How UTO keeps them running
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. . . for half a million arduous African miles
by P. A. C. BROCKINGTON, MIMechE "ALWAYS something new out of Africa' wrote Pliny the Elder, the Roman writer, it AD 70. Today, the African is having a no destiny thrust upon him in the form o industrial progress, and learning about thi technicalities of road transport vehicles is al essential part of his education.
When I met Mr. P. C. Wickens, technica executive of' United Transport Oversea Ltd., Berkeley Square House, London, W (in AD 1969), he had just returned fror. Central Africa where he had seen the nev developments at close hand. Since Pliny' day the wind of change has created greate opportunities for new ways and Mi Wickens emphasized that communication in basic physical form, and understandin by Africans of the technicalities involve( was essential to a continuous improvemen in productivity on which the welfare c African countries depends. Mr. Wicken was a chief engineer of a number of BE undertakings from 1950 to April of thi year when he joined the UTO company.
He explained that a p.s.v. policy had bee established by his company over the year based on the use of two types c vehicle--town and country—with a emphasis on simplicity, reliability and Ion life. And dealing with freight vehicles h outlined how forward planning of th company aimed at establishing comparable policy in face of much wide variations of need and unpredictability c demand, and that in the meantime a polic of horses for courses had been a necessit dictated by events and availability.
It is evident that UTO is playing a important part in developing aptitudes the Africans in the countries in which tb UTO companies operate. These incluc Kenya, Malawi, South Africa. Swazilant Tanzania, Uganda and Zambia.
Corrugated and potholed roads, dust wit phenomenal powers of penetration, droughl and floods, high ambient temperatures an varying altitudes are features of roa transport (with variations according to th season) that are common to all Africa countries. Both town and country bust
cover large mileages compared with p.s.v. i this country and a country bus may t
away from base for seven or more days. Spares supplied by vehicle makers are costly by virtue of freightage charges and in some cases import duty. While up-to-date maintenance facilities are available in all centres, ease of replacement or overhaul is essential to high productivity, and predictability is of first importance.
Maintenance records are planned to indicate in advance what will be required in the near or more distant future, so that each vehicle is maintained to a stipulated standard with the minimum of work. An average life span of 500,000 miles without replacement or major overhaul of the power unit is obtained. from the basic types. And this will be the target for freight vehicles when it has been possible to establish a workable policy covering a large percentage of the total vehicles employed.
Typifying the mileages covered by country buses, the average July mileage of the 78 buses operated by East African Road Services Ltd. of Nairobi (with depots in Kisumu, Mombasa and Nakuru) was 7,632, while the 122 town buses of the Dar-es-Salaam Motor Transport Co. Ltd. of Dar-es-Salaam (with a depot in Tanga) averaged 4,509 miles in the same period. The mileage covered by a particular bus in both cases could well have been as much as 40 per cent up on these averages.
UTO operates a Continental make of vehicle as well as a make produced in this country, and p.s.v. fleets comprise Albion and Fiat buses in addition to other makes of vehicle that have been acquired Itit the course of takeovers and have not as yet been replaced.
UK 'mediums' Mr. Wickens praises the qualities of UK vehicles in the medium range, in particular the Albion CD27 and CD23 buses, powered by Leyland 400 diesel engines used respectively on town and country services in East Africa. These units are regarded as "near ideal" for the service required of them. Slip-fit liners are a feature that promotes ease of maintenance and the nitrided crankshaft has an indefinite life. About 80 per cent of the buses operate 500,000 miles or more without removal of the engine from the chassis.
To accommodate the higher loads carried in South Africa and variations of altitude (up to 6,000ft) Albion CD29 chassis are employed on town and country bus services in that country. These are powered by the Leyland 600 diesel and because of the greater weight of the engine compared with the 400 unit, the wheelbase is reduced to 18ft to increase the rear overhang, which compensates for the additional engine weight. The CD23 has a wheelbase of 21ft, while the wheelbase of the CD27 is 19ft 4in.
Albion town buses in East Africa and the CD29s in South Africa are equipped with Pneumocyclic semi-automatic gearboxes, while the standard type of five-speed manually operated gearbox is fitted to the country buses. Both -types have hub-reduction gearing which is highly favoured; presumably because of the reduced loading such gearing provides, the back axle is the most reliable of all the major chassis components. In Mr. Wickens' words, "the maintenance staff don't know the buses have got back axles".
In accordance with the current policy of the company, country buses are replaced after six years and town buses after eight. Until a short time ago, the average life span of both types was, of necessity, considerably greater than these maxima. Earlier renewal has enabled maintenance to be organized more economically.
Fuel consumptions vary considerably according to route but typically a town bus returns an average of about 8.5 mpg, and a country bus averages around 10.0 mpg. Overall dimensions follow UK practice except that the 40ft-long vehicle is not being used at the present time.
Structural strength is a first consideration in the design of the all-steel bodies which are locally built to UTO specifications, and it is notable that a good appearance and interior cleanliness are prionty requirements. The bodies of the East African buses have frames of standard (easy-to-get) angle sections and are of welded/riveted construction, aircraft-type riveting being employed for the attachment of panels in areas where it does not detract from structural strength to provide for easy renewal. In South Africa buses are fitted with lighter bodies based on top-hat sections which are welded and riveted, this type of construction being more suited to the requirements of the South African bodybuilding industry.
Interior fittings are of a "relatively high standard", all seats being fully upholstered and on the country buses a full-length luggage container on the roof provides for the bulky packages normally carried by long-distance passengers. Fluorescent lighting is being progressively introduced.
Dust problem In the higher weight category of freight vehicles operating at a gross load of about 40 tons, Continental and American makers are currently favoured by Mr. Wickens with the qualifications that UK manufacturers may "catch up with the Continentals" in the not-too-distant future. Because of the dust problem, turbocharged engines would not be employed by UTO in Africa and the company's need of a naturally aspirated engine developing 280 bhp (to afford a power-to-weight ratio of 6 bhp /ton) cannot readily be accommodated by makers in this country. The spares service offered by a maker could be a deciding factor in the choice of a vehicle.
Because of the arduous operating conditions the maintenance of bus suspensions is the most serious servicing problem. In East Africa replacement front springs for Albion buses are produced by a UK specialist company and include two additional rebound plates, located on top of the main leaf (they do not increase the rating of the spring) and a single additional leaf is fitted under the main leaf to give extra support for the spring eyes. It has been found that a spring normally fractures on the rebound and the rebound springs in effect provide damping. Hydraulic shock absorbers rapidly become useless.
The current Albion suspension represents the result of development over a long period. Stiffening the springs increases the load on'the hangers -and fitting more robust hangers increases the load that is transmitted to the chassis frame. While the suspension of the Albion is now satisfactory, the Fiats are still in the "problem stage". The suspensions on country roads give a harder ride that would not be acceptable on a tarmac surface, but Mr. Wickens would not consider using a more sophisticated suspension until the system had been fully proved in arduous service. And it would have to be simple; current air suspension designs are too complicated.
Springs are inspected after every trip and any fractured lead is renewed. While main leaves are imported from the UK or Italy, secondary leaves are normally obtained from a local supplier or are produced at the depot.
Out of the rainy season, vehicles normally create a cloud of dust, and it is virtually impossible to provide a dust-free atmosphere in the pits when a vehicle is being serviced. The dust problem is one that has had a marked influence on inspection and servicing procedures. Even the removal of a dip stick can permit the ingress of dust into the engine sump; and maintenance periods are extended to the allowable limit to avoid exposing working parts to the action of dust. The lubricating oil is, however, changed at frequent intervals (around 3,000 miles, compared with an average in the UK of about 10,000 miles) and a Supplement 1 grade (plus) of SAE 30 viscosity is used throughout the fleets. Oils of lower viscosity are not suitable for operations at prevailing ambient temperatures.
Air intakes are positioned in an area of least dust concentration which is often in the passenger compartment. The filters are of the conventional oil-bath type and it is considered that their design could well be improved upon. Consideration is being given to the possible use of other types, and the American Fast filter (which has a paper element) is being used experimentally. This is fitted with a depression warning device.
It is not expedient to employ a high-miler type of tyre with a thick tread (that can be re-cut) because higher-than-normal ambient temperatures and loading require that the tread has good heat dissipation properties. Outcrops of rock frequently cause impact damage and the average mileage life of a tyre is around 40,000 compared with an average in the UK of, say, 100,000. All tyre maintenance is performed in the company's depots. Choice of tyres Various types of tyre are being used experimentally and radials are employed as well as the cross-ply covers. In most districts the choice of tyres is limited and employing tyres that were not in general service would be uneconomic. Mr. Wickens would favour employing tubeless tyres based on 22.5in. rims if the practice were expedient. Re-treaded tyres have a mileage life that is approximately 60 per cent of the "new" life.
As much as six .months may be saved by employing air instead of sea transport for the import of spares with an equivalent reduction in the time that the capital involved is "tied-up", which can be a boon to overall vehicle utilization. UTO has recently acquired a controlling interest in Hill and Delamain Ltd., air freight forwarders, and increasing use is being made of air transport for the carriage of spare parts.
While servicing of both p.s.v. and freight vehicles is performed at regular stipulated intervals, maintenance is a flexible procedure in that it allows for the initiative of the fleet engineer to authorize replacements, repairs and overhauls in advance of need as shown by the records of oil consumption, wear and so on. A thorough inspection is made of every vehicle after 1,000 miles running or at the end of each trip, and at 3,000 miles filters are changed in addition to the engine lubricant. At 10,000 /15,000-mile intervals, the inspection also includes detailed checks of the engine, transmission, and running gear and after 80,000/100,000 miles the engine is given a bottom overhaul as well as a top overhaul, the injector pump is recalibrated and various components are stripped, including the clutch, hubs and kingpins. A bottom overhaul includes (if necessary) the removal of big-end and main-bearing shells. The condition of the major components of the vehicles, notably the engine, varies considerably after a mileage of this order has been covered, depending on the type of route and operating conditions. Mr. Wickens emphasizes, however, that whereas overhaul procedures are elastic, inspection routines are rigidly enforced, which has obviated major breakdowns.
"Buses and freight vehicles don't mix when it comes to maintenance", and maintenance of the two types is separated in all centres with the exception of Malawi where the freight fleet is comparatively small. Rigids and artics of all types, tankers, low-loaders, collection-and-delivery vans and service vehicles are included in the goods vehicle fleets of the countries mentioned.
A mileage life of 500,000 without major overhauls is the target that is envisaged as a possibility for heavier types of articulated and draw-bar trailer outfits as well as rigids. Whether or not the more sophisticated high-cost vehicles that are available in this category would fill the bill is open to some doubt. Kenworth outfits are employed by UTO in Australia and in that country cover as much as 500,000 miles in 26 months! If vehicle utilization of this order were possible in Africa (which could be the case in due course) operating sophisticated outfits might well pay off. Their use would enable maintenance to be simplified and labour costs to be reduced.
Many of the UTO's freight vehicles in Africa are specialized outfits equipped to carry a particular type of load. For example, special trailers are operated by Natal United Transport Ltd., designed to carry sugar cane, side-tipping trailers have been built to carry slurry for gold mining companies, and (in Zambia) ore is carried in outfits comprising side-tipping prime movers coupled to side-tipping draw-bar trailers.