It was followed by 11 further pilot locomotives , which were extensively tested before the main order was built .
On 21 November 1972 the first locomotive , 151001 , was delivered by AEG and Krupp .
locomotive was followed by 11 further pilot locomotives , which were extensively tested before the main order was built .
On 21 November 1972 the first locomotive , 151001 , was delivered by AEG and Krupp .