Some Erroneou deas Concerning Ton-mileage
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Criticism of Certain Published Information About Ton-mileage Leads to Enunciation of Some Principles Which Ancillary Operators and Some Hauliers Should Adopt WHEN going through my. files recently, in order to
• give some useful aid to inquirers about ton-mileage.
I came across a cutting of an article, published some years ago, which was meant, primarily', to interest commercial-vehicle operators in the use of graphs as a means for enabling them to effect economies, and it included a reference to ton-mileage and cost per ton-mile. It was ...suggested that the ton-mile figure was the most suitable one for the operator to use in his research into cost of transport. Indeed, the graph which accompanied the article was one showing variations in cost per ton-mile.
I cannot trace from which journal the cutting was taken except, to assure myself, that it was not one of those devoted directly to the interests of commercial-motor users.
I cannot, therefore, give due acknowledgement and, if the editor Of the journal happens to see this article. I must ask him to accept my apologies on that account. I should like the author too, to appreciate that the criticisms which I am about to make are made in good faith.
Table I and the graph are taken from the article. Neither wa,s complete, and I had to fill in the last two columns of the table relating to sections D, E and 17, as well as complate the graph for sections C. D and F. ,
I would like to make it clear that I have not altered the graph in any essential particular, and I am not responsible for it. I do not understand why there is no graph of section A.
How Ton-mile System Was Worked The article, in suggesting the use of graphs for the purpose al eady mentioned, stated that the dispatch manager is responsible for costs and should, therefore, be directly interested in the problem of cost per ton-mile. It was further stated that the graphical method, shown in the article, had been successfully applied to a large organization. situated. in Central London, which was concerned with the dispatch of textile and rubber products to all parts of the country. Of the iota' of goodc sent out 90 per cent, went by road.
The country it divided into six main sections as follow Section A.-Radius of 40 miles from London.
Section B.-Radius of 60 mile_ from Birmingham, Section C -Radius of 100 miles from Leeds.
Section D.-Radius of 100 miles from Ipswich.
Section E.-Radius 01 100 miles from Southampton Section F -Radius of 100 miles from Cardiff.
Table I was put forward as showing an analysis of cost per ton-mile of goods carried to each of these sections. From this table, it was said, 'could be ascertained, not only the cost per ton for any section, but the cost per ton mile. Both these figures, it was asserted, would prove useful in discussing rates and bargaining with hauliers.
I should be interested to know how bargaining with hauliers could be facilitated by the use of a figure for ton-mileage because it is my experience that not one haulier ,in a thousand really knows what a ton-mile is, let alone what its cost is or should be,
I am writing this criticism, first with the object of disabusing anyone who may think of the ton-mile in the same way as the writer of the article, and, secondly, because the moral to be drawn, as I shall show, is that there are two principal items of cost which are helpful to the operator. in achieving, the object which the writer of this article has in view, namely, the effecting of economies in the transport of his goods
There is notbing in the article to indicate how the figure
given for ton-mileage has been ca culated, and I have li.ad to discover that for myself. Fortunately, the problem is easy of solution. It can be solved by consideration of the first line of Table I relating to operations in section A. The figure for total cost is given at £15 2s. 2d. and the cost per ton-mile as 0.344d. Obviously, therefore, if £15 2s. 2d. be divided by 0.344d. we shall obtain the figure for the number of ton-miles completed by the vehicle operating section A. The result of that simple arithmetical calculation is 10,540 and that is as near as makes no matter the same as is obtained by multiplying 16.48, the tonnage carried, by 640, the total mileage.
Now, as I have explained in previous articles, the tonmileage figure is obtained by multiplying the actual tons carried by the miles covered while the load is being carried, and if this figure for ton-mileage means anything at all it is that the vehicle operating in section A has, during the whole distance of 640 miles covered daring the month, been continuously carrying 16.48 tons, which is absurd.
Actual Versus Hypothetical Figures As the vehicle has covered 640 miles within a radius of 40 miles it may be assumed, taking the simplest possible case first, that it has completed eight journeys of 40 miles out and 40 miles home in that period. On each journey it carried a load of 2.06 tons, taking it for 40 miles, delivering it and returning empty. The average length of haul is, therefore, to be taken as 40 miles and the tonmileage as 40, multiplied by 2.06, which is 82.4. The total mileage for the month, that is for the eight journeys, is eight times that figure, which is 659.2 ton-miles as compared with the author's figures of 10,540, As the total cost is £15 2s. 2d., the cost per ton-mile is 5.5d., which is vastly different from the 0.344d. quoted in Table I. 'Table II has been compiled on assumed conditions such as are more likely to occur in practice, that is to say the vehicle takes a different route each time so , that the journeys are not all of the same length, and that • it carries a different load on each occasion.
It will be noted that there are 12 journeys the lead mileage per journey varying from a minimum of nine to a maximum of 44, and the distance covered varying from a: minimum of 20 miles to a maximum of 90 miler. The total mileage covered during the month is. still 640, as set down in Table I. The tonnage carried on each journey varies from a minimum of 0.5 on journey No, 9, to a maximum of 2.1 on journey No. 7, but the total tonnage for the month still remains at 16,48.
In Column 5 I have set-out the ton-mileage -for each journey, properly calculated in accordance with accepted principles-that is multiplying the distance in miles by the tonnage carried. The ton-mileage for the month now seems to be no more than 467.92, as compared with 659.2 by the simple method, and 10,540 by the erroneous one used by the writer of the article.
Before I could carry the comparison any farther I had to calculate the cost per mile of running this vehicle.i Dividing the total cost, 15 2s. 2d., by the mileage, I find that the vehicle-cost per mile is 5.6d. Obviously, there is something wrong there for, in order to carry the load stipulated, the vehicle must be a 2-touner, and. I know of no 2-tonner that can be operated at 5.6d. per mile if it be covering no more than 640 miles per month.
IIowever, that is the figure of cost which must be used in these calculations, so that I can tine up all my own conclusions for comparison with those in the original Table I. Using, therefor, the figure of 5.6d. per mile I am able to calculate, as set. down in Column 6, the cost of each journey. The total, it should be noted, is still the same as in Table I, namely, £15 2s. 2d.
In Column 7 is the cost per ton, arrived at by dividing the cost for the journey set out. in Column 6 by the actual weight carried in tons. In Column 8 is the real cost per ton-mile, which is found by dividing the actual ton-miles into the cost of the journey. It should be noted that the essential and factual figures in Table I, the tons carried (16.48), the mileage run (640) and the cost (£15 2s. 2d.), have not been altered. ,
My first point in this, as in previous articles, is to demonstrate the labour involved in arriving at.figures for ton-mileage and cost per ton-mile. Each journey has to he assessed independently, as I have done. In actual fact, it is quite likely that the work would be much more involved even than is shown here, for, as this is a case of distribution from a factory to consignees within a, specified zone, it is more than likely that each journey would involve a number of calls, dropping a small portion of the load at each, so that the calculation of the ton-mileage would have to be along the lines described in my previous article as set out in Tables II and III of that article.
It' is possible to show, moreover, that the figures for ton-mileage, even assuming journeys so simple and easy of assessment as those in Table II, may differ widely. while the conditions of operation remain ahnost the same.
It is not to be expected, for example, that the loads and distances will be identical, month after month, as those set out in Table II. If they do vary the ton-mileage will vary. As an example of what may happen I have compiled a similar set of figures in Table III, assuming that the journeys are the aame but that the loads vary. This is something which might reasonably be expected, as the vehicle will probably convey goods to the same series of consignees, month after mouth.
Compare Table III with Table II and it will be noted that, whilst I have still kept to the total tonnage, total mileage and total cost as before, the ton-mileage and the cost per mile are quite different.
I am quite certain that no dispatch manager would be able, by reference to any figures for cost per ton-mile, whether they be real figures such as I have set out in Tables II and HI, or the meaningless figures as set out in Table I, to check up his costs in any practical way with a view to effecting economies unless he had before him much more information than is embodied in Tables II and III. Furthermore, the graph 'which, it is suggested, will he such an aid to that objective is, in my view, completely useless. There are two items of information which are essential to the operator who is trying to devise means for economizing in his transport costs. They are, first, the actual and real operating cost per mile of each vehicle, arrived at by the methods I have so-often recommended in these 'articles, and secondly, the cost per ton, package,
barrel, or sack, as the case may he. .
He must use these two items in this way. Keep a careful check on vehicle cost, especially the items of fuel, maintenance, tires and overheads, in order to ensure that those costs shall be at a minimum and in order to contrive that such economies as are possible are effected.
Given that the cost of running the vehicle is at a minimum, the cost per ton, etc., depends upon the routing of his traffic, the cutting out of unnecessary and redundant mileage, and arranging that the maximum tonnage be Carried on each journey. What I mean by this latter statement may be, to some extent, covered by reference to Tables II and III. In journey No. 7, for example, the longest of the 12, the load carried, according to Table If, is 2.1 tons, and the cost per ton is £1 Os. 3d. For the same journey, according to Table III, only ton is carried, with the result that the cost per ton is, £4 5s.
As a pointer, showing that ton-mile figures are of no value, it is interesting to compare costs per ton-mile, from items given in either Table II or Table III, with the cost per ton to show that there is no relation between them, For example, in journey No. 7-Table II-the cost per ton is* £1 Os. 3d., and the cost per ton-mile 5.5d., whereas, ' on journey No. 9, whilst the' cost per ton has risen only to el. 2s. 8d., the cost per ton-mile is 27.2d.
The operator knows that his vehicle cost, of 5.6d. per mile run, has been brought to the irreducible mininnim, and he must, therefore, make it his business to discover whether it is not possible, on' journey No. 7,-more frequently to arrange that the vehicle carries 2.1 tons instead
of 0.5 ton. S.T.R.