Fewer Buses and Less Stai Yield Higher Revenue
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by P. A. C. Brockington, A.M.I.Mech.E
IN introducing measures to meet rising costs, the Urban District Council of Aberdare Transport Department have had to take account of the long-established habit of the local population to accept walking as the normal means of travelling. This custom is of pertinent consequence at the time of a fares increase; walking several miles over hilly country from home to the mine was general practice on the part of the breadwinner a relatively feu years ago.
In the past four years, economies have been introduced which have offset the upward cost trend and have reduced working expenses by more than 1 per cent.. This has, entail&I a reduction in fleet strength of some 20 per cent: and a corresponding reduction in staff by normal wastage. However, the number of vehicles operated at peak times to meet public requirements have remained substantially constant, and the revenue of the undertaking is somewhat higher than four years ago.
The average distance between stops has been increased on most routes, a crush-load single-decker has been commissioned, one-man bus operation has been introduced and bus sizes have been more accurately matched to individual requirements. Average speeds have increased and frequencies have been adjusted more realistically to public need.
A new depot is nearing cOmpletion. and this will provide for the garaging and maintenance of the refuse collectors and other machines of the Town Engineer's and Surveyor's departments, as well as the 35 buses in the fleet. All the vehicles will he housed under one roof in separate sections. A variety of maintenance economies has been applied to the bus fleet, and maintenance or the Surveyor's vehicles will be progressively reorganized on similar lines.
Ancillary to these measures, a minibus will shortly be run experimentally on a multi-purpose basis, including operation on new routes. The number will be increased if the experiment is successful.
The fleet comprises an approximately equal number of single-deck and double-deck buses of A_E.C., Guy and Bristol manufacture, and one Daimler double-decker. Extending the use of double-deckers is impossible on 50 per cent. of the routes because of very low bridges in the area. Routes are "reasonably• hilly," with steeper gradients of around 1 in 10 on radial services to districts some distance up the sides of the valley. Two valley routes combine to form a cross, the main route extending from Hirwaun to Glynhafod, a distance of about seven miles. The greatest distance operated across the valley is from Bwllfadare to Abernant, the combined route length being nearly 31 miles. On the Hirwaun-Glynharod route, buses run to Rhigos trading estate some two miles outside the U.D.C. area. Total route mileage is approximately 25, 17 of which are within the U.D.C. boundary. The population of the area is nearly 40,000.
Six A.E.C. Regal single-deckers and Mk_ III Regent double-deckers are used, equipped with 9.6-litre .engines, with seating capacities of 35 and 56 respectively. Powered by Gardner 6LW oil engines, four Guy light underfloorengined chassis have been in operation for over three years. One of these vehicles is equipped with a 40-seat body with accommodation for 20 standing passengers and will shortly be converted to one-man operation, whilst two of the remaining three vehicles of this make, having 44-seat bodies, have been one-man operated for some months. The standee vehicle was modified after delivery, to incorporate a central exit in addition to the standard front entrance to speed up unloading. Other Guy vehicles in the fleet are Arab Mk. IV 64-seat double-deckers and Arab Mk. Ill 56-seat double-deckers and 35-seat singIe-deckers, the total number of this make being 17.
Bristol vehicles comprise five K-type double-deckers and six 1-type single-deckers, .both types being equipped with A.E.C. 7.7-litre engines. The Daimler double-decker is powered by a similar unit and is equipped with a fluid flywheel and preselector gearbox.
In the last financial year for which records are available (ending -March, 1960), the vehicles in the fleet covered a total distance of 907,678 miles and carried 94 m. passengers. Whilst the total revenue per mile was 47.79d., the average fare per passenger was 4.54d., which compares with an average operating cost per passenger of 4.07d. Including overheads, but excluding loan redemption and interest, the total working expenses were 42.5d. a mile. Other statistics include an average fuel consumption of 9.64 m.p.g., based on a total consumption of 94,000 gallons, and a maintenance charge, excluding tyres, of 5.03d. a mile.
The relatively high pence-per-mile figures are largely a reflection of the substantial cuts which have been made in the annual mileage operated. Because of the reduction in fleet strength over the past three years, no new vehicles have been purchased, but a normal programme of replacing three or four vehicles a year has now been introduced.
Some of the older vehicles have been running for 12-13 years and have covered over 500,000 miles. Although major overhauls can be performed in the fully equipped workshops, A.E.C. factory-reconditioned units are used and Gardner engines arc overhauled by local agents, a 1:10 number of spare units being kept in stock. Power units are normally replaced after the vehicle has covered about 300,000 miles.
Preventive maintenance involving major overhauls or replacements is performed "as required" and is based on a comprehensive record system, which enables the maintenance supervisor to check the history of virtually every chassis and bodywork component preparatory to a dock, in addition to fuel and oil consumptions. He is thus provided with an accurate guide to the life expectancy of the components, including the power units, the m.p.g. figures affording a reliable indication of engine overhaul requirements. This assists in future planning as well as providing a reduction of diagnosis time when a vehicle is docked.
A particularly interesting example of the records made relates to the repair of timber bodies, with which about 30 per cent. of the vehicles are equipped. Printed drawings of the body framing arc marked after an overhaul to show parts of the structure that have been replaced by new members and to indicate the extent of the work that will probably be required in the next overhaul. In effect, the records give a detailed account of the daily work performed, of fuel and oil consumption in four-weekly periods, and a list of all but very minor mechanical failures throughout the life of the vehicle_ Maintenance checks comprise an A-dock at 15,000-mile intervals, a B-dock after 60,000 miles and a C-dock after a mileage that is normally decided by the condition of the power unit, or in some cases by the need for re-certification.
A novel form of wording is used for certain items on the doCk sheets which simplifies procedure, but (with the aid of a record system), ensures that the vehicle is not returned to service with components that are likely to fail before the next dock. The instruction "do or do not" against a number of items is modified by the maintenance supervisor to show whether a component or unit is fit for further use. or whether it should be changed.
It is significant that, since the introduction of Supplement 1 lubricating oil some 31 years ago, there have been fewer "do's" and a larger number of "do nots," with regard to engine assemblies. One grade of engine lubricating oil of S.A.E. 30 viscosity is used for all power units and is supplied by Dalton and Co., Ltd. Sump oil is changed at mileage intervals of 5,000-6,000, the optimum period between changes being originally decided by a series of analyses of used oil Old oil is now returned to the oil company for re-refining, the yield being in the order of 70-80 per cent. Formerly, used oil was sold locally for 2d. a gallon and, taking this into account, re-refining affords a saving of over £30 annually. Performance records show that processed lubricant has substantially the same properties as new oil.
A universal lubricant is also used for all the transmission units, including gearboxes and back axles. This is an S.A.E. 90 grade oil, treated with varioas additives which render it suitable for worm, spiral-bevel and hypoid gears, as well as spur gears. A concession is made, however, to the high unit stresses of new hypoid final-drive gears during the running-in period by using the lubricant recommended by the makers until it is drained at the stipulated period.
• Controversial Subject
One of the most controversial lubrication subject& relates to the use of molybdenum disulphide, and it is therefore of special interest that steering swivel pins are dipped in this lubricant, mainly with the object of eliminating stiffness, which otherwise might develop in the steering gear when the buses are in service. Following this successful application, molybdenum disulphide will later be applied experimentally to steering ball joints and possibly to the timing chains of certain engines.
Michelin X tyres are employed throughout the fleet on a contract basis, and their use is considered to be favourable with regard to the overall mileages obtained and also to the life of road springs. Butyl inner tubes are fitted and these appear to retain their rated pressure extremely well. it is considered that this factor alone promotes longer life as it practically eliminates running with under-inflated tyres.
The effect of Michelin tyres on fuel consumption cannot be accurately assessed, but, in the past few years, an increase in passenger density has not increased fuel consumption to the anticipated extent. The tyres are said to be easier to change than other types.
Considerable loss of coolant from the radiators of a number of engines formerly created unnecessary daily servicing work, many radiators having to be replenished with up to a gallon of water at the end of a day's run. Following successful experiments with a remote header" tank located at a high point in the cab (which involved a great deal of costly plumbing) a simple system was devised. which has reduced water consumption to an average of 10 pints in three weeks.
The filler extension of the existing radiator has been replaced by a filler neck of modified shape, the watertight cap of which is some 5 in. above the normal position. An internal air-bleed pipe connects the free air space under the cap to the cavity below a small dome fitted to the top tank • of the radiator at the front end. The only other modification is a baffle plate between the radiator and the filler neck, the cap space being provided with a non-pressurized overflow in the normal way.
This simple layout raises the water level by some 4 in. and prevents mixing of air with the water when it is poured into the top tank. This, it is considered, largely eliminates air entrainment, and the circulation of air bubbles through the cooling system_ These may be expanded in a hot zone and cause a large volume of water to be discharged from the cooling system.
Refuse collectors in the Surveyor's fleet of the Central Transport Section comprise Albion chassis, fitted with Eagle Speedyload bodies, Shelvoke and Drewry standard sideloaders and a Ford 10-cwt. collector. Shelvoke and Drewry fore-and-aft collectors have been ordered.
Other vehicles include a gulley emptier and a variety of tippers and vans, the total fleet numbering about 20. In addition, there are a number of rollers, bulldozers and so on. Most of these vehicles and items of plant are fitted with Smiths engine-hour recorders, and maintenance is organized according to the hours run, rather than mileage. Engines of the older vehicles are operated on premium grade lubricating oil, but Supplement 1 oil will be universally employed when these units have been overhauled.
Undercover garage accommodation is provided for all buses, the main parking section being equipped with a double-length greasing pit, fitted with a self-evacuating lub"ricant drainer from which oil is fed to an underground tank. Hose-reel greasing equipment is used, the temperature of the storage tanks being maintained by a thermostatically controlled heater.
The section is equipped with folding doors on the side opposite the workshops. An extension of the building on the far side is used as a refuelling bay and normally provides vehicle access through one of two folding doors, the door in use in bad weather depending on wind direction. Workshops and stores are arranged at right angles to the main garage section and parallel to the Central Transport Section, which is located on the opposite side to the refuelling bay. Although the two sections are separated, a central stores is common to both, and the main offices, located in the angle between the sections, give ready access to all parts of the building.
Transport Section Equipment
Wheel aligning is performed with the aid of a Dunlop optical gauge, and other items of equipment include a pit and a hoist in the Central Transport Section, a Widney bus washer (equipped so that fluid may be recirculated from an underground tank if required), a Laycock hoist, a Weaver steam cleaner and an Autoboiler gravity-fed coal burner.
The experimental minibus will be a Trojan Rural Bus 14-seater equipped with a Perkins P.4 oil engine in place of the standard P.3 unit. Modifications will include a driver-operated sliding door (and other fittings to facilitate one-man operation), a destination box. heating-anddemisting equipment and four roof lights. The bus will operate on periodic high-frequency services on new shortdistance routes. There will also be services on several extremely narrow approach roads to the town on certain days of the week and at times of the day, according to requirements. The vehicle will also be used as a„staff bus, for school services for disabled children, and for runs to an outlying hospital.
It is anticipated that increased use will be made of oneman operated single-deck vehicles of both high and normal capacity, and that the proportion of double-deck vehicles in the fleet will be reduced progressively.