Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Class | Wheels | Date | No. built | Loco Nos. |
| --- | --- | --- | --- | --- |
| H1 | 4-4-2 | 1905-6 | 5.0 | 37-41 |
| C3 | 0-6-0 | 1906 | 10.0 | 300-309 |
| I1 | 4-4-2T | 1906-7 | 20.0 | 1-10,595-604 |
| I2 | 4-4-2T | 1907-8 | 10.0 | 11-20 |
| I3 | 4-4-2T | 1907-13 | 27.0 | 21-30,75-91 |
| I4 | 4-4-2T | 1908 | 5.0 | 31-35 |
| J1 | 4-6-2T | 1910 | 1.0 | 325 |
| H2 | 4-4-2 | 1911-2 | 6.0 | 421-6 |
Question:
On what date was the number of locomotives 421-6?
Answer:
1911-2