had reached $80 million—$18 million above the estimate for the whole 450-car fleet. The first car was delivered in August 1970, and within months, 10 test cars operated on the Fremont Line. The paid service began operation on 11 September 1972 on the 28 miles (45 kilometers) between Fremont and MacArthur Stations. Heavily subsidized by federal grants, 200 more cars were bought by July 1975. In the late 1980s, BART purchased another 150 from SOFERVAL, an American subsidiary of Alsthom Atlantique of France, and 80 more from Morrison-Knudsen a few years later.

A central control room, installed in 1972 in the Lake Merritt Administration Building, was replaced in 1979 by an Operations Control Center, from which train operations and remote control of electrification, ventilation, and emergency-response systems are supervised.

In 1991, the BART Extensions Program launched a $2.6 billion plan to expand services in Alameda, Contra Costa, and San Mateo Counties. Since then 5 stations and 21 miles (33 kilometers) of double track have been added, including the Pittsburg-Antioch Extension, whose North Concord/Martinez Station opened in December 1995, the first new one in over 20 years. The $517 million Dublin/Pleasanton Extension opened in May 1997. A proposal to connect BART to San Francisco International Airport (SFO) was first considered in 1972, just as the inaugural service was opened. The first stage opened in February 1996. During the next phase, BART will move further down the San Francisco peninsula, adding 9 miles (14.4 kilometers) of track and 4 new stations, including one inside the new International Terminal. Work on the final leg started in 1997, and the line was scheduled for completion early in the twenty-first century. In 1995, BART launched a ten-year program, costing $1.1 billion, to overhaul the system infrastructure and the original fleet of cars.

Further reading

Anderson, Robert M., et al. 1980. Divided Loyalties: Whistle-Blowing at BART. West Lafayette, IN: Purdue University Press.

Grant, Howard. 1976. Notes from Underground: An Architect’s View of BART. San Francisco: Reid and Tarics Associates.

Grefe, Richard, and Richard Smart. 1976. A History of the Key Decisions in the Development of Bay Area Rapid Transit. San Francisco: McDonald and Smart.

Baths of Caracalla

Rome, Italy

The Baths of Caracalla (Thermae Antoninianae) were built between a.d. 212 and 216 by the emperor Marcus Aurelius Antoninus (a.d. 188–217), usually known as Caracalla. Although in layout the Baths of Caracalla largely emulated the model established about a century before in the Baths of Trajan, their massive scale and opulent internal finishes were without precedent. Their fully integrated plan and imposing scale and grandeur amply demonstrated the Romans’ design skills. Significantly, the baths demonstrated the structural advances made possible through the masterful use of concrete to span vast spaces using barrel and groin vaults, domes, and half-domes, as well as the sophisticated mechanical engineering services developed by the Romans.

Public baths (thermae) were an essential part of all Roman towns. The majority of citizens lived in crowded tenements (insulae) without running water or sanitary facilities, so communal baths were constructed and made available to both sexes of all social classes. Entry was free. Generally, mixed bathing was not favored, so the baths were open to women in the mornings and men in the afternoons and evenings. The thermae were the center of Roman social life—people could meet friends there and engage in any number of leisure and cultural pursuits on offer. As well as changing rooms, gymnasia, saunas, and pools of various temperatures, there were libraries, museums, restaurants, bars, shops, lecture theaters, concert halls, playing fields, gardens, and courtyards, all richly furnished with mosaics, fountains, and statues. Although extremely costly to build, the baths were a political investment—a means for the emperor to demonstrate his concern for the well-being of the community.

The Baths of Caracalla occupied a 50-acre (20.25-hectare) site. The complex was divided into three parts: the rectangular main building, approximately 750 by 380 feet (225 by 115 meters) and large