The Bay Area Rapid Transit system- a commuter network of highspeed rail lines- opened in the San Francisco area early in 1971. Some of the most formidable challenges have resulted from the fact that part of the BART system had to be constructed to a spiraled alignment through solid rock. Additionally, this tunneling required a 12 inch thick steel reinforced concrete liner to protect the tube against possible shifts in the rock formation. Because of all the directional changes, it appeared that a form might have to be built for each section instead of using continuous forming. The problem was solved, however, with an adjustable invert form that could be angled to accommodate the banking of curves and changes in elevation. The special forms had the usual traveler through the tunnel, except that one side was raised in the curved portions to provide banking. This resulted in a traveler with tracks of varying width. A drag screed was designed and built on which all the necessary adjustments could be made. The screed could be raised from 0 to 7 and one-half inches on the right side, and distance between the tracks varied up to 7 inches. The same adjustable screed was used to provide the re-elevation for both inbound and outbound portions of the tunnel, with variations in calculations.