Operating Costs of Motorbus, Trolleybus
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and Tramcar
By H. Scott Hall,
Some Considerations on the Costs of Operation of Different Types of Passenger Vehicle to Supplement the Facts Embodied in an Article
in a Recent issue
THE figures given in the previous article under this heading and appearing in the Special Passenger Vehicle Issue are not unchallengable. It is equally true that I can with complete satisfaction reply to any challenge. The costs of operation of fleets of. public-service vehicles vary so widely that it is quite safe to blaze away into the brown : a hit is certain, mg Cost Variations.
As examples of this variation take these figures. The cost per mile of the overhead equipment for tramways in half a dozen examples, selected at random, varies from £1,160 to £3,000. The cost of maintenance of the same from £94 to £175 per mile per annum, whilst the maintenance of tramway tracks shows a variation in this same halfdozen examples of from £264 per mile per annum to £1,245!
A similar diversity can be recorded in reference to the overhead equipment for trolleybuses, which in one case is £2,600 per mile and in another 25,200—just double. The cost of maintenance varies from £50 per mile per annum to £145.
Result of Variance.
This element of elasticity gives me freedom to make the following approximations in estimating the operating cost of vehicles having a • seating capacity other than that exemplified in the previous article.
Consideration along these lines is necessary in order fairly to meet the claim that the tram is a more capacious vehicle and better adapted to deal with peak loads. Incidentally that claim is losing its force daily as the seating capacity of trolleybuses and buses increases, whilst that of trams is actually decreasing.In what follows I have n28
taken examples of medium capacity in all three classes of vehicle, avoiding extremes. in the case of buses I have assumed 55-seaters with freedom to carry five standing passengers, a total of 60; for the trolleybuses 65-seaters, plus five standing, and for trams 75-seaters, plus 10 standing.
The alterations as compared with the previous calculations affect the running cost of the trolleybusand tram. The former becomes 6.77d. per mile as against 6.15d., and the latter 5.83d. as against 4.98d.
If credit be given to the tram for its greater carrying capacity, then acknowledgment must also be made of the better average speeds of the bus and the trolleybus. In town traffic involving frequent stops the trolleybus is speediest. Fair averages for the three are 9, Si and 8 m.p.h. for trolleybus, bus and train respectively. This is a most important factor. It affects the cakula tions in two ways. It means that the annual mileage of the three cannot be the same and it is a telling factor in determining the total number of vehicles needed to move. a given number of persons per hour_
The differentiation in annual mileages affects the total cost of operation, inasmuch as the lower the figure for annual mileage the greater the incidence of standing charges. If I -Stick to the former figure of 30,000 miles per annum for the bus, then I must allocate 31,800 to the trolleybus and 28,200 •to the tram.
I will consider the effect on the standing charges. In the case of the tram the total cost per, mile becomes 11.78d. instead of 10.58d. and in the case of the trolleybus 12.77d. per mile as against 12.52d.
The incidence of the capital and maintenance costs of the track and overhead equipment also are
affected. The formula of the tram now becomes 2040 x M k 240 and
N x 28200 for he trolleybus 369 x M x 240 N x 31800 M and N as before representing the route mileage and the number of vehicles in service.
The alterations involved are not, as a matter of fact, sufficient to affect the total operating costs greatly.
The choice from the three types of vehicle is governed by expediency as well as by cost. In the case of a congested area the need to be able to deal with maximum traffic in minimum time is the interpretation of expediency in this connection.
Given Route Mileage.
It is that aspect which I now propose to examine, I shall assume a route mileage of four. Only rarely and in the largest cities is it worth while to consider the tram for journeys exceeding that length. I shall assume the necessity to convey an average of 2,500 people in an hour over the route.
The tram travelling at 8 m.p.h. takes half an hour for the journey, so that the first tram will only just roach the starting point again at -the expiration of the hour. Thirty trams will be necessary and a headway of two minutes. On that basis the incidence of the cost of the track and overhead equipment is equivalent to 2.32d. per mile and the total cost of operation per mile is 14.10d.
The trolleybus at 9 m.p.h. takes just over 27 minutes from point to point. The round journey, including a minimum overlay, will occupy 56 minutes and two trolleybuses will be available for a second journey within the hour. Thirty-five vehicles per hour will be necessary to carry the load so that 33 are necessary to operate the service. The incidence of cost of overhead equipment is 0.34d. per mile and the total cost per mile 13.11d.
More Motorbuses Needed.
A bus travelling at 8; m.p.h. completes the one-way journey in just over 28 minutes and as each bus carries 60 passengers 42 buses will be necessary. The cost of operation remains as before. namely, 14.25d. per mile for the petrol bus and 13.37d, for the oil-engined vehicle.
As in the previous case, these comparative costs are affected by the length of the route, and the accompanying diagram illustrates the variation in cost as the route mileage extends, assuming that the fore
going conditions remain unaltered.
The trolleybus, and in particular the tram, are handicapped in comparison with the bus. Neither can be operated until Parliamentary powers have been acquired. That involves legal expense, and, as is sometimes of greater consequence, delays in commencing to operate. Rates and taxes are payable upon the equipment and track.
The tramway operating concern is responsible for the upkeep of the roadway between the tracks and a strip along the outside thereof, also for restoring the roadway to its original condition when ceasing to operate the service.
None of these factors, however, can be represented as being an item of operating cost. Each undoubtedly has its bearing on the selection of the type of transport and must be considered accordingly. In certain cases it may be preferable to pay for upkeep of the road and the rates and taxes rather than bear the heavy cost of the road taxes on the vehicles, which, incidentally, axe already included in the above calculation of cost.
Only a knowledge of the precise conditions of each individual case will enable a decision to be reached on these points. None of them affects the application of the principles laid down in this and the previous article.