line (sections Épernay - Châlons-sur-Marne, Vitry-le-François - Bar-le-Duc and Lunéville - Sarrebourg). While the locomotive had no technical difficulties at those speeds, the project was not continued due to the enormous cost of the infrastructure works which had to be undertaken. In 1973, BB15008 was used to test communication interferences on the now defunct Überherrn-Wadgassen line in Germany, exceptionally fed with 25 kV at that time. In 1974, BB15007 was taken out of service and transformed into BB7003, the prototype for the BB7200 locomotives. See SNCF Class BB 7003. In 1976, BB15015 was tested on the Marseille-Nice main line in order to prepare the line for the arrival of the similar, but bicurrent BB22200 locomotives. In 1977, BB15041 operated special demonstration rides between Épernay and Châlons-sur-Marne at for Amtrak executives in order to convince them to buy a locomotive based on this design rather than the Swedish-based AEM-7. Eventually six-axle locomotive CC21003 was rebuilt to US standards and sent to the United States instead. In 1978, BB15012 received the lower-geared bogies of locomotive BB22201 and was tested on various lines with heavy freight trains with weights up to , in order to test the performances against BB22000 locomotives. In 1979, BB15063 was equipped with the bogies of BB7248 which had a modified secondary suspension for operating in the Middle East. The Iranian Railways were interested in purchasing a locomotive class based on the BB15000 design. BB15063 was tested with heavy trains up to on various 25 kV lines. BB15063 retains these special bogies even today. In 1979 BB15030 was used for stability tests in the Marne valley region at speeds up to . In 1980, a BB15000 locomotive pulled middle cars of a TGV Sud-Est train set at high speeds in preparation of their services on the LGV Sud-Est. Later that year, BB15008 was sent to the Rail Tec Arsenal climatic test chamber in Vienna for thermal tests up to . In 1981, locomotives BB15049 and BB15059 were used for testing the behaviour of the AM18U pantographs at high speeds in tunnels, related to use in the then not yet built Channel Tunnel. In 1982, BB15055 received synchronous motors. Later that year it was renumbered BB10004. See SNCF Class BB 10004. Also in 1982, BB15056 received a bimotor bogie with motors similar to the ones used in TGV Sud-Est sets. In 1983, BB7003 (original BB15007) was transformed into BB10003, a