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Transport engineering,1971:

by Paul Brockington, MIMechE

Autocar and Transporters Ltd

IT. IS REASSURING to find a stable element in the fluctuating misfortunes of the car industry. Car delivery is an essential branch of the industry and it has to be organized to cater for, production throughputs that in critical periods are unpredictable from day to day. The peaks and troughs of the business are non-conducive to organizing the delivery fleet on a productive bask. But it can be done and is done by the Distributor Deliveries Group of companies. And Mr S. T. Alton, managing director of the Group, anticipates that the possible introduction of factory-controlled delivery schemes by their main customers, British Leyland and Vauxhall, will enable traffic to be streamlined and fleet productivity to be increased.

Contracts will be made with the factories, and the availability of ample parking space at 12 storage sites with a total area of 94 acres will give greater scope for combining rapid clearance of completed cars from factory premises (which is the advantage of controlled delivery to the factory) and regular deliveries to distributors, the storage sites providing the necessary stocking facilities.

Fleet increase The predicted expansion of business in a period of two to three years that reorganization will promote, is indicated by the total number (186) of vehicles operated by the Group and the number of 0 licences granted, which totals 270. A fleet increase of more than 100 vehicles since 1966 can be credited to expansion as well as acquisition. The number of cars handled in 1970 was in excess of 258,000.

Ninety-eight vehicles or more than 50 per cent of the Group's fleet are operated by the Worcestershire company, Autocar and Transporters Ltd, of Wythall, some five miles from the BLMC Longbridge factory, and of the total storage space of 57.5 acres at three sites in the area, the Wythall site accounts for 43 acres.

Autocar and Transporters incorporates Car Transporters and South Birmingham Deliveries and the remaining four companies of the group comprise B. J. Henry Ltd, of Oxford (40 vehicles); Cheall, Knowles and Co Ltd, of Liverpool (four vehicles); Dependable Delivery Ltd, of Luton (42 Vehicles); and Bathgate Vehicle Deliveries Ltd, of Bathgate (two vehicles). Dependable Delivery incorporates the Safeway Delivery Co (Sadec Ltd) while Bathgate Vehicle Deliveries is a jointly owned company in which Distributor Deliveries has a 25 per cent holding.

Of the 186 vehicles in the Group, 141 are car transporters and of the 333 drivers, 131 drive transporters, the remainder being employed to deliver cars by road or on ferry-van duties. Sixty transporter drivers operate from the Autocar and Transporters Wythall depot, which is the administrative centre of the group.

Maintenance facilities at Wythall are geared to cater for all but a minority of the combined fleet and all major overhauls or repairs are performed on the premises. Vehicles not catered for by the Wythall workshops are covered by contractual service and inspection arrangements by agents with whom close liaison is maintained by a travelling service representative of the company.

Standardization of the tractive units of the car transporter artics into just heavy duty and normal duty categories is the target of the Group engineering director Mr D. S. Golding, familiarization on the part of the maintenance staff being regarded as a major advantage to be gained. Vehicles are replaced after five years or when they have covered 300,000 miles, if this mileage is completed in less than five years. Until recently, vehicles in the heavy-duty category were replaced at intervals of 500,000 miles. The yearly mileage of the fleet in 1970 was around 4m.

Priority factors

If a vehicle is withdrawn from service because of a breakdown, approximately £30 is debited against it for every day that it is off the road as the cost of non-utilization, which is additional to charges for maintenance and spares and any reduction of revenue arising from loss of goodwill. So reliability and freedom from accident are productivity factors that are given top priority by proper maintenance and by employing top-grade drivers. In common with the experience of other operators employing different makes of vehicle, the worst year for unpredictable and serious mechanical failures is the first year of the vehicle's life.

Detailed monthly inspections of all vehicles by skilled fitters, all of whom have had training as inspectors at Motec training establishments, normally enables a replacement or overhaul to be pre-planned some time ahead of necessity and, ideally, for the work to be included in a later scheduled service. Any defect is rectified immediately.

Conversely, if a vehicle is called in for an unscheduled repair, its scheduled service is brought forward, if it is practical to do so, and in the interests of vehicle utilization carried out at the same time as the unscheduled repair. It is considered that the inspection routine should be a specialist job and that the inspector should not be influenced by the need later to tackle the jobs listed on the inspection sheet.

At Wythall and other centres apart from Luton, AEC Mercury and Albion Chieftain CH51 tractive units will replace all other types in due course on a 50/50 basis for 26-ton-gross (heavy-duty) and 20-ton-gross (normal-duty) operations respectively, with the exception of two Leyland Lynx carriers that have been included in the fleet for evaluation purposes and one Albion Clydesdale.

While the load on the vehicles is normally considerably less than the rated payload, the contours of a laden or unladen vehicle and the gaps between the cars result in increased air drag at higher speeds, and the tractive units are far from being overpowered. Mr Golding favours ample power because it enables a useful cruising speed to be maintained on part throttle, which improves fuel economy and reduces the failure rate.

The engine of the AEC has an output of 151 bhp at 2400 rpm and fuel consumption averages about 8.92 mpg or 9.96 mpg according to the final drive ratio, which is either 6.92 to 1 to 6.27 to 1, the lower consumption being obtained when the higher ratio is employed. The Albion unit develops 138 bhp at 2600 rpm and averages 9.04 mpg running with a lighter load. The higher ratio has been proved to be operationally successful and it is now the policy of the company to standardize on this ratio for all new vehicles and to fit a drive with this ratio when "diff" replacements become necessary.

The heavy-duty outfits have an unladen weight of 11 tons and the maximum load is normally 111 tons (this is the weight of seven Land-Rovers) whereas the unladen weight of a normal-duty outfit is approximately 9+ tons and its payload is generally around 6+ tons. Typically, the load comprises five BLMC Minis on the top deck and four Minis or three bigger cars on the bottom deck. Apart from a few older vehicles, the use of which is, in the main, restricted to peak traffic periods, all the artics are 15-metre outfits.

Gearboxes

A Leyland GB 272 nine-speed splitter /overdrive gearbox is fitted to the Albions, while the AEC is equipped with a five-speed-and-overdrive box. Failure of the splitter box after 20,000/30.000 Miles was common in the early days, but driver instruction in its use gives promise that the failure rate may be lower in future. The favourable fuel consumption of the AEC may be partly explained by replacement of the 6.92 to 1 final drive with a drive having a ratio of 6.27 to 1.

Engaged in deliveries of Vauxhall cars, the Bedford KFA 16-ton and KGA 18-ton tractive units at the Luton, Ellesmere Port, Belfast and Folkestone centres are being phased out in favour of KHA 20-ton and KMB 24 ton tractive units. However, over recent months the KMB has proved most suitable and all new vehicles will be KMBs. No lighter vehicle will be included in the Dependable Delivery fleet.

The first cost of a prime mover and semi-trailer is well over £6000 and the semi-trailer maintenance costs are very high, which is in part attributable to the frequency of fatigue failure of the Main frame members. A number of Carter transporters is included in the fleet having lighter-than-normal frame members which reduce the taxation weight of the vehicle and are more flexible than the conventional type. The maker claims that this reduces fatigue stresses, and experience appears to justify the claim.

A very recent addition to the fleet, a Hoynor transporter (made by Redment Engineering Ltd), is equipped with hands Newway air suspension which gives a valuable saving in deck height of 6in. and will, it is hoped, eliminate fatigue fractures. It also appears to •enhance roll stability on bends .(notably on S-bends) by virtue of a roll-limiting feature that prevents excessive roll without impairing the suspension characteristics of the system.

Carter models include the 210, 310,.410 and 510. Carrimore transporters comprise Mk IV, VII and IX light-duty models and Mk IX heavy-duty types together with a number of modified MK us. Originally designed as five-car carriers, some of the Mk II and Mk III trailers have been extended by 8ft to carry seven light cars in such a way as to prevent overloading of the single 6-ton axle.

The Group's policy is to change tyres when the tread has worn to a depth of 2mm. Radial tyres are rebuilt once by the manufacturer, and conventional tyres are returned for casing credit. Road conditions at certain periods of the year present adhesion problems, particularly on driving axles; therefore in the interests of safety the tyres of driving axles are replaced when the treads have worn to a minimum of 4mm. On certain tyres at this stage in their life the lost mileage per millimetre could be as high as 10,000 miles but the improvement in traction on slippery roads and the gain in stability has fully justified this replacement policy. Safety considerations are given top priority. Because of early replacement, the percentage of covers accepted by manufacturers for rebuild is high.

The radials have an average life, according to application, of between 45,000 and 50,000 miles. Radials fitted on to the front tractive unit wheels are said to exaggerate steering vices such as shimmy or wander possibly because of the light axle loading, and it has proved beneficial to fit cross-ply tyres to some of the vehicles. Despite close attention to steering geometry and so on, cross-ply tyres do not average much more than 30,000 miles. High operating speed is, said to be a contributory factor in the relatively low mileage obtained.

While load-sensing valves are a favoured feature of braking systems as an aid to stability, experience has shown that mismatching can be dangerous. In a particular example no allowance was made for the increased stiffness of the rear springs provided by helper springs with the result that the front brakes of the tractive unit were doing more than their fair share of work. And this resulted in serious overheating of the brakes.

The cause of overheating was traced to mismatching of the load-sensing valve with the aid of a Triangle roller type brake tester that is equipped with a load simulator. Produced by the Raworth Engineering Company, the simulator is an hydraulic ram-and-chain device which can increase the load on the axle up to 8 tons, the ram being manually operated. Because the cost of galvanizing the structural members of the carriers would be prohibitive, it has been impossible to maintain the Vehicles in a clean-looking rust-free condition, despite regular repainting, partly because the members are subject to constant abrasion by the multiple securing chains. Shortly to be installed in the paintshop, shot-blasting equipment should enable this problem to be overcome.

The workshops cover an area of approximately 22,000 sq ft and a low-level area provides for four 50ft intercommunicating inspection pits equipped with the most modern type of water and lubricating-oil services. In addition to the brake tester mentioned earlier, the equipment of a drive-through inspection /test lane includes axle weighing with Checkweights. In due course, a dynamometer will be installed mainly with the object of facilitating smoke control. The lane leads to a 60ft inspection pit having a built-in travelling-jack system.

A drive-through vehicle washing area incorporates a full-length drained pit designed for under-chassis cleaning, while the paint shop is equipped with a ventilating system that gives a complete air change every two minutes. Other workshop features include a unit reconditioning shop, a fully stocked stores and a repair area for staff cars and personnel coaches.

Each of six thermostatically controlled oil-fired space heaters has a capacity of 600,000 Btu /h. Benches are of the portable type and portable oil and grease dispensing trolleys are available. Cleaning is facilitated by the use of a motorized self-propelled sweeper /collector.

Vehicles are inspected monthly (mileages vary up to 4500) and spot safety checks are carried out on a percentage of the fleet between the scheduled inspections. As mentioned earlier schedules are based on the reports of the monthly inspections, servicing and inspection being normally performed by personnel on night shift starting about 8 pm.

All transporter drivers are issued with a 10-page guide that gives detailed instructions regarding the handling and operation of the vehicle and observations that should regularly be made of equipment, the condition of which may affect the safety or serviceability of the vehicle. In general, the drivers have responded well to the guidance given and their reports of defects or suspected defects on an appropriate form have been a valuable aid to the inspection staff.

The policy of giving Kenning Tyre Services sole responsbility for tyre maintenance throughout the group has paid off in terms of tyre economy as well as reliability in service.

As a footnote on the operation of the transporters and driver training it is pertinent to mention particular hazards of handling the vehicles. Despite reducing deck heights to a minimum, the height of the loads is typically very nearly the maximum allowable when passing under the bridges of motorways which have a nominal minimum height of 16ft 6in but which in practice sometimes have a reduced height as the result of resurfacing. And overhanging trees that provide ample clearance in the normal way can be weighed down by snow, additional growth or a broken branch. Repairing the damage caused by trees can be very costly, and the hazard can easily escape the notice of the driver.

The most dangerous hazard of all operations is that which can be created by the overhanging front section of the top deck when the vehicle is negotiating a tight corner and lamp posts or buildings lie in the sweep of the deck. All the cabs of the tractive units are fitted with a window in the roof to enable the driver to take the necessary avoiding action in critical circumstances.