such authorities is that vertical exhaust stacks should be used, but tests made by various passenger-vehicle manufacturers have shown that these are not by any means the answer, as it has been proved that even with vertical exhausts, the fumes, which are heavier than air, drop to the road.
During my visit to America, I was able to visit General Motors CorporAtion's G.M.C. Truck and Coach Division factory at Pontiac, Michigan, which is about 20 miles north of Detroit. Here, coaches and buses are built in a self-contained plant which makes use of modern flow-line pro duction methods. The fact that never fewer than 100 buses of any one type are built as a production run in this plant enables full use to be made of press tools, drill jigs and prefabricated assembly methods, and a factor of 80 per cent, parts interchangeability between the various bus models is claimed. Each bus or coach type has its own complete set of press tools—mostly made by General Motors—and multiple-press-tool methods are used.
At this stage it is interesting to recall that this large bus production plant—indeed, public transport in the United States generally—had its beginnings in Great Britain, for the first taxicabs and buses to be used in America were imported from Britain to New York in 1907, being operated by the Fifth Avenue Coach Co.
Credit Goes to Britain
Five years later, Col. George A. Green, who had been with London's Vanguard Motorbus Co., and later with London General Omnibus Co., joined the Fifth Avenue Coach Co., and it is now generally agreed in America that much of the credit for the continued successful development of coaches and buses in that country must go to him.
In 1922, Col. Green joined the Yellow Motor Coach Co., in Chicago, whereupon it started to build buses, having until that time been concerned principally with the operation and construction of taxicabs since its formation in 1908 by Mr. Walden W. Shaw.
In 1935, General Motors merged, and the Yellow Truck and Coach Manufacturing Co. were formed, moving to the present factory site at Pontiac in 1928. Taxicab construction was discontinued in 1939, and in 1943 the name " G.M.C. Truck and Coach Division" was adopted. The Division is now about the largest in America to be devoted to the production of public service vehicles, and in many respects General Motors have led the way towards the successful evolution of present-day public transport.
For example, air suspension, the development of which was started over 14 years ago, is now standard equipment on all General Motors buses and coaches, except the small petrol-engined 31-seat urban bus. This form of suspension has, over the years, proved to be an outstanding success, not solely with passengers, who can appreciate the riding qualities of the layout, but also with maintenance engineers, who now have no suspension repair bills and fewer bodywork and transmission failures to deal with.
All General Motors buses employ integral construe Lion, with welded steel tubular and channel-section underframe members, extruded aluminium body pillars and roof rails, and riveted aluminium panelling. The tubular portions of the underframe serve also as air reservoirs for the suspension system.
Four basic types of bus are manufactured, the smallest being the 27-ft.-long 31-seater. This is powered by a 124 b.h.p. petrol engine working in conjunction with a four-speed Hydra-Matic automatic gearbox. The next largest bus is the 37-seater, whin is 30 ft. 91 in. long, has a 133 b.h.p. 4.6-litre four-cylindered two-stroke oil engine and a torque converter.
45 Seats: 35 ft. Long
A 45-seater, which has an overall length of 35 ft., is made, and this has a 7-litre six-cylindered two-stroke engine which is available with alternative power ratings of 172 b.h.p. or 184 b.h.p. This bus, and the two smaller versions, are available only as 8-ft.-wide vehicles.
A choice of either 8 ft. or 8 ft. 6 in. width is offered for the largest bus manufactured, the 39-ft. 9-in.-Iong 51-seater. At the time of my visit, the 8-ft. 6-in.-wide version of this model had proved to be the most popular bus yet made to date, despite the fact that its width prohibited its use in many States. The six-cylindered engine which powers these two buses can be obtained with alternative power ratings of 167 b.h.p., 183 b.h.p. or 211 b.h.p., whilst a torque converter is, of course, standard eqnipment. Despite their great length, these 51-seat vehicles are quite manceuvrable, partly because of the better lock made possible by the air-suspension layout. A turning circle of 73 ft. is quoted, which is only 2 ft. more than the turning circle of the 45-passenger model. The 30 ft. 9 in. and 27 ft. buses each have turning circles of 60 ft.
The design of the 41-seat inter-city coach is somewhat different in that the under-structure consists of two welded sub-assemblies, one above each axle, linked by longitudinal aluminium main runners which carry transverse aluminium bulkheads to separate the underfloor space into baggage compartments.
This arrangement leaves a baggage capacity of 197,5 cu. ft., with an extra 35 Cu. ft. available if airconditioning equipment is not fitted. This 41-seat coach, which is 35 ft. long and 8 ft. wide, is produced in one standard version only, but alternative seating layouts and the optional installation of toilet facilities at the rear are offered.
Power is supplied by a 211 b.b.p.. two-stroke oil engine mounted in unit with a four-speed constant-mesh gearbox, the complete assembly being carried, as with the buses, transversely at the rear of the coach and driving into the back of the rear axle through angle gears and a single-piece propeller shaft.
Slung from Roof
The engine mounting arrangement is interesting: the unit, complete with radiator and gearbox, is carried in a sub-frame which, at its forward end, is pivoted to the rearmost transverse member of the body framing. The rear of this engine sub-frame is supported by two vertical tubes which are slung from the rear roof canopy at waist-rail level. Hence the whole of the vehicle body, through the medium of the roof, supports the weight of the engine, and under-framing fatigue caused by such a weight being cantilevered behind the rear axle is eliminated.
During the construction of this bus, all the components used are rustproofed by Bonderizing, following which aluminium components are zinc-chromated, whilst steel pieces are coated with red lead. All inner surfaces which, in the assembled bus, will not be directly exposed to the atmosphere, are enamelled to prevent hidden deterioration taking place. This somewhat expensive
process has been necessitated by the fact that a minimum life of 10 years isdemanded by operators, and only by ensuring that complete weather-proofing is applied through the bus can such a trouble-free length of life
• be expected. Where it is necessary to use timber fillets, these also are proofed against climatic conditions.
I was given the opportunity of driving a bus and a coach while at Pontiac, and both these vehicles were unladen. This meant that I was unable to obtain performance figures, but it did have the advantage that I could witness the superior suspension characteristics of an unladen vehicle which has air springs. Driving either vehicle was effortless, particularly the bus, the torque converter of which made gear changing (other than the selection of forward or reverse) completely unnecessary. However, gear&zinging did not prove to be any hardship with the coach either.
The use of conventional transmissions in long-distance coaches is common practice in the States, it being rightly reasoned that once on the open road gear-changing rarely becomes necessary, as a result of which the added initial expense and slightly reduced operating economy of automatic transmissions are not justified.
Both vehicles were quiet in operation and even in the back seats the engine noise is certainly no louder than is experienced in most of the seats of a contemporary British underfloor-engined vehicle. This, of course, is not the main reason why 'rear engines have been so widely adopted in America: it is the greatly improved aczessibility of the unit and the more nearly equal weight distribution given that has appealed most to operators.
Noise and Heat
I was unable to obtain any definite pointers as to future developments in the bus and coach industry. The use of gas-turbine power units is not viewed as an impending possibility because there are still the three big problems of noise, heat and low fuel economy to be overcome. When taxed with the future of the freepiston gasifier type of power unit, working in conjunction with a turbine, the General Motors' officials would make no comment; For the most part, operators seem content with Present-day braking systems, although no recent developments have taken place in this field, and it seems that the most likely progress to be made in the next few years will be along the lines of increasing the life of engines and other running components and providing even greater fuel economy. Tubeless tyres have so far proved successful under varied operating conditions and are generally viewed with favour.
Few developments are warranted in so far as suspension is concerned, operators being more than pleased with the success of the GMC-Firestone air springs. For example, one set of air bellows fitted on a GMC transcontinental coach has shown almost no wear after three years of service, having travelled 619,000 miles.
Body-production techniques appear to be stabilized, and there is no noticeable trend towards the use of plastics materials. Indeed, from what I could gather, it would appear that some manufacturers have already tried plastics materials and had to drop the project because of higher costs and the high incidence of illness amongst the operatives working on such processes.