About 95 percent of the males between twenty-five and sixty-four years of age are economically active. The percentage of economically active females is lower, but they have constituted over 40 percent of the labor force. About 36.5 percent of the economically active are employed in agricultural fields; of the remaining 63.5 percent, about one-half are employed in industry. The others are in various service, administrative, or other miscellaneous activities.
Because the country was late in emerging from a predominantly agricultural economy, its working force has had little technological experience. Since World War II, however, schools have been increasingly oriented to train young people to become technologically competent, and some success in this direction has been achieved. Whether or not the working force is being used as effectively as is possible under the circumstances is being debated, but the government finds a decrease in the birthrate and its possible limiting effect on industrial production a cause for considerable concern.
Railroads
The first railroad built in the country was constructed by the British in 1866 and connected Ruse on the Danube River with Varna on the Black Sea. The famous and romantic Orient Express and the Berlin-to-Baghdad route have used a common line through Bulgaria, entering the country from Belgrade. The route crosses the western mountains at the Dragoman Pass, continues through Sofia, Plovdiv, and down the Maritsa River valley to Edirne and Istanbul in Turkey.
The rail network consists of about 3,775 miles of track, about 2,620 of which were being operated in 1970. Of the portion in use, about 2,470 miles were standard gauge, and 150 were narrow gauge. Approximately 135 miles were double track, and a little more than 500 had been electrified. Because of the terrain, the system has a large number of bridges and tunnels and has been constructed with tighter curves and steeper gradients than are allowed when terrain features are less extreme. Most of the some 1,600 bridges are short, but at Ruse, where the Danube is crossed, the river is 1-½ miles wide. Most of the approximately 175 tunnels are also short. One is 3-½ miles in length, but they total only about thirty miles (see fig. 4).
Route mileage is adequate to meet the requirements of the country. It will probably not be expanded further; shorter spurs become uneconomic and are abandoned as motor transport takes over short-haul traffic. Programmed modernization includes improving roadbeds, ties, and track to achieve a higher load-bearing capacity. Quantity installation of continuously welded rail is also underway, and the busiest of the lines are being electrified.
Although the system is adequate, performs its services reasonably well, and continues to be the backbone of domestic transport, it suffers in bare statistical comparisons with the other carriers. Highway transport may carry a cargo to the rail station and get credit for a second shipment when it moves the same goods from the train to its final destination. Trucks also carry local freight more directly and much more simply than railroads for short hauls. Ton mileage statistics of the merchant marine are similarly misleading. Although the railroads remain by far the most important domestic carrier, their share of total cargo carried and their share of ton mileage continues to decrease (see table 2).
The railroads also continue to give way to motor vehicles in numbers of passengers carried. Between 1960 and 1970 the situation changed radically; on the earlier date the railroads carried more passengers than buses did, but a decade later they carried hardly more than one-third as many. In long-distance passenger travel, the railroads remained the major carrier by a narrow margin in 1970, although the difference was narrowing.