user: Question: What is the length when the expected start of revenue is more than 2017?
Columns: ['Line', 'Speed', 'Length', 'Construction begun', 'Expected start of revenue services']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['Svilengrad -Turkish Border', '200km/h', '19km', '2010', 2012.0]
SQL:

assistant: SELECT "Length" FROM "Table" WHERE "Expected start of revenue services" > 2017.0;