locomotives is a little lower for electrics. Lubrication costs is less for electrics (they have no diesel engines to fill with lubricating oil). Countering the cost advantages of electric traction are the cost disadvantages of electrification: primarily the costs of the catenary and substations (including maintenance costs). It turns out that roughly half of the yearly cost is for depreciation to pay back the original cost of the installation and the other half is for maintenance. An important factor was the use of the railway electric power system in the Soviet Union to supply public power to residences, farms, and non-rail industry which in the early 1970s consisted of about 65% of the electric energy used by trains. Thus the sharing of costs of electrification with external electricity consumers reduces the cost of rail electrification resulting in reduced yearly electrification costs of 15–30%. It's claimed that this cost sharing significantly unfairly favored the external users of electricity at the expense of the railway. However (in the early 1970s) it's claimed that the annual cost of rail electrification (including maintenance) was only a third to a half of the benefits of savings in fuel costs thus favoring electric traction (if the interest cost of capital is neglected and the traffic is fairly high). Historical costs of locomotive operation: Electric vs. Diesel The following table shows these costs for both 1960 and 1974 in roubles per 100,000 tonne-km gross haulage of freight. These costs include capital cost by the use of depreciation charges (in a non-inflation environment). Note that "depreciation" for electric traction includes maintenance and depreciation charges for the catenary and electric substations. For both types of traction, depreciation of the repair shops are included. For diesel traction there is depreciation of fueling facilities. The higher depreciation of the diesel locomotive is more than made up for by the depreciation of the catenary and substations for the case of electric traction. In 1960 electric and diesel were about equal in cost but in 1974, after a significant increase in the price of diesel fuel due to the 1973 oil crisis, electric traction became lower in cost. Note that there are no interest charges added to depreciation. Total yearly cost comparison Per the calculations by Dmytriev Even a low traffic-density line with 5 million tonne-km/km (in both directions) will pay back the cost of electrification if the interest rate is zero (Ен=0)