user: Question: Name the build date for total produced of 146
Columns: ['Model', 'Specification', 'Build date', 'Total produced', 'Wheel arrangement', 'Prime mover', 'Power output']
Types: ['text', 'text', 'text', 'real', 'text', 'text', 'text']
Sample row: ['S-2', 'E1540', '1940–1950', 40.0, 'B-B', '6-539T', 'hp (kW)']
SQL:

assistant: SELECT "Build date" FROM "Table" WHERE "Total produced" = 146.0;