Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the length when the expected start of revenue is more than 2017?

### Inputs:
table_name: table, columns: ['Line', 'Speed', 'Length', 'Construction begun', 'Expected start of revenue services']

### Response:
SELECT Length FROM table WHERE Expected start of revenue services > 2017