Transport aspects and quality of customer service, Selection...

Transport aspects and quality of customer service

Consumers determine the amount or lot of product delivery, the managers of the warehouse management determine the volume of goods turnover (the volume of deliveries of products) of the segment they serve, and the transport managers determine the rolling stock (car) and the optimal routes for the transportation of products.

Consider the methodology for selecting the rolling stock, as well as characterize the routes of traffic and their optimization.

Selection of rolling stock for the transport of products

Consider some examples of the choice of rolling stock.

Comparison of the advantage of using an on-board car or a tractor with a replacement trailer ( semitrailer )

The criterion of choice in this case can be an equivalent distance , which is set provided that the hourly performance of the car will be equal to the hourly performance tractor , i.e. :

where - the carrying capacity of the vehicle and trailer systems, respectively towed by a tractor, t; - the idle time of the car for loading and unloading, h; - time of trailer coupling, h; β is the mileage utilization factor; - technical speed of the car and tractor, respectively, km/h.

The resulting equivalent distance is compared with the distance of transportation.

1. If the distance of transportation is less than equivalent, i.е. , you should use a tractor, if , then you need to apply the car. This is due to the fact that short distances of transportation to the trailer coupling are less time consumed than for simple on-board vehicles for loading and unloading.

2. If, in determining the equivalent distance in the denominator, a negative value is obtained, select the tractor, because ; If the numerator is negative, you should choose a car.

Example 1

Determine the feasibility of using a tractor or a car, if the carrying capacity of each of them is 5 tons, the technical speed of the car is km/h, tractor km/h, mileage utilization rate , vehicle idle time for loading and unloading 0.8 hours, and re-take time 0.1 hours. Transport distance is km.

Solution. We use the formula for determining the equivalent distance and calculate its value by the formula

Since the distance is less than the equivalent (20 <35), a tractor should be used.

Example 2

Determine the profitability of using a 5-ton vehicle in comparison with a 4-ton tractive unit for working at a distance of 25 km, if the technical speed of the vehicle is km/h, vehicle idle time for loading and unloading 0.5 h, time for trailer coupling 0.1 h, mileage utilization factor β = 0.5.

Solution. Calculate the equivalent distance by the formula

Since the distance of transportation is more than equivalent (25 & gt; 4.3), you should use the car.

Comparison of the advantage of using an on-board vehicle or a dump truck

The criterion of choice in this case is also the equivalent distance , which is determined using the hourly performance of the onboard car and dumper. Graphical change in the hourly performance of an on-board vehicle and a dumper depending on the length of the loaded trip, as well as an equivalent distance, are shown in Fig. 6.19.

Equal Distance Chart

Fig. 6.19. Equal distance graph

Equivalent distance is determined by the formula

where - mileage utilization factor; - technical speed of the dumper and the vehicle, km/h; - carrying capacity of the vehicle, t; - gain in time for unloading the truck, h; - loss in load-carrying capacity of a dump truck in comparison with an onboard car, t; - loading and unloading time of the vehicle, h. If the distance of the carriage is less than the equivalent , i.e., a dump truck should be used, if, an on-board vehicle should be used (see Figure 6.19 ).

Example 3

Which car is more profitable to use (onboard or dumper), if the distance of the loaded trip is 20 km, the load capacity of the on-board vehicle t, dump truck t, time for loading and unloading of the onboard car h, dump truck h. The mileage utilization coefficient is β = 0.5, the technical speed is km/h.

The solution. We find the value of the decrease in the load capacity of a dump truck in comparison with an on-board car:

Determine the gain in the time of unloading the truck:

Equivalent distance will be equal to

Since a given distance of 20 km is greater than an equivalent distance (20 & gt; 12.5), in this case an on-board vehicle should be used.

Selecting the type of car at the cost of transporting goods The choice of type of car can be determined at a cost of 1 ton-kilometer (tkm). Determine the cost of 1 tkm of cars compared and give preference to the car, the cost of tonne-kilometer of which is less.

The cost of 1 tkm can be determined by the formula

where - the sum of variable costs for 1 km, rub .; - mileage of the car for one run, km; - the amount of fixed costs per vehicle, hrs; - the time of one ride, h; - transport work for one run, tkm; - the driver's salary plan for one ride, rubles.

Since , the formula takes the following form:

where γ is the load utilization factor.

Example 4

Determine the profitability of using a vehicle with a load capacity of 5.0 tons compared to a vehicle with a load capacity of 4.0 tons under the following conditions: distance of carriage km, mileage utilization rate, the utilization rate of the load capacity. The technical speed of a 5-ton vehicle is km/h, and a 4-ton vehicle is 20 km/h, idle time for loading and unloading for one vehicle for a 5-ton vehicle is 0.7 h, and 4-ton - 0.5 h.

The costs for each model are equal to

Cost Types

5 tons

4 tons

Spec "- variable costs, rubles/1 tkm

6.0

5.0

C-sum of fixed costs per vehicle, h, rub.

30.0

25.0

The driver's salary for one ride, rubles.

80.0

60.0

Decision. The cost of 1 tkm when carrying out transportation by a vehicle with a payload capacity of 4 t is calculated using the formula

Cost of 1 tkm when carrying out transportation by car with a load capacity of 5 tons:

The cost of 1 tkm of a car with a carrying capacity of 5 tons turned out to be lower than that of a 4T vehicle (4.86 & lt; 5.03), so we choose a vehicle with a carrying capacity of 5 tons for this transportation.

thematic pictures

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