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HORSES FOR COURSES down Walsall way
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Matching the bus to the job is an exciting exercise to the general manager of Walsall Corporation Transport. Many vehicles of the fleet of some 260 buses have been modified in important detail.
by P.A.C. Brockington, MIMechE
MR. R. EDGLEY COX has been general manager and engineer of Walsall Corporation Transport since 1952, and since 1954 a series of bus exhibits at Earls Court have borne testimony to his adventurous thinking.
This year the example was the Corporation's new 36ft Daimler Fleetline 86-seater with Northern Counties body, and when I inter viewed him recently he linked his regret at the decline of the trolleybus with the thought that electric traction motors would fit nicely into this big double-decker. A thought which
reminded him that the 1954 "show stopper-, a 70-seat Sunbeam 30ft double-deck trolley
bus, was the first bus of this length and capacity (bus or trolley} to be mounted on two axles; unladen weight was only 8tons 5cwt, Significantly it is anticipated that 36ft motor buses may eventually "take-over" on the trolleybus routes in place of the 22 70-seat and 33 56-seat trolleybuses which are used on a combination of routes, representing about 2.74 per cent of the overall route' mileage, that provides for circular running' between the Walsall bus station, terminals in housing estates and back to the station. Including eight single-deckers and two coaches the total fleet strength is about 260 vehicles.
Operation of the trolleybuses had to be curtailed following the abandonment of elec tric vehicles by Wolverhampton Corporation Transport and difficulties arising from the building of a bridge over M6. Unfavourable factors in the operation of trolleybuses include an increase in current cost since 1952/53 from 1.085d/unit to 1.8d /unit, (whereas the cost of diesel oil has been reduced from 3s 8d to 3s 3.35d over the same period allowing for the rebate of is 2d /gal), a shortage of skilled linesmen, high standing charges and a spares problem that is expected to worsen.
Operationally, trolleybuses have the disadvantage that they cannot be run on the "tidal flow" principle which involves return running with empty vehicles on alternative low-congestion routes.
During the expansion period of trolleybus operation from 1954 to 1960, 20 second hand buses (mainly Sunbeam F4s) were purchased for an average cost of £125. Some of these have covered around 200,000 miles with very little maintenance, the mileage covered by the F4As exceeding 500,000 in some cases.
The special advantages of electric traction, cited by Mr, Edgley Cox, are the smooth and rapid acceleration it provides, low maintenance costs and the facility with which the motors can be mounted in the chassis. Obtaining a similar type of traction from a dieselengined bus should, he considers, be regarded as a priority target and appropriately he is experimenting with a transmission he has evolved himself that would give progressive traction throughout the speed range.
Mr. Edgley Cox would favour turbocharging a diesel as a means of obtaining a high torque back-up and a near-constant-horsepower output from a small, light package. A Perkins turbocharged V8 might, he thinks, be the ideal engine for a 40ft bus with its revs cut down to say 2,200 rpm. It is hoped that a Perkins turbocharged engine will later be fitted in a Daimler 36ft bus which would enable the luggage space to be increased and might Well improve operational economy. A Daimler Fleetline 27ft 9in. double-decker has been equipped with a unit of this type as a proving exercise and it is notable that modifications to the head have enabled its fast idling torque to be increased,.which was necessary to match the requirements of the Daimatic semi-automatic transmission.
As far back as 1954 the Gardner 5LW engine of a Daimler 27ft double-decker was equipped with a BSA turbocharger and ran successfully for four years with one turbocharger change. This is a half-cab vehicle (it is still running) and the heat produced by the turbocharger )mounted on the right) discomforted the driver. But otherwise the experiment was a success; the bus had a better performance with no increase in fuel consumption and there were no indications that wear and tear had been increased.
Incidentally this bus was the first doubledecker to be modified to carry 65 seated passengers, an additional nine seats being provided by a rearwards facing bench seat at the front of the lower deck and a row of extra seats at the front of the top deck. The vehicle is equipped with an SCG pre-selector gearbox which is not a popular transmission with drivers because of the effort required to operate the pedal.
About 15 1956 Daimler double-deckers in this category have Willowbrook all-timber bodies, similar to the bodies fitted to the trolleybuses, that Mr. Edgley Cox considers were "the lightest and besttype of structure obtainable at the time. The pillars are mounted on the chassis outriggers and are pierced to accommodate full-length waist rails, while the lower sections of both bulkheads are constructed of three-piece glued members. While the latest all-steel integral double-deckers are appreciably lighter than chassis fitted with timber bodies, Mr. Edgley Cox regrets the passing of timber construction and wonders whether it may one day be revived.
The 30ft 70-seat two-axle double-de„ak motorbus arrived on the scene in 1960 in the form of the Dennis Loline having an overall height of 13ft 61n. Seventeen of these vehicles were eventually purchased and are still in service. They are equipped with air suspension at the rear and have conventional front suspension. The air springs give a good ride and service life is satisfactory, but the ride is not much better than that afforded by the modern leaf spring.
In 1961 five Daimler and 10 AEC frontengined double-decker chassis were equipped with Willowbrook or MCVV 30ft 72 /74-seat bodies having a height of 14ft 6in., but although these vehicles were suitable for selected routes they were not acceptable for Black Country and allied services because their length would have increased overtaking difficulties. The first Daimler Fleetline 27ft 9in. rear-engined 65-seat buses of a fleet of
85 were acqui?-ed in 1965 and were modified in two redesign exercises, the second of which was applied to all Fleetlines to provide an extra five seats (to give a total of 70) and space ahead of the front axle for an additional entrance.
The first exercise involved elimination of the front overhang but this proved to be unsatisfactory because it upset weight distribution between the front and rear axles. A front-entrance of this type has since been approved by the MoT to facilitate one-man operation but pending its introduction it is being employed as a driver's door and the space used for luggage.
Mr. Edgley Cox would welcome one-man operation of double-deckers partly because it would reduce running costs and partly as an attraction to higher grade drivers seeking a higher 'wage. The fleet now includes 100 Fleetlines, in use and under construction, and 45 other vehicles with a forward exit, which could favourably be used for one-man operation. Its application would necessitate simplification of the fares structure which would have to be acceptable to passengers, and the speed of loading in congested areas would have to be considerably increased.
One-man operation was applied to a number of single-deck vehicles operating on "easy" routes, but the services were discontinued because of the dearth of passengers. The 10 single-deckers in the fleet comprise Leyland Royal Tigers having a capacity of 42 /44 seats.
Rear-engined vehicles are not favoured unreservedly by Mr. Edgley Cox on two accounts. Dirt quickly accumulates on the engine and its ancillaries and heat dissipation is impaired by virtue of the confined space. As an example of the ill effects resulting from poor dissipation, the life of a compressor in a rear-engine compartment is very considerably reduced compared with its life in a front compartment and a number of vehicles has been equipped with high-output compressors with watercooled heads to give a longer life. Grilles have been fitted in the rear side fins to improve ventilation of the compartment.
The distance of the engine from the driving seat is also regarded as a disadvantage notably with regard to the optimum use of semiautomatic gearboxes. In the case of frontengined buses this type of transmission has a relatively long wearing life which is attributed to the facility with which the driver can make ratio changes to conform with audible variations in engine speed. Abuse of the gearbox is difficult to avoid if the engine is barely audible.
A fully-automatic transmission would be approved by Mr. Edgley Cox given that it were efficient and ratio changes could be controlled to comply with the operational requirements of stage-carriage work. Of special importance, the control system would have to give freedom from "hunting" at critical loads and speeds. Eliminating driver responsibility for gear changing would have obvious advantages, in Mr. Edgley Cox's view, which might include an improved fuel consumption.
The latest Fleetlines are powered by Gardner 6LX diesel engines and it is notable that they return a somewhat better consumption than the Fleetlines fitted with 6LW5, the averages being 9.8 mpg and 9.6 mpg respectively, Allowance has to be made, however, for the fact that the more powerful engines are operating in comparatively new buses and that the buses are employed on longer routes, including the Walsall/Birmingham service. The average of the Lolines is around 9.4 mpg while the AECs average about 8.7 mpg. The only one of its kind in the fleet and at the moment "out of service", a Leyland Atlanteen averages approximately 8 mpg. In addition to the Royal Tigers, other Leylands include 10 1953 PD2 27ft double-deckers carrying Roe 56-seat 8ft bodies that are fitted with special luggage racks in the lower saloon.
The Corporation renewal policy is based on a motorbus life of 15 years, which is equivalent in a typical case to a mileage approaching the half million mark. All overhauls of mechanical components and bodywork are performed in the workshop apart from regrinding crankshafts and machining cylinder heads. A Gardner engine normally operates about 350,000 miles before a major overhaul is required.
A breakdown vehicle, four tower wagons and four vans and cars are radio controlled from the depot at Birchills and this facility has paid off handsomely in terms of vehicle utilisation and recovery. In an adjoining office a small works study team is engaged in planning methods applicable to component overhaul and body repair which has in many cases enabled the throughput of work to be substantially accelerated.
While space limitation precludes mention of all the many vehicle modifications and practices not included in earlier paragraphs, a random selection of items is given to indicate the scope of such activities. For example all Fleetlines are fitted with impregnated glassfibre panelling to reduce weight, to improve resistance to resonance and to facilitate repair. Illuminated advertising panels are fitted to the offside of a number of buses having Filon silk screens or paper advertisements and forward-entrance vehicles are equipped with Scotchlite rear panels as a means of identification. The panels warn the driver of the following bus that the position of the bus ahead will be behind the position occupied by a rear-entrance vehicle when it halts at a bus stop.
Air pollution
A number of Fleetlines have been equipped with a ventilation /extraction system in which air is drawn from rear panels in the upper and lower saloon to feed the engine intake, but the system has not been wholly successful. Judging by the condition of the intake filters, air pollution in the saloon is far greater than pollution of the ambient air (despite a reduction in smoking on the upper deck in recent years) and this could impair the life of the engine if frequent filter changes were not made.
Experiments with a high-output dust extractor have shown that a lot of dust is normally left in a bus after it has been cleaned. The extractor should increase cleaning efficiency and enable cleaning time to be reduced to less than three minutes. Moreover it should reduce the work of the cleaning staff inside the bus during the operation.
One of the 56-seat trolleybuses has been rebuilt to provide an extra five seats on the lower deck and four seats in the upper saloon. This involved increasing the wheelbase to 18ft 6in. by attaching a Bristol Lode kka frame member to the front of the chassis and the fitting of an 8ft front axle. Operationally the vehicle has an advantage over the standard models in that it is less prone to pitching.
In 1953, a 70-seat trolleybus was fitted out as a pay-as-you-enter vehicle with a sitting conductor but the experiment was a failure. Passengers disapproved of it and so did the staff. "Perhaps," observes Mr. Edgley Cox, "the only thing wrong with the system was that it was ahead of its time."