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 | Wheel arrangement | Fleet number(s) | Manufacturer | Year made | Quantity made | Quantity preserved | Year(s) retired |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 2-8-2 — oOOOOo — Mikado | 2-8-2 — oOOOOo — Mikado | 2-8-2 — oOOOOo — Mikado | 2-8-2 — oOOOOo — Mikado | 2-8-2 — oOOOOo — Mikado | 2-8-2 — oOOOOo — Mikado | 2-8-2 — oOOOOo — Mikado | 2-8-2 — oOOOOo — Mikado |
| W | 2-8-2 | 1500–1659 | Alco ( Brooks ) | 1904–1907 | 160 | 0 | 1930–1959 |
| W-1 | 2-8-2 | 1660–1699 | Alco ( Schen. ) | 1910 | 40 | 0 | 1925–1958 |
| W-2 | 2-8-2 | 1900–1919 | Alco ( Brooks ) | 1904–1905 | 20 | 0 | 1930–1958 |
| W-3 | 2-8-2 | 1700–1834 | Alco ( Brooks ) | 1913–1920 | 135 | 1 | 1926–1960 |
| W-4 | 2-8-2 | 2500–2505 | NP ( Brainerd Shops ) | 1919 (rebuilt) | 6 | 0 | 1955–1958 |
| W-5 | 2-8-2 | 1835–1859 | Alco ( Schen. ) | 1923 | 25 | 0 | 1952–1960 |
Question:
Which class had a quantity made of 20?
Answer:
W-2